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Aellos F, Grauer JA, Harder KG, Dworan JS, Fabbri G, Cuevas PL, Yuan X, Liu B, Brunski JB, Helms JA. Dynamic analyses of a soft tissue-implant interface: Biological responses to immediate versus delayed dental implants. J Clin Periodontol 2024. [PMID: 38708491 DOI: 10.1111/jcpe.13980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 02/16/2024] [Accepted: 03/10/2024] [Indexed: 05/07/2024]
Abstract
AIM To qualitatively and quantitatively evaluate the formation and maturation of peri-implant soft tissues around 'immediate' and 'delayed' implants. MATERIALS AND METHODS Miniaturized titanium implants were placed in either maxillary first molar (mxM1) fresh extraction sockets or healed mxM1 sites in mice. Peri-implant soft tissues were evaluated at multiple timepoints to assess the molecular mechanisms of attachment and the efficacy of the soft tissue as a barrier. A healthy junctional epithelium (JE) served as positive control. RESULTS No differences were observed in the rate of soft-tissue integration of immediate versus delayed implants; however, overall, mucosal integration took at least twice as long as osseointegration in this model. Qualitative assessment of Vimentin expression over the time course of soft-tissue integration indicated an initially disorganized peri-implant connective tissue envelope that gradually matured with time. Quantitative analyses showed significantly less total collagen in peri-implant connective tissues compared to connective tissue around teeth around implants. Quantitative analyses also showed a gradual increase in expression of hemidesmosomal attachment proteins in the peri-implant epithelium (PIE), which was accompanied by a significant inflammatory marker reduction. CONCLUSIONS Within the timeframe examined, quantitative analyses showed that connective tissue maturation never reached that observed around teeth. Hemidesmosomal attachment protein expression levels were also significantly reduced compared to those in an intact JE, although quantitative analyses indicated that macrophage density in the peri-implant environment was reduced over time, suggesting an improvement in PIE barrier functions. Perhaps most unexpectedly, maturation of the peri-implant soft tissues was a significantly slower process than osseointegration.
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Affiliation(s)
- Fabiana Aellos
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Joseph A Grauer
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
- Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kasidy G Harder
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
- Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Julia S Dworan
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
- Department of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Giacomo Fabbri
- Private Practice, Ban Mancini Fabbri Dental Clinic, Cattolica, Italy
| | - Pedro L Cuevas
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Xue Yuan
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Bo Liu
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - John B Brunski
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Jill A Helms
- Department of Surgery, Stanford University School of Medicine, Stanford, California, USA
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Coyac BR, Wolf BJ, Bahat DJ, Arioka M, Brunski JB, Helms JA. A WNT protein therapeutic accelerates consolidation of a bone graft substitute in a pre-clinical sinus augmentation model. J Clin Periodontol 2022; 49:782-798. [PMID: 35713219 DOI: 10.1111/jcpe.13674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 04/28/2022] [Accepted: 05/28/2022] [Indexed: 11/30/2022]
Abstract
AIM Autologous bone grafts consolidate faster than bone graft substitutes (BGSs) but resorb over time, which compromises implant support. We hypothesized that differences in consolidation rates affected the mechanical properties of grafts and implant stability, and tested whether a pro-osteogenic protein, liposomal WNT3A (L-WNT3A), could accelerate graft consolidation. MATERIALS AND METHODS A transgenic mouse model of sinus augmentation with immunohistochemistry, enzymatic assays, and histology were used to quantitatively evaluate the osteogenic properties of autografts and BGSs. Composite and finite element modelling compared changes in the mechanical properties of grafts during healing until consolidation, and secondary implant stability following remodelling activities. BGSs were combined with L-WNT3A and tested for its osteogenic potential. RESULTS Compared with autografts, BGSs were bioinert and lacked osteoprogenitor cells. While in autografted sinuses, new bone arose evenly from all living autograft particles, new bone around BGSs solely initiated at the sinus floor, from the internal maxillary periosteum. WNT treatment of BGSs resulted in significantly higher expression levels of pro-osteogenic proteins (Osterix, Collagen I, alkaline phosphatase) and lower levels of bone-resorbing activity (tartrate-resistant acid phosphatase activity); together, these features culminated in faster new bone formation, comparable to that of an autograft. CONCLUSIONS WNT-treated BGSs supported faster consolidation, and because BGSs typically resist resorption, their use may be superior to autografts for sinus augmentation.
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Affiliation(s)
- Benjamin R Coyac
- Division of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA.,Department of Periodontology and Implant Dentistry, School of Graduate Dentistry, Rambam Health Care Campus, Haifa, Israel
| | - Benjamin J Wolf
- Division of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - Daniel J Bahat
- Division of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - Masaki Arioka
- Division of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
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3
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Tian Y, Sadowsky SJ, Brunski JB, Yuan X, Helms JA. Effects of masticatory loading on bone remodeling around teeth vs. implants: insights from a preclinical model. Clin Oral Implants Res 2022; 33:342-352. [PMID: 35051302 DOI: 10.1111/clr.13894] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 12/10/2021] [Accepted: 12/19/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Teeth connect to bone via a periodontal ligament whereas implants connect to bone directly. Consequently, masticatory loads are distributed differently to periodontal versus peri-implant bone. Our objective was to determine how masticatory loading of an implant versus a tooth affected peri-implant versus periodontal bone remodeling. Our hypothesis was that strains produced by functional loading of an implant would be elevated compared to the strains around teeth, and that this would stimulate a greater degree of bone turnover around implants versus in periodontal bone. MATERIALS AND METHODS Sixty skeletally mature mice were divided into two groups. In the Implant group, maxillary first molars (mxM1) were extracted, and after socket healing, titanium alloy implants were positioned sub-occlusally. After osseointegration, implants were exposed, resin crowns were placed, and masticatory loading was initiated. In a Control group the dentition was left intact. Responses of peri-implant and periodontal bone were measured using micro-CT, histology, bone remodeling assays, and quantitative histomorphometry while bone strains were estimated using finite element (FE) analyses. CONCLUSIONS When a submerged osseointegrated implant is exposed to masticatory forces peri-implant strains are elevated, and peri-implant bone undergoes significant remodeling that culminates in new bone accrual. The accumulation of new bone functions to reduce both peri-implant strains and bone remodeling activities, equivalent to those observed around the intact dentition.
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Affiliation(s)
- Ye Tian
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, California, 94305, USA
| | - Steven J Sadowsky
- University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, CA, USA
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, California, 94305, USA
| | - Xue Yuan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, California, 94305, USA
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, California, 94305, USA
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Yuan X, Pei X, Chen J, Zhao Y, Brunski JB, Helms JA. Comparative analyses of the soft tissue interfaces around teeth and implants: Insights from a pre-clinical implant model. J Clin Periodontol 2021; 48:745-753. [PMID: 33713489 DOI: 10.1111/jcpe.13446] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/21/2021] [Accepted: 02/01/2021] [Indexed: 02/05/2023]
Abstract
AIM To evaluate the similarities and differences in barrier function of a peri-implant epithelium (PIE) versus a native junctional epithelium (JE). MATERIALS AND METHODS A mouse model was used wherein titanium implants were placed sub-occlusally in healed extraction sites. The PIE was examined at multiple timepoints after implant placement, to capture and understand the temporal nature of its assembly and homeostatic status. Mitotic activity, hemidesmosomal attachment apparatus, and inflammatory responses in the PIE were compared against a JE. Additionally, we evaluated whether the PIE developed a Wnt-responsive stem cell niche like a JE. RESULTS The PIE developed from oral epithelium (OE) that had, by the time of implant placement, lost all characteristics of a JE. Compared with a JE, an established PIE had more proliferating cells, exhibited lower expression of attachment proteins, and had significantly more inflammatory cells in the underlying connective tissue. Wnt-responsive cells in the OE contributed to an initial PIE, but Wnt-responsive cells and their descendants were lost as the PIE matured. CONCLUSIONS Although histologically similar, the PIE lacked a Wnt-responsive stem cell niche and exhibited characteristics of a chronically inflamed tissue. Both features contributed to suboptimal barrier functions of the PIE compared with a native JE.
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Affiliation(s)
- Xue Yuan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, CA, USA
| | - Xibo Pei
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jinlong Chen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuan Zhao
- Department of Cariology and Endodontology, School of Dentistry, Lanzhou University, Lanzhou, China
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, CA, USA
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, CA, USA
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de Barros e Lima Bueno R, Ponce KJ, Dias AP, Guadarrama Bello D, Brunski JB, Nanci A. Influence of Nanotopography on Early Bone Healing during Controlled Implant Loading. Nanomaterials (Basel) 2020; 10:nano10112191. [PMID: 33153132 PMCID: PMC7693286 DOI: 10.3390/nano10112191] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022]
Abstract
Nanoscale surface modifications influence peri-implant cell fate decisions and implant loading generates local tissue deformation, both of which will invariably impact bone healing. The objective of this study is to determine how loading affects healing around implants with nanotopography. Implants with a nanoporous surface were placed in over-sized osteotomies in rat tibiae and held stable by a system that permits controlled loading. Three regimens were applied: (a) no loading, (b) one daily loading session with a force of 1.5N, and (c) two such daily sessions. At 7 days post implantation, animals were sacrificed for histomorphometric and DNA microarray analyses. Implants subjected to no loading or only one daily loading session achieved high bone-implant contact (BIC), bone-implant distance (BID) and bone formation area near the implant (BFAt) values, while those subjected to two daily loading sessions showed less BFAt and BIC and more BID. Gene expression profiles differed between all groups mainly in unidentified genes, and no modulation of genes associated with inflammatory pathways was detected. These results indicate that implants with nanotopography can achieve a high level of bone formation even under micromotion and limit the inflammatory response to the implant surface.
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Affiliation(s)
- Renan de Barros e Lima Bueno
- Laboratory for the Study of Calcified Tissues and Biomaterials, Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC H3C3J7, Canada; (R.d.B.e.L.B.); (K.J.P.); (A.P.D.); (D.G.B.)
| | - Katia J. Ponce
- Laboratory for the Study of Calcified Tissues and Biomaterials, Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC H3C3J7, Canada; (R.d.B.e.L.B.); (K.J.P.); (A.P.D.); (D.G.B.)
| | - Ana Paula Dias
- Laboratory for the Study of Calcified Tissues and Biomaterials, Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC H3C3J7, Canada; (R.d.B.e.L.B.); (K.J.P.); (A.P.D.); (D.G.B.)
| | - Dainelys Guadarrama Bello
- Laboratory for the Study of Calcified Tissues and Biomaterials, Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC H3C3J7, Canada; (R.d.B.e.L.B.); (K.J.P.); (A.P.D.); (D.G.B.)
| | - John B. Brunski
- Department of Surgery, School of Medicine, Stanford University, Stanford, CA 94305, USA;
| | - Antonio Nanci
- Laboratory for the Study of Calcified Tissues and Biomaterials, Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC H3C3J7, Canada; (R.d.B.e.L.B.); (K.J.P.); (A.P.D.); (D.G.B.)
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC H3C3J7, Canada
- Correspondence: ; Tel.: +1514-343-5846
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Tian Y, Li Z, Chen J, Yuan X, Sadowsky SJ, Coyac BR, Brunski JB, Helms JA. Mechano-adaptive Responses of Alveolar Bone to Implant Hyper-loading in a pre-clinical in vivo model. Clin Oral Implants Res 2020; 31:1159-1172. [PMID: 32882082 DOI: 10.1111/clr.13662] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 07/19/2020] [Accepted: 08/12/2020] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Oral implants transmit biting forces to peri-implant bone. In turn, those forces subject peri-implant bone to mechanical stresses and strains. Here, our objective was to understand how peri-implant bone responded to conditions of normal versus hyper-loading in a mouse model. MATERIAL AND METHODS Sixty-six mice were randomly assigned to 2 groups; both groups underwent bilateral maxillary first molar extraction followed by complete healing. Titanium alloy implants were placed in healed sites and positioned below the occlusal plane. After osseointegration, a composite crown was affixed to the implant so masticatory loading would ensue. In controls, the remaining dentition was left intact but in the hyper-loaded (test) group, the remaining molars were extracted. 3D finite element analysis (FEA) calculated peri-implant strains resulting from normal and hyper-loading. Peri-implant tissues were analyzed at multiple time points using micro-computed tomography (µCT) imaging, histology, enzymatic assays of bone remodeling, and vital dye labeling to evaluate bone accrual. RESULTS Compared to controls, hyper-loaded implants experienced a 3.6-fold increase in occlusal force, producing higher peri-implant strains. Bone formation and resorption were both significantly elevated around hyper-loaded implants, eventually culminating in a significant increase in peri-implant bone volume/total volume (BV/TV). In our mouse model, masticatory hyper-loading of an osseointegrated implant was associated with increased peri-implant strain, increased peri-implant bone remodeling, and a net gain in bone deposition. CONCLUSION Hyper-loading results in bone strain with catabolic and anabolic bone responses, leading to a net gain in bone deposition.
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Affiliation(s)
- Ye Tian
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Zhijun Li
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA.,Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinlong Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Xue Yuan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Steven J Sadowsky
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA.,Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, CA, USA
| | - Benjamin R Coyac
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
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Coyac BR, Leahy B, Li Z, Salvi G, Yin X, Brunski JB, Helms JA. Bone formation around unstable implants is enhanced by a WNT protein therapeutic in a preclinical in vivo model. Clin Oral Implants Res 2020; 31:1125-1137. [PMID: 32881143 DOI: 10.1111/clr.13659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/10/2020] [Accepted: 08/08/2020] [Indexed: 12/30/2022]
Abstract
OBJECTIVES Our objective was to test the hypothesis that local delivery of a WNT protein therapeutic would support osseointegration of an unstable implant placed into an oversized osteotomy and subjected to functional loading. MATERIALS AND METHODS Using a split-mouth design in an ovariectomized (OVX) rat model, 50 titanium implants were placed in oversized osteotomies. Implants were subjected to functional loading. One-half of the implants were treated with a liposomal formulation of WNT3A protein (L-WNT3A); the other half received an identical liposomal formulation containing phosphate-buffered saline (PBS). Finite element modeling estimated peri-implant strains caused by functional loading. Histological, molecular, cellular, and quantitative micro-computed tomographic (µCT) imaging analyses were performed on samples from post-implant days (PID) 3, 7, and 14. Lateral implant stability was quantified at PID 7 and 14. RESULTS Finite element analyses predicted levels of peri-implant strains incompatible with new bone formation. Micro-CT imaging, histological, and quantitative immunohistochemical (IHC) analyses confirmed that PBS-treated implants underwent fibrous encapsulation. In those cases where the peri-implant environment was treated with L-WNT3A, µCT imaging, histological, and quantitative IHC analyses demonstrated a significant increase in expression of proliferative (PCNA) and osteogenic (Runx2, Osterix) markers. One week after L-WNT3A treatment, new bone formation was evident, and two weeks later, L-WNT3A-treated gaps had a stiffer interface compared to PBS-treated gaps. CONCLUSION In a rat model, unstable implants undergo fibrous encapsulation. If the same unstable implants are treated with L-WNT3A at the time of placement, then it results in significantly more peri-implant bone and greater interfacial stiffness.
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Affiliation(s)
- Benjamin R Coyac
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Brian Leahy
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Zhijun Li
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Giuseppe Salvi
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Xing Yin
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - John B Brunski
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Jill A Helms
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
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8
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Sadowsky SJ, Brunski JB. Are teeth superior to implants? A mapping review. J Prosthet Dent 2020; 126:181-187. [PMID: 32862999 DOI: 10.1016/j.prosdent.2020.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 10/23/2022]
Abstract
STATEMENT OF PROBLEM There is a long-held assumption that teeth are superior to implants because the periodontal ligament (PDL) confers a preeminent defense against biologic and mechanical challenges. However, adequate analysis of the literature is lacking. As a result, differential treatment planning of tooth- and implant-supported restorations has been compromised. PURPOSE Given an abundance and diversity of research, the purpose of this mapping review was to identify basic scientific gaps in the knowledge of how teeth and implants respond to biologic and mechanical loads. The findings will offer enhanced evidence-based clinical decision-making when considering replacement of periodontally compromised teeth and the design of implant prostheses. MATERIAL AND METHODS The online databases PubMed, Science Direct, and Web of Science were searched. Published work from 1965 to 2020 was collected and independently analyzed by both authors for inclusion in this review. RESULTS A total of 108 articles met the inclusion criteria of clinical, in vivo, and in vitro studies in the English language on the periradicular and peri-implant bone response to biologic and mechanical loads. The qualitative analysis found that the PDL's enhanced vascularity, stem cell ability, and resident cells that respond to inflammation allow for a more robust defense against biologic threats compared with implants. While the suspensory PDL acts to mediate moderate loads to the bone, higher compressive stress and strain within the PDL itself can initiate a biologic sequence of osteoclastic activity that can affect changes in the adjacent bone. Conversely, the peri-implant bone is more resistant to similar loads and the threshold for overload is higher because of the absence of a stress or strain sensitivity inherent in the PDL. CONCLUSIONS Based on this mapping review, teeth are superior to implants in their ability to resist biologic challenges, but implants are superior to teeth in managing higher compressive loads without prompting bone resorption.
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Affiliation(s)
- Steven J Sadowsky
- Professor, Preventive and Restorative Department, University of the Pacific Arthur A. Dugoni School of Dentistry, San Francisco, Calif.
| | - John B Brunski
- Professor, Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, Calif
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9
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Pilawski I, Tulu US, Ticha P, Schüpbach P, Traxler H, Xu Q, Pan J, Coyac BR, Yuan X, Tian Y, Liu Y, Chen J, Erdogan Y, Arioka M, Armaro M, Wu M, Brunski JB, Helms JA. Interspecies Comparison of Alveolar Bone Biology, Part I: Morphology and Physiology of Pristine Bone. JDR Clin Trans Res 2020; 6:352-360. [PMID: 32660303 DOI: 10.1177/2380084420936979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
INTRODUCTION Few interspecies comparisons of alveolar bone have been documented, and this knowledge gap raises questions about which animal models most accurately represent human dental conditions or responses to surgical interventions. OBJECTIVES The objective of this study was to employ state-of-the-art quantitative metrics to directly assess and compare the structural and functional characteristics of alveolar bone among humans, mini pigs, rats, and mice. METHODS The same anatomic location (i.e., the posterior maxillae) was analyzed in all species via micro-computed tomographic imaging, followed by quantitative analyses, coupled with histology and immunohistochemistry. Bone remodeling was evaluated with alkaline phosphatase activity and tartrate-resistant acid phosphatase staining to identify osteoblast and osteoclast activities. In vivo fluorochrome labeling was used as a means to assess mineral apposition rates. RESULTS Collectively, these analyses demonstrated that bone volume differed among the species, while bone mineral density was equal. All species showed a similar density of alveolar osteocytes, with a highly conserved pattern of collagen organization. Collagen maturation was equal among mouse, rat, and mini pig. Bone remodeling was a shared feature among the species, with morphologically indistinguishable hemiosteonal appearances, osteocytic perilacunar remodeling, and similar mineral apposition rates in alveolar bone. CONCLUSIONS Our analyses demonstrated equivalencies among the 4 species in a plurality of the biological features of alveolar bone. Despite contradictory results from older studies, we found no evidence for the superiority of pig models over rodent models in representing human bone biology. KNOWLEDGE TRANSFER STATEMENT Animal models are extensively used to evaluate bone tissue engineering strategies, yet there are few state-of-the-art studies that rigorously compare and quantify the factors influencing selection of a given animal model. Consequently, there is an urgent need to assess preclinical animal models for their predictive value to dental research. Our article addresses this knowledge gap and, in doing so, provides a foundation for more effective standardization among animal models commonly used in dentistry.
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Affiliation(s)
- I Pilawski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - U S Tulu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - P Ticha
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - P Schüpbach
- Schupbach Ltd, Service and Research Laboratory, Thalwil, Switzerland
| | - H Traxler
- Center of Anatomy and Cell Biology, Division of Anatomy, Medical University of Vienna, Vienna, Austria
| | - Q Xu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - J Pan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - B R Coyac
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - X Yuan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - Y Tian
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - Y Liu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - J Chen
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - Y Erdogan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - M Arioka
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA.,Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - M Armaro
- Nobel Biocare Services AG, Zürich-Flughafen, Switzerland
| | - M Wu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - J B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
| | - J A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA, USA
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Turkkahraman H, Yuan X, Salmon B, Chen CH, Brunski JB, Helms JA. Root resorption and ensuing cementum repair by Wnt/β-catenin dependent mechanism. Am J Orthod Dentofacial Orthop 2020; 158:16-27. [DOI: 10.1016/j.ajodo.2019.06.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 06/01/2019] [Accepted: 06/01/2019] [Indexed: 02/02/2023]
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11
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Coyac BR, Sun Q, Leahy B, Salvi G, Yuan X, Brunski JB, Helms JA. Optimizing autologous bone contribution to implant osseointegration. J Periodontol 2020; 91:1632-1644. [PMID: 32279310 DOI: 10.1002/jper.19-0524] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 02/28/2020] [Accepted: 02/28/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND Autologous bone can be harvested from the flutes of a conventional drill or from a bone scraper; here we compared whether autologous bone chips generated by a new slow-speed instrument were more osteogenic than the bone chips generated by conventional drills or bone scrapers. Additionally, we tested whether the osteogenic potential of bone chips could be further improved by exposure to a Wnt signaling (WNT) therapeutic. METHODS Osteotomies were prepared in fresh rat maxillary first molar extraction sockets using a conventional drill or a new osseo-shaping instrument; titanium alloy implants were placed immediately thereafter. Using molecular/cellular and histologic analyses, the fates of the resulting bone chips were analyzed. To test whether increasing WNT signaling improved osteogenesis in an immediate post-extraction implant environment, a WNT therapeutic was introduced at the time of implant placement. RESULTS Bone collected from a conventional drill exhibited extensive apoptosis; in contrast, bone generated by the new instrument remained in situ, which preserved their viability. Also preserved was the viability of the osteoprogenitor cells attached to the bone chips. Exogenous treatment with a WNT therapeutic increased the rate of osteogenesis around immediate post-extraction implants. CONCLUSIONS Compared with conventional drills or bone scrapers, a new cutting instrument enabled concomitant site preparation with autologous bone chip collection. Histology/histomorphometric analyses revealed that the bone chips generated by this new tool were more osteogenic and could be further enhanced by exposure to a WNT therapeutic. Even though gaps still existed in placebo controls and liposomal WNT3A (L-WNT3A) cases, the area of peri-implant bone was significantly greater in L-WNT3A treated sites.
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Affiliation(s)
- Benjamin R Coyac
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - Qiang Sun
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA.,Department of Plastic Surgery, China Medical University Hospital, Shenyang, China
| | - Brian Leahy
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - Giuseppe Salvi
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - Xue Yuan
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - John B Brunski
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
| | - Jill A Helms
- Department of Plastic and Reconstructive Surgery, School of Medicine, Stanford University, Palo Alto, California, USA
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12
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Li Z, Arioka M, Liu Y, Aghvami M, Tulu S, Brunski JB, Helms JA. Effects of condensation and compressive strain on implant primary stability: A longitudinal, in vivo, multiscale study in mice. Bone Joint Res 2020; 9:60-70. [PMID: 32435456 PMCID: PMC7229305 DOI: 10.1302/2046-3758.92.bjr-2019-0161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Aims Surgeons and most engineers believe that bone compaction improves implant primary stability without causing undue damage to the bone itself. In this study, we developed a murine distal femoral implant model and tested this dogma. Methods Each mouse received two femoral implants, one placed into a site prepared by drilling and the other into the contralateral site prepared by drilling followed by stepwise condensation. Results Condensation significantly increased peri-implant bone density but it also produced higher strains at the interface between the bone and implant, which led to significantly more bone microdamage. Despite increased peri-implant bone density, condensation did not improve implant primary stability as measured by an in vivo lateral stability test. Ultimately, the condensed bone underwent resorption, which delayed the onset of new bone formation around the implant. Conclusion Collectively, these multiscale analyses demonstrate that condensation does not positively contribute to implant stability or to new peri-implant bone formation. Cite this article:Bone Joint Res. 2020;9(2):60–70.
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Affiliation(s)
- Zhijun Li
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, California, USA; Orthopedic surgeon, Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Masaki Arioka
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, California, USA; Assistant professor, Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yindong Liu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, California, USA; Oral surgeon, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Maziar Aghvami
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, California, USA
| | - Serdar Tulu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, California, USA
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, California, USA
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, California, USA
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13
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Coyac BR, Leahy B, Salvi G, Hoffmann W, Brunski JB, Helms JA. A preclinical model links osseo‐densification due to misfit and osseo‐destruction due to stress/strain. Clin Oral Implants Res 2019; 30:1238-1249. [DOI: 10.1111/clr.13537] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 09/05/2019] [Accepted: 09/05/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Benjamin R. Coyac
- Department of Plastic and Reconstructive Surgery School of Medicine Stanford University Palo Alto CA USA
| | - Brian Leahy
- Department of Plastic and Reconstructive Surgery School of Medicine Stanford University Palo Alto CA USA
| | - Giuseppe Salvi
- Department of Plastic and Reconstructive Surgery School of Medicine Stanford University Palo Alto CA USA
| | | | - John B. Brunski
- Department of Plastic and Reconstructive Surgery School of Medicine Stanford University Palo Alto CA USA
| | - Jill A. Helms
- Department of Plastic and Reconstructive Surgery School of Medicine Stanford University Palo Alto CA USA
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14
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Aghvami M, Brunski JB, Serdar Tulu U, Chen CH, Helms JA. A Thermal and Biological Analysis of Bone Drilling. J Biomech Eng 2019; 140:2682437. [PMID: 30029243 DOI: 10.1115/1.4040312] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Indexed: 11/08/2022]
Abstract
With the introduction of high-speed cutting tools, clinicians have recognized the potential for thermal damage to the material being cut. Here, we developed a mathematical model of heat transfer caused by drilling bones of different densities and validated it with respect to experimentally measured temperatures in bone. We then coupled these computational results with a biological assessment of cell death following osteotomy site preparation. Parameters under clinical control, e.g., drill diameter, rotational speed, and irrigation, along with patient-specific variables such as bone density were evaluated in order to understand their contributions to thermal damage. Predictions from our models provide insights into temperatures and thresholds that cause osteocyte death and that can ultimately compromise stability of an implant.
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Affiliation(s)
- Maziar Aghvami
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA 94304
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA 94304
| | - U Serdar Tulu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA 94304
| | - Chih-Hao Chen
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA 94304.,Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan 33305, Taiwan
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Stanford, CA 94304 e-mail:
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15
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Monje A, Ravidà A, Wang HL, Helms JA, Brunski JB. Relationship Between Primary/Mechanical and Secondary/Biological Implant Stability. Int J Oral Maxillofac Implants 2019; 34:s7-s23. [PMID: 31116830 DOI: 10.11607/jomi.19suppl.g1] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE This systematic review was prepared as part of the Academy of Osseointegration (AO) 2018 Summit, held August 8-10 in Oak Brook Hills, Illinois, to assess the relationship between the primary (mechanical) and secondary (biological) implant stability. MATERIALS AND METHODS Electronic and manual searches were conducted by two independent examiners in order to address the following issues. Meta-regression analyses explored the relationship between primary stability, as measured by insertion torque (IT) and implant stability quotient (ISQ), and secondary stability, by means of survival and peri-implant marginal bone loss (MBL). RESULTS Overall, 37 articles were included for quantitative assessment. Of these, 17 reported on implant stability using only resonance frequncy analysis (RFA), 11 used only IT data, 7 used a combination of RFA and IT, and 2 used only the Periotest. The following findings were reached: ·Relationship between primary and secondary implant stability: Strong positive statistically significant relationship (P < .001). ·Relationship between primary stability by means of ISQ and implant survival: No statistically significant relationship (P = .4). ·Relationship between IT and implant survival: No statistically significant relationship (P = .2). ·Relationship between primary stability by means of ISQ unit and MBL: No statistically significant relationship (P = .9). ·Relationship between IT and MBL: Positive statistically significant relationship (P = .02). ·Accuracy of methods and devices to assess implant stability: Insufficient data to address this issue. CONCLUSION Data suggest that primary/mechanical stability leads to more efficient achievement of secondary/biological stability, but the achievement of high primary stability might be detrimental for bone level stability. While current methods/devices for tracking implant stability over time can be clinically useful, a robust connection between existing stability metrics with implant survival remains inconclusive.
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16
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de Barros E Lima Bueno R, Dias AP, Ponce KJ, Brunski JB, Nanci A. System for application of controlled forces on dental implants in rat maxillae: Influence of the number of load cycles on bone healing. J Biomed Mater Res B Appl Biomater 2019; 108:965-975. [PMID: 31368244 PMCID: PMC7078813 DOI: 10.1002/jbm.b.34449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 07/03/2019] [Accepted: 07/13/2019] [Indexed: 12/26/2022]
Abstract
Experimental studies on the effect of micromotion on bone healing around implants are frequently conducted in long bones. In order to more closely reflect the anatomical and clinical environments around dental implants, and eventually be able to experimentally address load‐management issues, we have developed a system that allows initial stabilization, protection from external forces, and controlled axial loading of implants. Screw‐shaped implants were placed on the edentulous ridge in rat maxillae. Three loading regimens were applied to validate the system; case A no loading (unloaded implant) for 14 days, case B no loading in the first 7 days followed by 7 days of a single, daily loading session (60 cycles of an axial force of 1.5 N/cycle), and case C no loading in the first 7 days followed by 7 days of two such daily loading sessions. Finite element modeling of the peri‐implant compressive and tensile strains plus histological and immunohistochemical analyses revealed that in case B any tissue damage resulting from the applied force (and related interfacial strains) did not per se disturb bone healing, however, in case C, the accumulation of damage resulting from the doubling of loading sessions severely disrupted the process. These proof‐of‐principle results validate the applicability of our system for controlled loading, and provide new evidence on the importance of the number of load cycles applied on healing of maxillary bone.
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Affiliation(s)
- Renan de Barros E Lima Bueno
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada
| | - Ana P Dias
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada
| | - Katia J Ponce
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada
| | - John B Brunski
- Department of Surgery, School of Medicine, Stanford University, Stanford, California
| | - Antonio Nanci
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dental Medicine, Université de Montréal, Montreal, QC, Canada
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17
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Abstract
Despite an extensive literature documenting the adaptive changes of bones and ligaments to mechanical forces, our understanding of how tissues actually mount a coordinated response to physical loading is astonishingly inadequate. Here, using finite element (FE) modeling and an in vivo murine model, we demonstrate the stress distributions within the periodontal ligament (PDL) caused by occlusal hyperloading. In direct response, a spatially restricted pattern of apoptosis is triggered in the stressed PDL, the temporal peak of which is coordinated with a spatially restricted burst in PDL cell proliferation. This culminates in increased collagen deposition and a thicker, stiffer PDL that is adapted to its new hyperloading status. Meanwhile, in the adjacent alveolar bone, hyperloading activates bone resorption, the peak of which is followed by a bone formation phase, leading ultimately to an accelerated rate of mineral apposition and an increase in alveolar bone density. All of these adaptive responses are orchestrated by a population of Wnt-responsive stem/progenitor cells residing in the PDL and bone, whose death and revival are ultimately responsible for directly giving rise to new PDL fibers and new bone.
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Affiliation(s)
- Q Xu
- 1 The Affiliated Hospital of Qingdao University, College of Stomatology, Qingdao University, Qingdao, China.,2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - X Yuan
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - X Zhang
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA.,3 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - J Chen
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA.,3 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Shi
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - J B Brunski
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - J A Helms
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
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18
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Chen CH, Coyac BR, Arioka M, Leahy B, Tulu US, Aghvami M, Holst S, Hoffmann W, Quarry A, Bahat O, Salmon B, Brunski JB, Helms JA. A Novel Osteotomy Preparation Technique to Preserve Implant Site Viability and Enhance Osteogenesis. J Clin Med 2019; 8:jcm8020170. [PMID: 30717291 PMCID: PMC6406409 DOI: 10.3390/jcm8020170] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 01/26/2019] [Accepted: 01/27/2019] [Indexed: 12/27/2022] Open
Abstract
The preservation of bone viability at an osteotomy site is a critical variable for subsequent implant osseointegration. Recent biomechanical studies evaluating the consequences of site preparation led us to rethink the design of bone-cutting drills, especially those intended for implant site preparation. We present here a novel drill design that is designed to efficiently cut bone at a very low rotational velocity, obviating the need for irrigation as a coolant. The low-speed cutting produces little heat and, consequently, osteocyte viability is maintained. The lack of irrigation, coupled with the unique design of the cutting flutes, channels into the osteotomy autologous bone chips and osseous coagulum that have inherent osteogenic potential. Collectively, these features result in robust, new bone formation at rates significantly faster than those observed with conventional drilling protocols. These preclinical data have practical implications for the clinical preparation of osteotomies and alveolar bone reconstructive surgeries.
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Affiliation(s)
- Chih-Hao Chen
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
- Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan 33305, Taiwan.
| | - Benjamin R Coyac
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Masaki Arioka
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
- Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
| | - Brian Leahy
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - U Serdar Tulu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Maziar Aghvami
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Stefan Holst
- Nobel Biocare Services AG P.O. Box, CH-8058 Zürich-Flughafen, Switzerland.
- Department of Prosthodontics, School of Dentistry, Johann-Wolfgang Goethe University, Frankfurt, Germany.
| | - Waldemar Hoffmann
- Nobel Biocare Services AG P.O. Box, CH-8058 Zürich-Flughafen, Switzerland.
| | - Antony Quarry
- Nobel Biocare Services AG P.O. Box, CH-8058 Zürich-Flughafen, Switzerland.
| | - Oded Bahat
- Private Practice, Beverly Hills, CA 90210, USA.
| | - Benjamin Salmon
- Paris Descartes-Sorbonne Paris Cité University, EA2496, Montrouge, France.
- Dental Medicine Department, Bretonneau Hospital, HUPNVS, AP-HP, Paris 75018, France.
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
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19
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Chen CH, Wang L, Serdar Tulu U, Arioka M, Moghim MM, Salmon B, Chen CT, Hoffmann W, Gilgenbach J, Brunski JB, Helms JA. An osteopenic/osteoporotic phenotype delays alveolar bone repair. Bone 2018; 112:212-219. [PMID: 29704698 DOI: 10.1016/j.bone.2018.04.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/10/2018] [Accepted: 04/21/2018] [Indexed: 12/27/2022]
Abstract
Aging is associated with a function decline in tissue homeostasis and tissue repair. Aging is also associated with an increased incidence in osteopenia and osteoporosis, but whether these low bone mass diseases are a risk factor for delayed bone healing still remains controversial. Addressing this question is of direct clinical relevance for dental patients, since most implants are performed in older patients who are at risk of developing low bone mass conditions. The objective of this study was to assess how an osteopenic/osteoporotic phenotype affected the rate of new alveolar bone formation. Using an ovariectomized (OVX) rat model, the rates of tooth extraction socket and osteotomy healing were compared with age-matched controls. Imaging, along with molecular, cellular, and histologic analyses, demonstrated that OVX produced an overt osteoporotic phenotype in long bones, but only a subtle phenotype in alveolar bone. Nonetheless, the OVX group demonstrated significantly slower alveolar bone healing in both the extraction socket, and in the osteotomy produced in a healed extraction site. Most notably, osteotomy site preparation created a dramatically wider zone of dying and dead osteocytes in the OVX group, which was coupled with more extensive bone remodeling and a delay in the differentiation of osteoblasts. Collectively, these analyses demonstrate that the emergence of an osteoporotic phenotype delays new alveolar bone formation.
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Affiliation(s)
- Chih-Hao Chen
- Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan 33305, Taiwan; Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Liao Wang
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - U Serdar Tulu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Masaki Arioka
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Melika Maghazeh Moghim
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; University College London Medical School, University College London, London WC1E 6BT, UK
| | - Benjamin Salmon
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Paris Descartes University - Sorbonne Paris Cité, EA 2496 - Orofacial Pathologies, Imaging and Biotherapies Lab and Dental Medicine Department, Bretonneau Hospital, HUPNVS, AP-HP, Paris, France
| | - Chien-Tzung Chen
- Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan 33305, Taiwan; Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital at Keelung, Keelung 20401, Taiwan
| | - Waldemar Hoffmann
- Nobel Biocare Services AG P.O. Box, CH-8058 Zürich-Flughafen, Switzerland
| | - Jessica Gilgenbach
- Nobel Biocare Services AG P.O. Box, CH-8058 Zürich-Flughafen, Switzerland
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
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20
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de Barros E Lima Bueno R, Dias AP, Ponce KJ, Wazen R, Brunski JB, Nanci A. Bone healing response in cyclically loaded implants: Comparing zero, one, and two loading sessions per day. J Mech Behav Biomed Mater 2018; 85:152-161. [PMID: 29894930 PMCID: PMC6035061 DOI: 10.1016/j.jmbbm.2018.05.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 04/16/2018] [Accepted: 05/30/2018] [Indexed: 01/15/2023]
Abstract
When bone implants are loaded, they are inevitably subjected to displacement relative to bone. Such micro-motion generates stress/strain states at the interface that can cause beneficial or detrimental sequels. The objective of this study is to better understand the mechanobiology of bone healing at the tissue-implant interface during repeated loading. Machined screw shaped Ti implants were placed in rat tibiae in a hole slightly bigger than the implant diameter. Implants were held stable by a specially-designed bone plate that permits controlled loading. Three loading regimens were applied, (a) zero loading, (b) one daily loading session of 60 cycles with an axial force of 1.5 N/cycle for 7 days, and (c) two such daily sessions with the same axial force also for 7 days. Finite element analysis was used to characterize the mechanobiological conditions produced by the loading sessions. After 7 days, the implants with surrounding interfacial tissue were harvested and processed for histological, histomorphometric and DNA microarray analyses. Histomorphometric analyses revealed that the group subjected to repeated loading sessions exhibited a significant decrease in bone-implant contact and increase in bone-implant distance, as compared to unloaded implants and those subjected to only one loading session. Gene expression profiles differed during osseointegration between all groups mainly with respect to inflammatory and unidentified gene categories. The results indicate that increasing the daily cyclic loading of implants induces deleterious changes in the bone healing response, most likely due to the accumulation of tissue damage and associated inflammatory reaction at the bone-implant interface.
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Affiliation(s)
- Renan de Barros E Lima Bueno
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada
| | - Ana Paula Dias
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada
| | - Katia J Ponce
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada
| | - Rima Wazen
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada
| | - John B Brunski
- Department of Surgery, School of Medicine, Stanford University, Stanford, CA, United States
| | - Antonio Nanci
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculty of Dentistry, Université de Montréal, Montreal, QC, Canada.
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21
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Yuan X, Pei X, Zhao Y, Li Z, Chen CH, Tulu US, Liu B, Van Brunt LA, Brunski JB, Helms JA. Biomechanics of Immediate Postextraction Implant Osseointegration. J Dent Res 2018; 97:987-994. [PMID: 29608868 DOI: 10.1177/0022034518765757] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The aim of this study was to gain insights into the biology and mechanics of immediate postextraction implant osseointegration. To mimic clinical practice, murine first molar extraction was followed by osteotomy site preparation, specifically in the palatal root socket. The osteotomy was positioned such that it removed periodontal ligament (PDL) only on the palatal aspect of the socket, leaving the buccal aspect undisturbed. This strategy created 2 distinct peri-implant environments: on the palatal aspect, the implant was in direct contact with bone, while on the buccal aspect, a PDL-filled gap existed between the implant and bone. Finite element modeling showed high strains on the palatal aspect, where bone was compressed by the implant. Osteocyte death and bone resorption predominated on the palatal aspect, leading to the loss of peri-implant bone. On the buccal aspect, where finite element modeling revealed low strains, there was minimal osteocyte death and robust peri-implant bone formation. Initially, the buccal aspect was filled with PDL remnants, which we found directly provided Wnt-responsive cells that were responsible for new bone formation and osseointegration. On the palatal aspect, which was devoid of PDL and Wnt-responsive cells, adding exogenous liposomal WNT3A created an osteogenic environment for rapid peri-implant bone formation. Thus, we conclude that low strain and high Wnt signaling favor osseointegration of immediate postextraction implants. The PDL harbors Wnt-responsive cells that are inherently osteogenic, and if the PDL tissue is healthy, it is reasonable to preserve this tissue during immediate implant placement.
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Affiliation(s)
- X Yuan
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - X Pei
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA.,2 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Mainland China
| | - Y Zhao
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA.,3 Department of Oral Basic Science, School of Dentistry, Lanzhou University, Lanzhou, Mainland China
| | - Z Li
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA.,4 Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, Mainland China
| | - C H Chen
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA.,5 Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - U S Tulu
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - B Liu
- 6 Ankasa Regenerative Therapeutics, South San Francisco, CA, USA
| | - L A Van Brunt
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - J B Brunski
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - J A Helms
- 1 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA.,6 Ankasa Regenerative Therapeutics, South San Francisco, CA, USA
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22
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Li J, Yin X, Huang L, Mouraret S, Brunski JB, Cordova L, Salmon B, Helms JA. Relationships among Bone Quality, Implant Osseointegration, and Wnt Signaling. J Dent Res 2017; 96:822-831. [PMID: 28571512 DOI: 10.1177/0022034517700131] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A variety of clinical classification schemes have been proposed as a means to identify sites in the oral cavity where implant osseointegration is likely to be successful. Most schemes are based on structural characteristics of the bone, for example, the relative proportion of densely compact, homogenous (type I) bone versus more trabeculated, cancellous (type III) bone. None of these schemes, however, consider potential biological characteristics of the bone. Here, we employed multiscale analyses to identify and characterize type I and type III bones in murine jaws. We then combined these analytical tools with in vivo models of osteotomy healing and implant osseointegration to determine if one type of bone healed faster and supported osseointegration better than another. Collectively, these studies revealed a strong positive correlation between bone remodeling rates, mitotic activity, and osteotomy site healing in type III bone and high endogenous Wnt signaling. This positive correlation was strengthened by observations showing that the osteoid matrix that is responsible for implant osseointegration originates from Wnt-responsive cells and their progeny. The potential application of this knowledge to clinical practice is discussed, along with a theory unifying the role that biology and mechanics play in implant osseointegration.
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Affiliation(s)
- J Li
- 1 State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - X Yin
- 1 State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - L Huang
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA.,3 Department of Orthodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - S Mouraret
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J B Brunski
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - L Cordova
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA.,4 Department of Oral and Maxillofacial Surgery, School of Dentistry, University of Chile, Santiago, Chile
| | - B Salmon
- 5 EA 2496, Orofacial Pathologies, Imaging and Biothérapies Laboratoire, L'Université Paris Descartes, Sorbonne Paris Cité, Montrouge, France.,6 Le Service d'Odontologie de Bretonneau, Hôpitaux Universitaires Paris Nord Val de Seine, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - J A Helms
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
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23
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Wang L, Wu Y, Perez KC, Hyman S, Brunski JB, Tulu U, Bao C, Salmon B, Helms JA. Effects of Condensation on Peri-implant Bone Density and Remodeling. J Dent Res 2017; 96:413-420. [PMID: 28048963 DOI: 10.1177/0022034516683932] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Bone condensation is thought to densify interfacial bone and thus improve implant primary stability, but scant data substantiate either claim. We developed a murine oral implant model to test these hypotheses. Osteotomies were created in healed maxillary extraction sites 1) by drilling or 2) by drilling followed by stepwise condensation with tapered osteotomes. Condensation increased interfacial bone density, as measured by a significant change in bone volume/total volume and trabecular spacing, but it simultaneously damaged the bone. On postimplant day 1, the condensed bone interface exhibited microfractures and osteoclast activity. Finite element modeling, mechanical testing, and immunohistochemical analyses at multiple time points throughout the osseointegration period demonstrated that condensation caused very high interfacial strains, marginal bone resorption, and no improvement in implant stability. Collectively, these multiscale analyses demonstrate that condensation does not positively contribute to implant stability.
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Affiliation(s)
- L Wang
- 1 State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Y Wu
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA.,3 Orthodontic Department, Stomatology Hospital of Chongqing Medical University; Chongqing Key Laboratory of Oral Disease and Biomedical Sciences; Chongqing Municipal Key Laboratory, Chongqing, China
| | - K C Perez
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - S Hyman
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J B Brunski
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - U Tulu
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - C Bao
- 1 State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - B Salmon
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA.,4 EA 2496, Orofacial Pathologies, Imaging and Biotherapies Laboratory, Paris Descartes University-Sorbonne Paris Cité, Montrouge, France; and AP-HP Odontology Department Bretonneau, Hopitaux Universitaires Paris Nord Val de Seine, Paris, France
| | - J A Helms
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
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24
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Abstract
While bone healing occurs around implants, the extent to which this differs from healing at sites without implants remains unknown. We tested the hypothesis that an implant surface may affect the early stages of healing. In a new mouse model, we made cellular and molecular evaluations of healing at bone-implant interfaces vs. empty cortical defects. We assessed healing around Ti-6Al-4V, poly(L-lactide-co-D,L,-lactide), and 303 stainless steel implants with surface characteristics comparable with those of commercial implants. Our qualitative cellular and molecular evaluations showed that osteoblast differentiation and new bone deposition began sooner around the implants, suggesting that the implant surface and microenvironment around implants favored osteogenesis. The general stages of healing in this mouse model resembled those in larger animal models, and supported the use of this new model as a test bed for studying cellular and molecular responses to biomaterial and biomechanical conditions.
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Affiliation(s)
- C Colnot
- Department of Orthopaedic Surgery, University of California, San Francisco, CA 94110-1342, USA
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25
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Ransom RC, Hunter DJ, Hyman S, Singh G, Ransom SC, Shen EZ, Perez KC, Gillette M, Li J, Liu B, Brunski JB, Helms JA. Axin2-expressing cells execute regeneration after skeletal injury. Sci Rep 2016; 6:36524. [PMID: 27853243 PMCID: PMC5113299 DOI: 10.1038/srep36524] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 10/18/2016] [Indexed: 01/20/2023] Open
Abstract
The mammalian skeleton performs a diverse range of vital functions, requiring mechanisms of regeneration that restore functional skeletal cell populations after injury. We hypothesized that the Wnt pathway specifies distinct functional subsets of skeletal cell types, and that lineage tracing of Wnt-responding cells (WRCs) using the Axin2 gene in mice identifies a population of long-lived skeletal cells on the periosteum of long bone. Ablation of these WRCs disrupts healing after injury, and three-dimensional finite element modeling of the regenerate delineates their essential role in functional bone regeneration. These progenitor cells in the periosteum are activated upon injury and give rise to both cartilage and bone. Indeed, our findings suggest that WRCs may serve as a therapeutic target in the setting of impaired skeletal regeneration.
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Affiliation(s)
- R C Ransom
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA.,Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - D J Hunter
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - S Hyman
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - G Singh
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - S C Ransom
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - E Z Shen
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - K C Perez
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - M Gillette
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - J Li
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - B Liu
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - J B Brunski
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
| | - J A Helms
- Hagey Laboratory for Pediatric Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5148, USA
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26
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Yin X, Li J, Chen T, Mouraret S, Dhamdhere G, Brunski JB, Zou S, Helms JA. Rescuing failed oral implants via Wnt activation. J Clin Periodontol 2016; 43:180-92. [PMID: 26718012 DOI: 10.1111/jcpe.12503] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/24/2015] [Indexed: 02/05/2023]
Abstract
AIM Implant osseointegration is not always guaranteed and once fibrous encapsulation occurs clinicians have few options other than implant removal. Our goal was to test whether a WNT protein therapeutic could rescue such failed implants. MATERIAL AND METHODS Titanium implants were placed in over-sized murine oral osteotomies. A lack of primary stability was verified by mechanical testing. Interfacial strains were estimated by finite element modelling and histology coupled with histomorphometry confirmed the lack of peri-implant bone. After fibrous encapsulation was established peri-implant injections of a liposomal formulation of WNT3A protein (L-WNT3A) or liposomal PBS (L-PBS) were then initiated. Quantitative assays were employed to analyse the effects of L-WNT3A treatment. RESULTS Implants in gap-type interfaces exhibited high interfacial strains and no primary stability. After verification of implant failure, L-WNT3A or L-PBS injections were initiated. L-WNT3A induced a rapid, significant increase in Wnt responsiveness in the peri-implant environment, cell proliferation and osteogenic protein expression. The amount of peri-implant bone and bone in contact with the implant were significantly higher in L-WNT3A cases. CONCLUSIONS These data demonstrate L-WNT3A can induce peri-implant bone formation even in cases where fibrous encapsulation predominates.
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Affiliation(s)
- Xing Yin
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - Jingtao Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - Tao Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - Sylvain Mouraret
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - Girija Dhamdhere
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - Shujuan Zou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
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27
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Helms JA, Brunski JB. Response to Letter to the Editor, "Multiscale Analyses of the Bone-implant Interface". J Dent Res 2015; 94:1783. [PMID: 26316462 DOI: 10.1177/0022034515603925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- J A Helms
- Division of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA, USA
| | - J B Brunski
- Division of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA, USA
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28
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Abstract
Implants placed with high insertion torque (IT) typically exhibit primary stability, which enables early loading. Whether high IT has a negative impact on peri-implant bone health, however, remains to be determined. The purpose of this study was to ascertain how peri-implant bone responds to strains and stresses created when implants are placed with low and high IT. Titanium micro-implants were inserted into murine femurs with low and high IT using torque values that were scaled to approximate those used to place clinically sized implants. Torque created in peri-implant tissues a distribution and magnitude of strains, which were calculated through finite element modeling. Stiffness tests quantified primary and secondary implant stability. At multiple time points, molecular, cellular, and histomorphometric analyses were performed to quantitatively determine the effect of high and low strains on apoptosis, mineralization, resorption, and collagen matrix deposition in peri-implant bone. Preparation of an osteotomy results in a narrow zone of dead and dying osteocytes in peri-implant bone that is not significantly enlarged in response to implants placed with low IT. Placing implants with high IT more than doubles this zone of dead and dying osteocytes. As a result, peri-implant bone develops micro-fractures, bone resorption is increased, and bone formation is decreased. Using high IT to place an implant creates high interfacial stress and strain that are associated with damage to peri-implant bone and therefore should be avoided to best preserve the viability of this tissue.
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Affiliation(s)
- J Y Cha
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA Orthodontic Department, College of Dentistry, Yonsei University, Seoul, South Korea
| | - M D Pereira
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - A A Smith
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - K S Houschyar
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - X Yin
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA State Key Laboratory of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - S Mouraret
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - J B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - J A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
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29
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Li J, Johnson CA, Smith AA, Shi B, Brunski JB, Helms JA. Molecular mechanisms underlying skeletal growth arrest by cutaneous scarring. Bone 2014; 66:223-31. [PMID: 24933346 DOI: 10.1016/j.bone.2014.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 03/11/2014] [Accepted: 06/03/2014] [Indexed: 02/06/2023]
Abstract
In pediatric surgeries, cutaneous scarring is frequently accompanied by an arrest in skeletal growth. The molecular mechanisms responsible for this effect are not understood. Here, we investigated the relationship between scar contracture and osteogenesis. An excisional cutaneous wound was made on the tail of neonatal mice. Finite element (FE) modeling of the wound site was used to predict the distribution and magnitude of contractile forces within soft and hard tissues. Morphogenesis of the bony vertebrae was monitored by micro-CT analyses, and vertebral growth plates were interrogated throughout the healing period using assays for cell proliferation, death, differentiation, as well as matrix deposition and remodeling. Wound contracture was grossly evident on post-injury day 7 and accompanying it was a significant shortening in the tail. FE modeling indicated high compressive strains localized to the dorsal portions of the vertebral growth plates and intervertebral disks. These predicted strain distributions corresponded to sites of increased cell death, a cessation in cell proliferation, and a loss in mineralization within the growth plates and IVD. Although cutaneous contracture resolved and skeletal growth rates returned to normal, vertebrae under the cutaneous wound remained significantly shorter than controls. Thus, localized contractile forces generated by scarring led to spatial alterations in cell proliferation, death, and differentiation that inhibited bone growth in a location-dependent manner. Resolution of cutaneous scarring was not accompanied by compensatory bone growth, which left the bony elements permanently truncated. Therefore, targeting early scar reduction is critical to preserving pediatric bone growth after surgery.
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Affiliation(s)
- Jingtao Li
- Department of Oral and Maxillofacial Surgery, West China Stomatology Hospital, Chengdu 610041, China; Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford CA 94035, USA
| | - Chelsey A Johnson
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford CA 94035, USA; College of Medicine, University of Arizona, Tucson, AZ 85719, USA
| | - Andrew A Smith
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford CA 94035, USA
| | - Bing Shi
- Department of Oral and Maxillofacial Surgery, West China Stomatology Hospital, Chengdu 610041, China
| | - John B Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford CA 94035, USA
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford CA 94035, USA.
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30
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Brunski JB. Biomechanical aspects of the optimal number of implants to carry a cross-arch full restoration. Eur J Oral Implantol 2014; 7 Suppl 2:S111-S131. [PMID: 24977245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A proper definition of the 'optimal' number of implants to support a full arch prosthesis should go beyond solely a listing of the number of implants used in a treatment plan; it should be based upon a biomechanical analysis that takes into account several factors: the locations of the implants in the jaw; the quality and quantity of bone into which they are placed; the loads (forces and moments) that develop on the implants; the magnitudes of stress and strain that develop in the interfacial bone as well as in the implants and prosthesis; and the relationship of the stresses and strains to limits for the materials involved. Overall, determining an 'optimal' number of implants to use in a patient is a biomechanical design problem. This paper discusses some of the approaches that are already available to aid biomechanically focused clinical treatment planning. A number of examples are presented to illustrate how relatively simple biomechanical analyses - e.g. the Skalak model - as well as more complex analyses (e.g. finite element modelling) can be used to assess the pros and cons of various arrangements of implants to support fullarch prostheses. Some of the examples considered include the use of 4 rather than 6 implants to span the same arc-length in a jaw, and the pros and cons of using tilted implants as in the 'all-on-4' approach. In evaluating the accuracy of the various biomechanical analyses, it is clear that our current prediction methods are not always perfectly accurate in vivo, although they can provide a reasonably approximate analysis of a treatment plan in many situations. In the current era of cone beam computerised tomography (CT) scans of patients in the dental office, there is significant promise for finite element analyses (FEA) based on anatomically-accurate input data. However, at the same time it has to be recognised that effective use of FEA software requires a reasonable engineering background, especially insofar as interpretations of the clinical significance of stresses and strains in bone and prosthetic materials.
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31
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Mouraret S, Hunter DJ, Bardet C, Popelut A, Brunski JB, Chaussain C, Bouchard P, Helms JA. Improving oral implant osseointegration in a murine model via Wnt signal amplification. J Clin Periodontol 2013; 41:172-80. [PMID: 24164629 DOI: 10.1111/jcpe.12187] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2013] [Indexed: 11/28/2022]
Abstract
AIM To determine the key biological events occurring during implant failure and then we use this knowledge to develop new biology-based strategies that improve osseointegration. MATERIALS AND METHODS Wild-type and Axin2(LacZ/LacZ) adult male mice underwent oral implant placement, with and without primary stability. Peri-implant tissues were evaluated using histology, alkaline phosphatase (ALP) activity, tartrate resistant acid phosphatase (TRAP) activity and TUNEL staining. In addition, mineralization sites, collagenous matrix organization and the expression of bone markers in the peri-implant tissues were assessed. RESULTS Maxillary implants lacking primary stability show histological evidence of persistent fibrous encapsulation and mobility, which recapitulates the clinical problems of implant failure. Despite histological and molecular evidence of fibrous encapsulation, osteoblasts in the gap interface exhibit robust ALP activity. This mineralization activity is counteracted by osteoclast activity that resorbs any new bony matrix and consequently, the fibrous encapsulation remains. Using a genetic mouse model, we show that implants lacking primary stability undergo osseointegration, provided that Wnt signalling is amplified. CONCLUSIONS In a mouse model of oral implant failure caused by a lack of primary stability, we find evidence of active mineralization. This mineralization, however, is outpaced by robust bone resorption, which culminates in persistent fibrous encapsulation of the implant. Fibrous encapsulation can be prevented and osseointegration assured if Wnt signalling is elevated at the time of implant placement.
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Affiliation(s)
- Sylvain Mouraret
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA; Department of Periodontology, Service of Odontology, Rothschild Hospital, AP-HP, Paris 7 - Denis, Diderot University, U.F.R. of Odontology, Paris, France
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32
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Wazen RM, Kuroda S, Nishio C, Sellin K, Brunski JB, Nanci A. Gene expression profiling and histomorphometric analyses of the early bone healing response around nanotextured implants. Nanomedicine (Lond) 2013; 8:1385-95. [PMID: 23286527 DOI: 10.2217/nnm.12.167] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED While in vitro studies have shown that nanoscale surface modifications influence cell fate and activity, there is little information on how they modulate healing at the bone-implant interface. AIM This study aims to investigate the effect of nanotopography at early time intervals when critical events for implant integration occur. MATERIALS & METHODS Untreated and sulfuric acid/hydrogen peroxide-treated machined-surface titanium alloy implants were placed in rat tibiae. Samples were processed for DNA microarray analysis and histomorphometry. RESULTS At both 3 and 5 days, the gene expression profile of the healing tissue around nanotextured implants differed from that around machined-surface implants or control empty holes, and were accompanied by an increase in bone-implant contact on day 5. While some standard pathways such as the immune response predominated, a number of unclassified genes were also implicated. CONCLUSION Nanotexture elicits an initial gene response that is more complex than suspected so far and favors healing at the bone-implant interface.
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Affiliation(s)
- Rima M Wazen
- Laboratory for the Study of Calcified Tissues & Biomaterials, Department of Stomatology, Université de Montréal, PO Box 6128, Station Centre-Ville, Montreal, QC, H3C 3J7, Canada
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Abramson S, Ackermann DM, Akins R, Anders R, Andersen PJ, Anderson JM, Ankrum JA, Anseth KS, Antonucci J, Atzet S, Badylak SF, Baura GD, Bellamkonda RV, Best SM, Bhumiratana S, Bianco RW, Bokros JC, Borovetz HS, Boskey AL, Brown JL, Brown BN, Brown SA, Brunski JB, Cahn F, Ritchie AC, Caplan AI, Carpenedo RL, Chilkoti A, Chung S, Cimetta E, Cleary G, Clements IP, Colas A, Coleman KP, Conway DE, Cooper SL, Costerton B, Coury AJ, Cunanan C, Curtis J, D’Amore A, DeMeo P, Desai TA, Dickens S, Domingo G, Duncan E, Eskin SG, Feigal DW, Ferreira L, Fuller J, Gallegos RP, Gawalt E, Ghosh K, Ghosn B, Gilbert TW, Glaser DE, Godier-Furnemont A, Gombotz WR, Grainger DW, Grunkemeier GL, Hacking SA, Hallab NJ, Hall-Stoodley L, Hanson SR, Haubold AD, Hauch KD, Hawkins KR, Heath DE, Helm DL, Hench LL, Hensten A, Hill RT, Hobson C, Hoerstrup SP, Hoffman AS, Horbett TA, Hubbell JA, Humayun MS, Ideker R, Ingber DE, Jain R, Jacob J, Jacobs JJ, Jacobsen N, Jin R, Johnson RJ, Karp JM, Kasper FK, Kathju S, Khademhosseini A, Kim S, King MW, Kleiner LW, Kohn J, Koschwanez HE, Kumbar SG, Kuo CK, LaFleur L, Lahti MT, Lambert B, Langer R, Laurencin CT, Lee-Parritz D, Lemons JE, Levin M, Levy RJ, Lewerenz GM, Li WJ, Lin CC, Liu F, Lowrie WG, Lu Y, Lysaght MJ, Maidhof R, Mansbridge J, Cristina M, Martins L, Martin J, Mayesh JP, McDevitt TC, McIntire LV, Merrit K, Migliaresi C, Mikos AG, Misch CE, Mitchell RN, More RB, Moss CW, Munson JM, Navarro M, Nerem RM, Ogawa R, Orgill BD, Orgill DP, Padera RF, Pandit A, Park K, Patel AS, Peck RB, Peckham PH, Peppas NA, Pereira MN, Planell J, Popat KC, Prestwich GD, Pun SH, Rabolt J, Rainbow RS, Rajab T, Ratner BD, Reichert WM, Rivard AL, Rowley AP, Ruan G, Sacks M, Sarkar D, Schaefer S, Schmidt CE, Schoen FJ, Schutte SC, Sefton MV, Shalaby SW, Shirtliff M, Simon MA, Singh M, Slack SM, Spelman FA, Starr A, Stayton PS, Steinert R, Stoodley P, Suri S, Swi Chang TM, Tandon N, Tanguay AR, Taylor MS, Teo GS, Thodeti CK, Tolkoff J, Treiser M, Tuan RS, Tucker EI, Venugopalan R, Vicari AR, Viney C, Voight JM, Vunjak-Novakovic G, Wagner WR, Wang L, Wasiluk KR, Watts DC, Weigl BH, Weiland JD, Whalen JJ, Williams DF, Williams RL, Wilson JT, Wilson CG, Winter J, Wolf MF, Wright JC, Yager P, Zhao W. Contributors. Biomater Sci 2013. [DOI: 10.1016/b978-0-08-087780-8.00150-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Leucht P, Monica SD, Temiyasathit S, Lenton K, Manu A, Longaker MT, Jacobs CR, Spilker RL, Guo H, Brunski JB, Helms JA. Primary cilia act as mechanosensors during bone healing around an implant. Med Eng Phys 2012; 35:392-402. [PMID: 22784673 DOI: 10.1016/j.medengphy.2012.06.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/26/2012] [Accepted: 06/03/2012] [Indexed: 01/05/2023]
Abstract
The primary cilium is an organelle that senses cues in a cell's local environment. Some of these cues constitute molecular signals; here, we investigate the extent to which primary cilia can also sense mechanical stimuli. We used a conditional approach to delete Kif3a in pre-osteoblasts and then employed a motion device that generated a spatial distribution of strain around an intra-osseous implant positioned in the mouse tibia. We correlated interfacial strain fields with cell behaviors ranging from proliferation through all stages of osteogenic differentiation. We found that peri-implant cells in the Col1Cre;Kif3a(fl/fl) mice were unable to proliferate in response to a mechanical stimulus, failed to deposit and then orient collagen fibers to the strain fields caused by implant displacement, and failed to differentiate into bone-forming osteoblasts. Collectively, these data demonstrate that the lack of a functioning primary cilium blunts the normal response of a cell to a defined mechanical stimulus. The ability to manipulate the genetic background of peri-implant cells within the context of a whole, living tissue provides a rare opportunity to explore mechanotransduction from a multi-scale perspective.
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Affiliation(s)
- P Leucht
- Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Popelut A, Rooker SM, Leucht P, Medio M, Brunski JB, Helms JA. The acceleration of implant osseointegration by liposomal Wnt3a. Biomaterials 2010; 31:9173-81. [PMID: 20864159 DOI: 10.1016/j.biomaterials.2010.08.045] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 08/19/2010] [Indexed: 11/29/2022]
Abstract
The strength of a Wnt-based strategy for tissue regeneration lies in the central role that Wnts play in healing. Tissue injury triggers local Wnt activation at the site of damage, and this Wnt signal is required for the repair and/or regeneration of almost all tissues including bone, neural tissues, myocardium, and epidermis. We developed a biologically based approach to create a transient elevation in Wnt signaling in peri-implant tissues, and in doing so, accelerated bone formation around the implant. Our subsequent molecular and cellular analyses provide mechanistic insights into the basis for this pro-osteogenic effect. Given the essential role of Wnt signaling in bone formation, this protein-based approach may have widespread application in implant osseointegration.
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Affiliation(s)
- Antoine Popelut
- Department of Periodontology, Service of Odontology, Hotel-Dieu Hospital, AP-HP, U.F.R. of Odontology, Paris 7 Denis Diderot University, Paris, France
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Leucht P, Kim JB, Wazen R, Currey JA, Nanci A, Brunski JB, Helms JA. Effect of mechanical stimuli on skeletal regeneration around implants. Bone 2007; 40:919-30. [PMID: 17175211 PMCID: PMC1987325 DOI: 10.1016/j.bone.2006.10.027] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Revised: 10/19/2006] [Accepted: 10/31/2006] [Indexed: 01/14/2023]
Abstract
Due to the aging population and the increasing need for total joint replacements, osseointegration is of a great interest for various clinical disciplines. Our objective was to investigate the molecular and cellular foundation that underlies this process. Here, we used an in vivo mouse model to study the cellular and molecular response in three distinct areas of unloaded implants: the periosteum, the gap between implant and cortical bone, and the marrow space. Our analyses began with the early phases of healing, and continued until the implants were completely osseointegrated. We investigated aspects of osseointegration ranging from vascularization, cell proliferation, differentiation, and bone remodeling. In doing so, we gained an understanding of the healing mechanisms of different skeletal tissues during unloaded implant osseointegration. To continue our analysis, we used a micromotion device to apply a defined physical stimulus to the implants, and in doing so, we dramatically enhanced bone formation in the peri-implant tissue. By comparing strain measurements with cellular and molecular analyses, we developed an understanding of the correlation between strain magnitudes and fate decisions of cells shaping the skeletal regenerate.
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Affiliation(s)
- Philipp Leucht
- Department of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA 94305, USA
- Department of Trauma, Hand and Reconstructive Surgery, Johann-Wolfgang-Goethe University of Frankfurt/Main, 60590 Frankfurt/Main, Germany
| | - Jae-Beom Kim
- Department of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA 94305, USA
| | - Rima Wazen
- Départment de stomatologic, Faculté de médecine dentaire, Montréal, Québec, Canada H3C 3J7
| | - Jennifer A. Currey
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Antonio Nanci
- Départment de stomatologic, Faculté de médecine dentaire, Montréal, Québec, Canada H3C 3J7
| | - John B. Brunski
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Jill A. Helms
- Department of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA 94305, USA
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Abstract
This study employed an optical strain measurement method, called microdisplacements by machine vision photogrammetry (DISMAP), to measure both the global and local strain fields in microtensile specimens of cortical bone subjected to controlled uniaxial tension. The variation of local maximum principal strains was measured within the gauge region of samples as a function of applied tensile stress during testing. High gradients of local strain appeared around microstructural features in stressed bone even while the global strain for the entire gauge region showed a strong linear correlation with increasing tensile stress (r2 = 0.98, p < 0.0001). The highest local strain around micro-structural features in bone was 11.5-79.5 times higher than the global strain.
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Affiliation(s)
- D G Kim
- Department of Mechanical Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA.
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Abstract
BACKGROUND Clinicians need quality research data to decide which dental implant should be selected for patient treatment. AIM(S)/OBJECTIVE(S): To present the scientific evidence for claims of relationship between characteristics of dental implants and clinical performance. STUDY DESIGN Systematic search of promotional material and Internet sites to find claims of implant superiority related to specific characteristics of the implant, and of the dental research literature to find scientific support for the claims. MAIN OUTCOME MEASURES Critical appraisal of the research documentation to establish the scientific external and internal validity as a basis for the likelihood of reported treatment outcomes as a function of implant characteristics. RESULTS More than 220 implant brands have been identified, produced by about 80 manufacturers. The implants are made from different materials, undergo different surface treatments and come in different shapes, lengths, widths and forms. The dentist can in theory choose among more than 2,000 implants in a given patient treatment situation. Implants made from titanium and titanium alloys appear to perform well clinically in properly surgically prepared bone, regardless of small variations of shapes and forms. Various surface treatments are currently being developed to improve the capacity of a more rapid anchorage of the implant into bone. A substantial number of claims made by different manufacturers on alleged superiority due to design characteristics are not based on sound and long-term clinical scientific research. Implants are, in some parts of the world, manufactured and sold with no demonstration of adherence to any international standards. CONCLUSIONS The scientific literature does not provide any clear directives to claims of alleged benefits of specific morphological characteristics of dental implants.
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Affiliation(s)
- Asbjørn Jokstad
- Institute of Clinical Dentistry, University of Oslo, Blindern, Norway.
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Brunski JB. Biomechanical aspects of oral/maxillofacial implants. INT J PROSTHODONT 2003; 16 Suppl:30-2; discussion 47-51. [PMID: 14661702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Affiliation(s)
- John B Brunski
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
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Porter JA, Petropoulos VC, Brunski JB. Comparison of load distribution for implant overdenture attachments. Int J Oral Maxillofac Implants 2002; 17:651-62. [PMID: 12381065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
PURPOSE The aim of this study was to compare the force and moment distributions that develop on different implant overdenture attachments when vertical compressive forces are applied to an implant-retained overdenture. MATERIALS AND METHODS The following attachments were examined: Nobel Biocare bar and clip (NBC), Nobel Biocare standard ball (NSB), Nobel Biocare 2.25-mm-diameter ball (NB2), Zest Anchor Advanced Generation (ZAAG), Sterngold ERA white (SEW), Sterngold ERA orange (SEO), Compliant Keeper System with titanium shims (CK-Ti), Compliant Keeper System with black nitrile 2SR90 sleeve rings (CK-70), and Compliant Keeper System with clear silicone 2SR90 sleeve rings (CK-90). The attachments were tested using custom strain-gauged abutments and 2 Brånemark System implants placed in a test model. Each attachment type had one part embedded in a denture-like housing and the other part (the abutment) screwed into the implants. Compressive static loads of 100 N were applied (1) bilaterally, over the distal midline (DM); (2) unilaterally, over the right implant (RI); (3) unilaterally, over the left implant (LI); and (4) between implants in the mid-anterior region (MA). Both the force and bending moment on each implant were recorded for each loading location and attachment type. Results were analyzed using 2-way analysis of variance and the Duncan multiple-range test. RESULTS Both loading location and attachment type were statistically significant factors (P < .05). In general, the force and moment on an implant were greater when the load was applied directly over the implant or at MA. DISCUSSION While not significant at every loading location, the largest implant forces tended to occur with ZAAG attachments; the smallest were found with the SEW, the SEO, the NSB, the CK-70, and the CK-90. Typically, higher moments existed for NBC and ZAAG, while lower moments existed for SEW, SEO, NSB, CK-90, and CK-70. CONCLUSION For different loading locations, significant differences were found among the different overdenture attachment systems.
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Affiliation(s)
- Joseph A Porter
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
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Ledet EH, Sachs BL, Brunski JB, Gatto CE, Donzelli PS. Real-time in vivo loading in the lumbar spine: part 1. Interbody implant: load cell design and preliminary results. Spine (Phila Pa 1976) 2000; 25:2595-600. [PMID: 11034643 DOI: 10.1097/00007632-200010150-00009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Instrumented interbody implants were placed into the disc space of a motion segment in two baboons. During the animal's activities, implants directly measured in vivo loads in the lumbar spine by telemetry transmitter. OBJECTIVES Develop and test an interbody implant-load cell and use the implant to measure directly loads imposed on the lumbar spine of the baboon, a semiupright animal. SUMMARY OF BACKGROUND DATA In vivo forces in the lumbar spine have been estimated using body weight calculations, moment arm models, dynamic chain models, electromyogram measurements, and intervertebral disc pressure measurements. METHODS An analytical model was used to determine the force-strain relation in a customized interbody implant. After validation by finite element modeling, strain gauges were mounted onto the implant and connected to a telemetry transmitter. Implants were placed surgically into the L4-L5 disc space of skeletally mature baboons and the transmitter in the flank. After surgery, load data were collected from the animals during activities. Radiographs were taken monthly to assess fusion. RESULTS The implant-load cell is sufficiently sensitive to monitor dynamic changes in strain and load. During extreme activity, highest measurable strain values were indicative of loads in excess of 2.8 times body weight. CONCLUSIONS The study technique and technology are efficacious for measuring real-time in vivo loads in the spine. Measuring load on an intradiscal implant over the course of healing provides key information about the mechanics of this process. Loads may be used to indicate performance demands on the intervertebral disc and interbody implants for subsequent implant design.
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Affiliation(s)
- E H Ledet
- Division of Orthopaedic Surgery, Albany Medical College, Albany, New York 12208, USA.
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Brunski JB, Puleo DA, Nanci A. Biomaterials and biomechanics of oral and maxillofacial implants: current status and future developments. Int J Oral Maxillofac Implants 2000; 15:15-46. [PMID: 10697938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Research in biomaterials and biomechanics has fueled a large part of the significant revolution associated with osseointegrated implants. Additional key areas that may become even more important--such as guided tissue regeneration, growth factors, and tissue engineering--could not be included in this review because of space limitations. All of this work will no doubt continue unabated; indeed, it is probably even accelerating as more clinical applications are found for implant technology and related therapies. An excellent overall summary of oral biology and dental implants recently appeared in a dedicated issue of Advances in Dental Research. Many advances have been made in the understanding of events at the interface between bone and implants and in developing methods for controlling these events. However, several important questions still remain. What is the relationship between tissue structure, matrix composition, and biomechanical properties of the interface? Do surface modifications alter the interfacial tissue structure and composition and the rate at which it forms? If surface modifications change the initial interface structure and composition, are these changes retained? Do surface modifications enhance biomechanical properties of the interface? As current understanding of the bone-implant interface progresses, so will development of proactive implants that can help promote desired outcomes. However, in the midst of the excitement born out of this activity, it is necessary to remember that the needs of the patient must remain paramount. It is also worth noting another as-yet unsatisfied need. With all of the new developments, continuing education of clinicians in the expert use of all of these research advances is needed. For example, in the area of biomechanical treatment planning, there are still no well-accepted biomaterials/biomechanics "building codes" that can be passed on to clinicians. Also, there are no readily available treatment-planning tools that clinicians can use to explore "what-if" scenarios and other design calculations of the sort done in modern engineering. No doubt such approaches could be developed based on materials already in the literature, but unfortunately much of what is done now by clinicians remains empirical. A worthwhile task for the future is to find ways to more effectively deliver products of research into the hands of clinicians.
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Affiliation(s)
- J B Brunski
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA.
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Abstract
Since dental implants must withstand relatively large forces and moments in function, a better understanding of in vivo bone response to loading would aid implant design. The following topics are essential in this problem. (1) Theoretical models and experimental data are available for understanding implant loading as an aid to case planning. (2) At least for several months after surgery, bone healing in gaps between implant and bone as well as in pre-existing damaged bone will determine interface structure and properties. The ongoing healing creates a complicated environment. (3) Recent studies reveal that an interfacial cement line exists between the implant surface and bone for titanium and hydroxyapatite (HA). Since cement lines in normal bone have been identified as weak interfaces, a cement line at a bone-biomaterial interface may also be a weak point. Indeed, data on interfacial shear and tensile "bond" strengths are consistent with this idea. (4) Excessive interfacial micromotion early after implantation interferes with local bone healing and predisposes to a fibrous tissue interface instead of osseointegration. (5) Large strains can damage bone. For implants that have healed in situ for several months before being loaded, data support the hypothesis that interfacial overload occurs if the strains are excessive in interfacial bone. While bone "adaptation" to loading is a long-standing concept in bone physiology, researchers may sometimes be too willing to accept this paradigm as an exclusive explanation of in vivo tissue responses during experiments, while overlooking confounding variables, alternative (non-mechanical) explanations, and the possibility that different types of bone (e.g., woven bone, Haversian bone, plexiform bone) may have different sensitivities to loading under healing vs. quiescent conditions.
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Affiliation(s)
- J B Brunski
- Department of Biomedical Engineering, Room 7040, Jonsson Engineering Center, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, USA
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Brunski JB. Mechanical properties of trabecular bone in the human mandible: implications for dental implant treatment planning and surgical placement. J Oral Maxillofac Surg 1999. [DOI: 10.1016/s0278-2391(99)90438-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
For load-bearing calcium-phosphate biomaterials, it is important to understand the relative contributions of direct physical-chemical bonding vs. mechanical interlocking to interfacial strength. In the limit of a perfectly smooth hydroxyapatite (HA) surface, a tensile test of the bone-HA interface affords an opportunity to isolate the bonding contribution related to HA surface chemistry alone. This study measured the bone-HA interfacial tensile strength for highly polished (approximately 0.05 micron alumina) dense HA disks (5.25 mm in diameter, 1.3 in mm thickness) in rabbit tibiae. Each of five rabbits received four HA disks, two per proximal tibia. Pull-off loads ranged from 3.14 +/- 2.38N at 55 days after implantation to 18.35 +/- 11.9N at 88 days; nominal interfacial tensile strengths were 0.15 +/- 0.11 MPa and 0.85 +/- 0.55 MPa, respectively. SEM of failed interfaces revealed failures between HA and bone, within the HA itself and within adjacent bone. Tissue remnants on HA were identified as mineralized bone with either a lamellar or trabecular structure. Oriented collagen fibers in the bone intricately interdigitated with the HA surface, which frequently showed breakdown at material grain boundaries and a rougher surface than originally implanted. Mechanical interlocking could not be eliminated as a mode of tissue attachment and contribution to bone-HA bonding, even after implanting an extremely smooth HA surface.
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Affiliation(s)
- J T Edwards
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA
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Elias JJ, Brunski JB, Scarton HA. A dynamic modal testing technique for noninvasive assessment of bone-dental implant interfaces. Int J Oral Maxillofac Implants 1996; 11:728-34. [PMID: 8990633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A dynamic modal testing technique has been developed to noninvasively assess the interface surrounding an endosseous dental implant with a lateral tap from an impedance head hammer. The technique assesses the rotational stiffness of the interface based on the shape of the power spectrum of the force-time curve produced on impact. In vitro experiments were performed to determine the sensitivity of the technique for detecting clinically relevant structural differences between interfaces. The modal test data were able to distinguish interfaces based on the type of bone at the interface and the degree of fixation between the implant and the interface.
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Affiliation(s)
- J J Elias
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
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Carr AB, Brunski JB, Hurley E. Effects of fabrication, finishing, and polishing procedures on preload in prostheses using conventional "gold' and plastic cylinders. Int J Oral Maxillofac Implants 1996; 11:589-98. [PMID: 8908856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
This study reviews fundamental concepts related to the use of screws and presents data describing the effect of fabrication, finishing, and polishing procedures on as-received preload for implant cylinders. Specifically, this study measured and compared preload produced when using as-received gold cylinders (the reference or gold standard), and cast cylinders produced from premade gold and plastic cylinders in the as-cast condition and following postcast finishing and polishing manipulations. The results reveal that preload in the gold screw-gold cylinder-abutment joint can be affected by the casting process, and that the choice of cylinder type, casting alloy, investment, and finishing/polishing technique may affect the resultant preload as compared to as-received joint conditions. The data from this study indicate that when plastic patterns are used as part of the framework, finishing and polishing of implant cylinder components should provide an increased preload compared to no such manipulations. Also, if maximum preload is desired, the use of premade metal cylinders offers an advantage over plastic patterns in both preload magnitude and precision.
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Affiliation(s)
- A B Carr
- Ohio State University, College of Dentistry, Columbus, USA
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Brunski JB. Chemical Compositions of Metals Used for Implants. Biomater Sci 1996. [DOI: 10.1016/b978-012582460-6/50017-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abramson S, Alexander H, Best S, Bokros J, Brunski JB, Colas A, Cooper SL, Curtis J, Haubold A, Hench LL, Hergenrother RW, Hoffman AS, Hubbell JA, Jansen JA, King MW, Kohn J, Lamba NM, Langer R, Migliaresi C, More RB, Peppas NA, Ratner BD, Visser SA, Recum AV, Weinberg S, Yannas IV. Classes of Materials Used in Medicine. Biomater Sci 1996. [DOI: 10.1016/b978-012582460-6/50005-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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