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Yuan X, Liu B, Cuevas P, Brunski J, Aellos F, Petersen J, Koehne T, Bröer S, Grüber R, LeBlanc A, Zhang X, Xu Q, Helms J. Linking the Mechanics of Chewing to Biology of the Junctional Epithelium. J Dent Res 2023; 102:1252-1260. [PMID: 37555395 PMCID: PMC10626588 DOI: 10.1177/00220345231185288] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023] Open
Abstract
The capacity of a tissue to continuously alter its phenotype lies at the heart of how an animal is able to quickly adapt to changes in environmental stimuli. Within tissues, differentiated cells are rigid and play a limited role in adapting to new environments; however, differentiated cells are replenished by stem cells that are defined by their phenotypic plasticity. Here we demonstrate that a Wnt-responsive stem cell niche in the junctional epithelium is responsible for the capability of this tissue to quickly adapt to changes in the physical consistency of a diet. Mechanical input from chewing is required to both establish and maintain this niche. Since the junctional epithelium directly attaches to the tooth surface via hemidesmosomes, a soft diet requires minimal mastication, and consequently, lower distortional strains are produced in the tissue. This reduced strain state is accompanied by reduced mitotic activity in both stem cells and their progeny, leading to tissue atrophy. The atrophied junctional epithelium exhibits suboptimal barrier functions, allowing the ingression of bacteria into the underlying connective tissues, which in turn trigger inflammation and mild alveolar bone loss. These data link the mechanics of chewing to the biology of tooth-supporting tissues, revealing how a stem cell niche is responsible for the remarkable adaptability of the junctional epithelium to different diets.
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Affiliation(s)
- X. Yuan
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- Department of Otolaryngology-Head & Neck Surgery, School of Medicine, Indiana University, Indianapolis, IN, USA
| | - B. Liu
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - P. Cuevas
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J. Brunski
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - F. Aellos
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J. Petersen
- Department of Orthodontics, University of Leipzig Medical Center, Saxony, Germany
| | - T. Koehne
- Department of Orthodontics, University of Leipzig Medical Center, Saxony, Germany
| | - S. Bröer
- Institute of Pharmacology and Toxicology, School of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - R. Grüber
- Department of Oral Biology, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
| | - A. LeBlanc
- Centre for Oral, Clinical & Translational Sciences, Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London, London, UK
| | - X. Zhang
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Q. Xu
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- The Affiliated Hospital of Qingdao University, College of Stomatology, Qingdao University, Qingdao, China
| | - J.A. Helms
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
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Chen J, Cuevas P, Dworan J, Dawid I, Turkkahraman H, Tran K, Delgado-Calle J, Bellido T, Gorski J, Liu B, Brunski J, Helms J. Wnt/β-catenin Signaling Controls Maxillofacial Hyperostosis. J Dent Res 2022; 101:793-801. [PMID: 35114849 PMCID: PMC10850863 DOI: 10.1177/00220345211067705] [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] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The roles of Wnt/β-catenin signaling in regulating the morphology and microstructure of craniomaxillofacial (CMF) bones was explored using mice carrying a constitutively active form of β-catenin in activating Dmp1-expressing cells (e.g., daβcatOt mice). By postnatal day 24, daβcatOt mice exhibited midfacial truncations coupled with maxillary and mandibular hyperostosis that progressively worsened with age. Mechanistic insights into the basis for the hyperostotic facial phenotype were gained through molecular and cellular analyses, which revealed that constitutively activated β-catenin in Dmp1-expressing cells resulted in an increase in osteoblast number and an increased rate of mineral apposition. An increase in osteoblasts was accompanied by an increase in osteocytes, but they failed to mature. The resulting CMF bone matrix also had an abundance of osteoid, and in locations where compact lamellar bone typically forms, it was replaced by porous, woven bone. The hyperostotic facial phenotype was progressive. These findings identify for the first time a ligand-independent positive feedback loop whereby unrestrained Wnt/β-catenin signaling results in a CMF phenotype of progressive hyperostosis combined with architecturally abnormal, poorly mineralized matrix that is reminiscent of craniotubular disorders in humans.
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Affiliation(s)
- J. Chen
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - P.L. Cuevas
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - J.S. Dworan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
- Medical University of Vienna, Department of Anatomy, Center for Anatomy and Cell Biology, Vienna, Austria
| | - I. Dawid
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - H. Turkkahraman
- Indiana University School of Dentistry, Department of Orthodontics & Oral Facial Genetics, Indianapolis, IN, USA
| | - K. Tran
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - J. Delgado-Calle
- Department of Physiology & Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - T. Bellido
- Department of Physiology & Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - J.P. Gorski
- Department of Oral and Craniofacial Sciences, School of Dentistry, and Center of Excellence in Mineralized Tissue Research, University of Missouri–Kansas City, Kansas City, MO, USA
| | - B. Liu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - J.B. Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - J.A. Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
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Zhang X, Yuan X, Xu Q, Arioka M, Van Brunt LA, Shi Y, Brunski J, Helms JA. Molecular Basis for Periodontal Ligament Adaptation to In Vivo Loading. J Dent Res 2019; 98:331-338. [PMID: 30612508 DOI: 10.1177/0022034518817305] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A soft food diet leads to changes in the periodontal ligament (PDL). These changes, which have been recognized for more than a century, are ascribed to alterations in mechanical loading. While these adaptive responses have been well characterized, the molecular, cellular, and mechanical mechanisms underlying the changes have not. Here, we implicate Wnt signaling in the pathoetiology of PDL responses to underloading. We show that Wnt-responsive cells and their progeny in the PDL space exhibit a burst in proliferation in response to mastication. If an animal is fed a soft diet from the time of weaning, then this burst in Wnt-responsive cell proliferation is quelled; as a consequence, both the PDL and the surrounding alveolar bone undergo atrophy. Returning these animals to a hard food diet restores the Wnt signaling in PDL. These data provide, for the first time, a molecular mechanism underlying the adaptive response of the PDL to loading.
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Affiliation(s)
- X Zhang
- 1 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 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
| | - Q Xu
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA.,3 The Affiliated Hospital of Qingdao University, College of Stomatology, Qingdao University, Qingdao, China
| | - M Arioka
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA.,4 Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - L A Van Brunt
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Y Shi
- 5 Los Altos High School, Los Altos, CA, USA
| | - J 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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Chen CH, Pei X, Tulu U, Aghvami M, Chen CT, Gaudillière D, Arioka M, Maghazeh Moghim M, Bahat O, Kolinski M, Crosby T, Felderhoff A, Brunski J, Helms J. A Comparative Assessment of Implant Site Viability in Humans and Rats. J Dent Res 2018; 97:451-459. [PMID: 29202640 PMCID: PMC5863872 DOI: 10.1177/0022034517742631] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Our long-term objective is to devise methods to improve osteotomy site preparation and, in doing so, facilitate implant osseointegration. As a first step in this process, we developed a standardized oral osteotomy model in ovariectomized rats. There were 2 unique features to this model: first, the rats exhibited an osteopenic phenotype, reminiscent of the bone health that has been reported for the average dental implant patient population. Second, osteotomies were produced in healed tooth extraction sites and therefore represented the placement of most implants in patients. Commercially available drills were then used to produce osteotomies in a patient cohort and in the rat model. Molecular, cellular, and histologic analyses demonstrated a close alignment between the responses of human and rodent alveolar bone to osteotomy site preparation. Most notably in both patients and rats, all drilling tools created a zone of dead and dying osteocytes around the osteotomy. In rat tissues, which could be collected at multiple time points after osteotomy, the fate of the dead alveolar bone was followed. Over the course of a week, osteoclast activity was responsible for resorbing the necrotic bone, which in turn stimulated the deposition of a new bone matrix by osteoblasts. Collectively, these analyses support the use of an ovariectomy surgery rat model to gain insights into the response of human bone to osteotomy site preparation. The data also suggest that reducing the zone of osteocyte death will improve osteotomy site viability, leading to faster new bone formation around implants.
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Affiliation(s)
- C.-H. Chen
- Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan, Taiwan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - X. Pei
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - U.S. Tulu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - M. Aghvami
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - C.-T. Chen
- Craniofacial Research Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University School of Medicine, Taoyuan, Taiwan
- Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital at Keelung, Keelung, Taiwan
| | - D. Gaudillière
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - M. Arioka
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - M. Maghazeh Moghim
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- University College London Medical School, University College London, London, UK
| | - O. Bahat
- Private practice, Beverly Hills, CA, USA
| | | | | | | | - J.B. Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J.A. Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
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Huang L, Liu B, Cha J, Yuan G, Kelly M, Singh G, Hyman S, Brunski J, Li J, Helms J. Mechanoresponsive Properties of the Periodontal Ligament. J Dent Res 2016; 95:467-75. [PMID: 26767771 DOI: 10.1177/0022034515626102] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The periodontal ligament (PDL) functions as an enthesis, a connective tissue attachment that dissipates strains created by mechanical loading. Entheses are mechanoresponsive structures that rapidly adapt to changes in their mechanical loading; here we asked which features of the PDL are sensitive to such in vivo loading. We evaluated the PDL in 4 physiologically relevant mechanical environments, focusing on mitotic activity, cell density, collagen content, osteogenic protein expression, and organization of the tissue. In addition to examining PDLs that supported teeth under masticatory loading and eruptive forces, 2 additional mechanical conditions were created and analyzed: hypoloading and experimental tooth movement. Collectively, these data revealed that the adult PDL is a remarkably quiescent tissue and that only when it is subjected to increased loads—such as those associated with mastication, eruption, and orthodontic tooth movement—does the tissue increase its rate of cell proliferation and collagen production. These data have relevance in clinical scenarios where PDL acclimatization can be exploited to optimize tooth movement.
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Affiliation(s)
- L. Huang
- Orthodontic Department, Stomatology Hospital of Chongqing Medical University; Chongqing Key Laboratory of Oral Disease and Biomedical Sciences; Chongqing Municipal Key Laboratory, Chongqing, China
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - B. Liu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - J.Y. Cha
- Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, South Korea
| | - G. Yuan
- Department of Orthodontics, Dalian Stomatological Hospital, Dalian Medical University, Dalian, China
| | - M. Kelly
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - G. Singh
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
| | - S. Hyman
- 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. Li
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
- Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - J.A. Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA, USA
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Tevlin R, Ardle AM, Senarath-Yapa K, Zielins E, Atashroo D, Hu M, Chan C, Walmsley G, Yang J, Brunski J, Dauskardt R, Longaker M. Mechanical Properties of Fracture Callus in Diabetes using a Bicortical Femoral Fracture Model. J Surg Res 2014. [DOI: 10.1016/j.jss.2013.11.337] [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: 10/25/2022]
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Mouraret S, Hunter D, Bardet C, Brunski J, Bouchard P, Helms J. A pre-clinical murine model of oral implant osseointegration. Bone 2014; 58:177-84. [PMID: 23886841 PMCID: PMC4962868 DOI: 10.1016/j.bone.2013.07.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [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: 11/23/2012] [Revised: 05/31/2013] [Accepted: 07/10/2013] [Indexed: 10/26/2022]
Abstract
Many of our assumptions concerning oral implant osseointegration are extrapolated from experimental models studying skeletal tissue repair in long bones. This disconnect between clinical practice and experimental research hampers our understanding of bone formation around oral implants and how this process can be improved. We postulated that oral implant osseointegration would be fundamentally equivalent to implant osseointegration elsewhere in the body. Mice underwent implant placement in the edentulous ridge anterior to the first molar and peri-implant tissues were evaluated at various timepoints after surgery. Our hypothesis was disproven; oral implant osseointegration is substantially different from osseointegration in long bones. For example, in the maxilla peri-implant pre-osteoblasts are derived from cranial neural crest whereas in the tibia peri-implant osteoblasts are derived from mesoderm. In the maxilla, new osteoid arises from periostea of the maxillary bone but in the tibia the new osteoid arises from the marrow space. Cellular and molecular analyses indicate that osteoblast activity and mineralization proceeds from the surfaces of the native bone and osteoclastic activity is responsible for extensive remodeling of the new peri-implant bone. In addition to histologic features of implant osseointegration, molecular and cellular assays conducted in a murine model provide new insights into the sequelae of implant placement and the process by which bone is generated around implants.
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Affiliation(s)
- S. Mouraret
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
- Department of Periodontology, Service of Odontology, Rothschild Hospital, AP-HP, Paris 7 Denis, Diderot University, U.F.R. of Odontology, Paris, France
| | - D.J. Hunter
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
| | - C. Bardet
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
- Dental School University Paris Descartes PRES Sorbonne Paris Cité, EA 2496 Montrouge, France
| | - J.B. Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
| | - P. Bouchard
- Department of Periodontology, Service of Odontology, Rothschild Hospital, AP-HP, Paris 7 Denis, Diderot University, U.F.R. of Odontology, Paris, France
| | - J.A. Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford School of Medicine, Stanford, CA 94305, USA
- Corresponding author. Fax: +1 650 736 4374. (J.A. Helms)
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Brunski J, Currey J, Helms J, Leucht P, Nanci A, Nicolella D, Wazen R. Mechanobiology at healing bone-implant interfaces: strain distribution and tissue response. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)83725-5] [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: 10/24/2022]
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Rangert B, Sennerby L, Meredith N, Brunski J. Design, maintenance and biomechanical considerations in implant placement. Dent Update 1997; 24:416-20. [PMID: 9534417] [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] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Successful treatment using implants involves careful consideration of fixture placement and prosthesis design if the biomechanical conditions are to be optimized. These parameters may be related to the implant/tissue interface at the individual fixture level, and thence to the relationship between the components of a prosthesis. The influence of the nature and magnitude of occlusal forces can also be significant and should be carefully assessed before placement.
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Affiliation(s)
- B Rangert
- Department of Biomaterials/Handicap Research Institute for Surgical Sciences, Göteborg University, Medicinaregatan, Gothenburg, Sweden
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Hipp J, Brunski J, Shephard M, Cochran G. Finite element modeling of implants in bone: Interfacial assumptions. J Biomech 1985. [DOI: 10.1016/0021-9290(85)90831-0] [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: 11/26/2022]
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Brunski J. DEVELOPMENT OF A BITE FORCE TRANSDUCER FOR USE WITH ENDOSSEOUS DENTAL IMPLANTS. Bioengineering (Basel) 1981. [DOI: 10.1016/b978-0-08-027207-8.50013-8] [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: 11/16/2022] Open
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