Current bone substitutes for implant dentistry

Zinc- and Fluoride-Releasing Bioactive Glass as a Novel Bone Substitute

Bioglass 45S5, a silica-based glass, has pioneered a new field of biomaterials. Bioglass 45S5 promotes mineralization through calcium ion release and is widely used in the dental field, including toothpaste formulations. However, the use of Bioglass 45S5 for bone grafting is limited owing to the induction of inflammation, as well as reduced degradation and ion release. Phosphate-based glasses exhibit higher solubility and ion release than silica-based glass. Given that these glasses can be synthesized at low temperatures (approximately 1,000°C), they can easily be doped with various metal oxides to confer therapeutic properties. Herein, we fabricated zinc- and fluoride-doped phosphate-based glass (multicomponent phosphate [MP] bioactive glass) and further doped aluminum oxide into the MP glass (4% Al-MP glass) to overcome the striking solubility of phosphate-based glass. Increased amounts of zinc and fluoride ions were detected in water containing the MP glass. Doping of aluminum oxide into the MP glass suppressed the striking dissolution in water, with 4% Al-MP glass exhibiting the highest stability in water. Compared with Bioglass 45S5, 4% Al-MP glass in water had a notably reduced particle size, supporting the abundant ion release of 4% Al-MP glass. Compared with Bioglass 45S5, 4% Al-MP glass enhanced the osteogenesis of mouse bone marrow-derived mesenchymal stem cells. Mouse macrophages cultured with 4% Al-MP glass displayed enhanced induction of anti-inflammatory M2 macrophages and reduced proinflammatory M1 macrophages, indicating M2 polarization. Upon implanting 4% Al-MP glass or Bioglass 45S5 in a mouse calvarial defect, 4% Al-MP glass promoted significant bone regeneration when compared with Bioglass 45S5. Hence, we successfully fabricated zinc- and fluoride-releasing bioactive glasses with improved osteogenic and anti-inflammatory properties, which could serve as a promising biomaterial for bone regeneration.

Comparative analysis of the in vivo kinetic properties of various bone substitutes filled into a peri-implant canine defect model

PURPOSE

Deproteinized bovine bone or synthetic hydroxyapatite are 2 prevalent bone grafting materials used in the clinical treatment of peri-implant bone defects. However, the differences in bone formation among these materials remain unclear. This study evaluated osteogenesis kinetics in peri-implant defects using 2 types of deproteinized bovine bone (Bio-Oss® and Bio-Oss/Collagen®) and 2 types of synthetic hydroxyapatite (Apaceram-AX® and Refit®). We considered factors including newly generated bone volume; bone, osteoid, and material occupancy; and bone-to-implant contact.

METHODS

A beagle model with a mandibular defect was created by extracting the bilateral mandibular third and fourth premolars. Simultaneously, an implant was inserted into the defect, and the space between the implant and the surrounding bone walls was filled with Bio-Oss, Bio-Oss/Collagen, Apaceram-AX, Refit, or autologous bone. Micro-computed tomography and histological analyses were conducted at 3 and 6 months postoperatively (Refit and autologous bone were not included at the 6-month time point due to their rapid absorption).

RESULTS

All materials demonstrated excellent biocompatibility and osteoconductivity. At 3 months, Bio-Oss and Apaceram-AX exhibited significantly greater volumes of formation than the other materials, with Bio-Oss having a marginally higher amount. However, this outcome was reversed at 6 months, with no significant difference between the 2 materials at either time point. Apaceram-AX displayed notably slower bioresorption and the largest quantity of residual material at both time points. In contrast, Refit had significantly greater bioresorption, with complete resorption and rapid maturation involving cortical bone formation at the crest at 3 months, Refit demonstrated the highest mineralized tissue and osteoid occupancy after 3 months, albeit without statistical significance.

CONCLUSIONS

Overall, the materials demonstrated varying post-implantation behaviors in vivo. Thus, in a clinical setting, both the properties of these materials and the specific conditions of the defects needing reinforcement should be considered to identify the most suitable material.

Immediately placed implants using simvastatin and autogenous tooth graft combination in periodontally compromised sites: a randomized controlled clinical trial

OBJECTIVES

The present study aimed to assess clinically and radiographically the usage of autogenous tooth bone graft (ATBG) combined with and without Simvastatin (SMV) around immediately placed dental implants in periodontally compromised sites.

METHODS

Thirty-nine patients required a single extraction of periodontally compromised tooth were divided into three groups (13 patients each). Group I received immediate implant placement (IIP) without grafting. Group II received IIP with ATBG filling the gap around IIP. Group III received SMV gel mixed with ATBG around IIP. Radiographic changes were reported at the baseline, 6-, and 12-months post-surgery.

RESULTS

All implants achieved the success criteria with no complications. At 6- and 12-months post-surgery, group III showed a statistically lower mean ridge width loss compared to Group I and Group II (P < .001). Group II revealed less reduction in the mean alveolar ridge width compared to group I (P < .001). Group III showed a statistically significantly less MBL loss than group I and group II (P < .001). All groups showed a statistically significant increase in BD gain compared to baseline (P < .001). Group III showed statistically significant high BD compared to group II (P < .001). Group II showed statistically significantly higher mean BD gain than that of group I (P < .001).

CONCLUSION

SMV combined with ATBG boosts the hard tissue parameters around dental implants over ATBG alone. Clinical trial registration was on August 1, 2021 (NCT04992416).

CLINICAL RELEVANCE

ATBG with SMV in periodontally compromised sites could improve implant osseointegration and promote favorable changes in peri-implant tissues.

Biomaterial scaffolds in maxillofacial bone tissue engineering: A review of recent advances

Maxillofacial bone defects caused by congenital malformations, trauma, tumors, and inflammation can severely affect functions and aesthetics of maxillofacial region. Despite certain successful clinical applications of biomaterial scaffolds, ideal bone regeneration remains a challenge in maxillofacial region due to its irregular shape, complex structure, and unique biological functions. Scaffolds that address multiple needs of maxillofacial bone regeneration are under development to optimize bone regeneration capacity, costs, operational convenience. etc. In this review, we first highlight the special considerations of bone regeneration in maxillofacial region and provide an overview of the biomaterial scaffolds for maxillofacial bone regeneration under clinical examination and their efficacy, which provide basis and directions for future scaffold design. Latest advances of these scaffolds are then discussed, as well as future perspectives and challenges. Deepening our understanding of these scaffolds will help foster better innovations to improve the outcome of maxillofacial bone tissue engineering.

Peri-implant epidermoid cyst: A case report and literature analysis

BACKGROUND

A peri-implant cystic lesion is a rare finding, and to date most investigators have considered that its pathogenesis is caused by trauma and infection related to dental implantation. However, the pathogenesis of these cysts remains unclear and is recognized to have multifactorial origins.

CASE PRESENTATION

In February 2021, a 75-year-old male patient underwent implant restoration due to mobility of the left maxillary central incisor. The implant achieved good osseointegration and was successfully restored. However, in March 2023, the patient sought treatment due to mobility of the dental implant. Clinical examination showed that the implant had loosened in three directions (vertical, mesial-distal, and labial-lingual), and the peri-implant mucosa was slightly red and swollen. Radiographic examination (cone beam computed tomography) showed a large radiolucent area with clear boundaries involving the cervical and middle portions of the dental implant, and white bone lines were observed at the edge of the low-density shadow. Intraoperatively, we removed the patient's implant, performed a complete debridement, and conducted bone augmentation surgery in the area of bone defect. Postoperatively, the patient recovered well. The final histopathological result confirmed an epidermoid cyst.

CONCLUSIONS

Peri-implant epidermoid cyst is a rare complication that affects the long-term outcome of implant therapy. This case serves as a warning to clinicians to avoid involving epithelial tissue in the implant site during implant surgery, in order to prevent the potential occurrence of a peri-implant epidermoid cyst, thereby creating better conditions for the patient's recovery and the long-term efficacy of the implant.

Peri-Implant Mucosal Fenestration and Histologic Observation of Bone Xenograft Material 7-Years After Implant Installation: A Case Report

Bone augmentation is often required before the installation of dental implants. Here, we report a case for a patient who previously received bone augmentation at the upper right jaw using a xenogenic graft, followed by successful implant installation. Seven years later, the patient presented with mucosal fenestration with bone exposure at the area and gave a history of a recent diagnosis of cutaneous lichen planus. Several attempts were made to manage the situation, and finally, we resorted to connective tissue graft placement at the site. A piece of bone was sent for histologic evaluation, where the results indicated the presence of un-resorbed graft material surrounded by inflammatory cells, with no evidence of bone formation in the area. The case presents histologic evidence for the lack of new bone formation using xenograft over the evaluation period. The case also shows lichen planus, a possible cause for oral complication for patients undergoing augmentation and implant installation.

Comparison of the Volume and Histological Properties of Newly Formed Bone after the Application of Three Types of Bone Substitutes in Critical-Sized Bone Defects

This study aimed to compare the volume and quality of the newly formed bone following application of two types of xenografts and one synthetic material in bone defects in rabbit calvaria from histological and micro-CT aspects. Four 8-mm defects were created in 12 rabbit calvaria. Three defects were filled with bone substitutes and one was left unfilled as the control group. The newly formed bone was evaluated histologically and also by micro-CT at 8 and 12 weeks after the intervention. The percentage of osteogenesis was comparable in histomor-phometric assessment and micro-CT. Histological analysis showed that the percentage of the newly formed bone was 10.92 ± 5.17%, 14.70 ± 11.02%, 11.47 ± 7.04%, and 9.45 ± 5.18% in groups bovine 1, bovine 2, synthetic, and negative control, respectively after 8 weeks. These values were 33.70 ± 11.48%, 26.30 ± 18.05%, 22.92 ± 6.30%, and 14.82 ± 8.59%, respectively at 12 weeks. The difference in the percentage of the new bone formation at 8 and 12 weeks was not significant in any group (P > 0.05) except for bovine 1 group (P < 0.05). Micro-CT confirmed new bone formation in all groups but according to the micro-CT results, the difference between the control and other groups was significant in this respect (P < 0.05). All bone substitutes enhanced new bone formation compared with the control group. Micro-CT assessment yielded more accurate and different results compared with histological assessment.

Bone regeneration in critical-size defects of the mandible using biomechanically adapted CAD/CAM hybrid scaffolds: An in vivo study in miniature pigs

The study aimed to analyze bone regeneration in critical-size defects using hybrid scaffolds biomechanically adapted to the specific defect and adding the growth factor rhBMP-2. For this animal study, ten minipigs underwent bilateral defects in the corpus mandibulae and were subsequently treated with novel cylindrical hybrid scaffolds. These scaffolds were designed digitally to suit the biomechanical requirements of the mandibular defect, utilizing finite element analysis. The scaffolds comprised zirconium dioxide-tricalcium phosphate (ZrO2-TCP) support struts and TCP foam ceramics. One scaffold in each animal was loaded with rhBMP-2 (100 μg/cm³), while the other served as an unloaded negative control. Fluorescent dyes were administered every 2 weeks, and computed tomography (CT) scans were conducted every 4 weeks. Euthanasia was performed after 3 months, and samples were collected for examination using micro-CT and histological evaluation of both hard and soft tissue. Intravital CT examinations revealed minor changes in radiographic density from 4 to 12 weeks postoperatively. In the group treated with rhBMP-2, radiographic density shifted from 2513 ± 128 (mean ± SD) to 2606 ± 115 Hounsfield units (HU), while the group without rhBMP-2 showed a change from 2430 ± 131 to 2601 ± 67 HU. Prior to implantation, the radiological density of samples measured 1508 ± 30 mg HA/cm³, whereas post-mortem densities were 1346 ± 71 mg HA/cm³ in the rhBMP-2 group and 1282 ± 91 mg HA/cm³ in the control group (p = 0.045), as indicated by micro-CT measurements. The histological assessment demonstrated successful ossification in all specimens. The newly formed bone area proportion was significantly greater in the rhBMP-2 group (48 ± 10%) compared with the control group without rhBMP-2 (42 ± 9%, p = 0.03). The mean area proportion of remaining TCP foam was 23 ± 8% with rhBMP-2 and 24 ± 10% without rhBMP-2. Successful bone regeneration was accomplished by implanting hybrid scaffolds into critical-size mandibular defects. Loading these scaffolds with rhBMP-2 led to enhanced bone regeneration and a uniform distribution of new bone formation within the hybrid scaffolds. Further studies are required to determine the adaptability of hybrid scaffolds for larger and potentially segmental defects in the maxillofacial region.

Application of CAD-CAM Technologies for Maxillofacial Bone Regeneration: A Narrative Review of the Clinical Studies

The application of regenerative methods in treating maxillofacial defects can be categorized as functional bone regeneration in which scaffolds without protection are used and in-situ bone regeneration in which a protected healing space is created to induce bone formation. It has been shown that functional bone regeneration can reduce surgical time and obviate the necessity of autogenous bone grafting. However, studies mainly focused on applying this method to reconstruct minor bone effects, and more investigation concerning the large defects is required. In terms of in situ maxillofacial bone regeneration with the help of CAD-CAM technologies, the present data have suggested feasible mesh rigidity, perseverance of the underlying space, and apt augmentative results with CAD-CAM-based individualized Ti meshes. However, complications, including dehiscence and mesh exposure, coupled with consequent graft loss, infection and impeded regenerative rates have also been reported.

Alveolar ridge preservation of damaged or periodontally compromised extraction sockets with bovine- and porcine-derived block bone substitutes: A retrospective case-control study

PURPOSE

Alveolar ridge preservation (ARP) was introduced to minimize postextraction alveolar bone loss and extraction socket remodeling; however, current knowledge of the ARP procedure for nonintact extraction sockets is still limited and inconclusive. This retrospective study aimed to evaluate the difference between using deproteinized bovine bone mineral with 10% collagen (DBBM-C) and deproteinized porcine bone mineral with 10% collagen (DPBM-C) when performing ARP procedures in damaged or periodontally compromised extraction sockets based on clinical, radiographic, and profilometric outcomes.

METHODS

In total, 108 extraction sockets were grafted with 67 DBBM-C and 41 DPBM-C. Changes in radiographic (horizontal width and vertical height) and profilometric outcomes were measured after the ARP procedure and before the implant surgery. Postoperative discomfort (including the severity and duration of pain and swelling), early wound healing outcomes (including spontaneous bleeding and persistent swelling), implant stability, and treatment modalities for implant placement were also assessed.

RESULTS

Radiographically, the DBBM-C group decreased by -1.70 ± 2.26 mm (-21.50%) and - 1.39 ± 1.85 mm (-30.47%) horizontally and vertically, and the corresponding DPBM-C group decreased by -1.66 ± 1.80 mm (-20.82%) and -1.44 ± 1.97 mm (-27.89%) horizontally and vertically at an average of 5.6 months. There were no serious or adverse complications in any of the cases, and none of the measured parameters differed significantly between the groups.

CONCLUSION

Within the limitations of this study, ARP with DBBM-C and DPBM-C showed similar clinical, radiographic, and profilometric outcomes in nonintact extraction sockets.

Maxillary sinus membrane elevation and coagulum compared with maxillary sinus floor augmentation and a composite graft: A 1-year single-blinded randomized controlled trial

OBJECTIVE

The aim was to evaluate the 1-year implant outcome and patient-related outcome measures (PROMs) after maxillary sinus membrane elevation and coagulum (test) compared with maxillary sinus floor augmentation and a 1:1 ratio of autogenous bone graft from the buccal antrostomy and deproteinised porcine bone mineral (DPBM) (control).

MATERIALS AND METHODS

Forty patients (30 female, 10 male) with a mean age of 50 years (range 25-71 years) and an alveolar ridge height between 4 and 7 mm were randomly allocated to test or control. Outcome measures included survival of suprastructures and implants, implant stability quotient, health status of the peri-implant tissue, peri-implant marginal bone loss, frequency of complications and PROMs using Oral Health Impact Profile-14 combined with questionnaires assessing patient's perception of the peri-implant soft tissue, implant crown, function of the implant, and total implant treatment outcome using visual analogue scale. Mean differences were expressed with standard deviation and 95% confidence interval. Level of significance was 0.05.

RESULTS

All suprastructures and implants were well-functioning after 1-year of functional implant loading. No significant difference in any of the applied outcome measures was observed between test and control. Both treatments revealed high patient satisfaction scores and significant improvement in oral health-related quality of life.

CONCLUSION

There were no significant differences in implant outcome and PROMs between test and control, after 1-year of functional implant loading. Neither of the treatments can therefore be considered better than the other. Thus, long-term randomized controlled trials are needed before definitive conclusions can be provided about the two treatment modalities.

Bone regeneration in implant dentistry: Which are the factors affecting the clinical outcome?

The key factors that are needed for bone regeneration to take place include cells (osteoprogenitor and immune-inflammatory cells), a scaffold (blood clot) that facilitates the deposition of the bone matrix, signaling molecules, blood supply, and mechanical stability. However, even when these principles are met, the overall amount of regenerated bone, its stability over time and the incidence of complications may significantly vary. This manuscript provides a critical review on the main local and systemic factors that may have an impact on bone regeneration, trying to focus, whenever possible, on bone regeneration simultaneous to implant placement to treat bone dehiscence/fenestration defects or for bone contouring. In the future, it is likely that bone tissue engineering will change our approach to bone regeneration in implant dentistry by replacing the current biomaterials with osteoinductive scaffolds combined with cells and mechanical/soluble factors and by employing immunomodulatory materials that can both modulate the immune response and control other bone regeneration processes such as osteogenesis, osteoclastogenesis, or inflammation. However, there are currently important knowledge gaps on the biology of osseous formation and on the factors that can influence it that require further investigation. It is recommended that future studies should combine traditional clinical and radiographic assessments with non-invasive imaging and with patient-reported outcome measures. We also envisage that the integration of multi-omics approaches will help uncover the mechanisms responsible for the variability in regenerative outcomes observed in clinical practice.

First Clinical Case Report of a Xenograft-Allograft Combination for Alveolar Ridge Augmentation Using a Bovine Bone Substitute Material with Hyaluronate (Cerabone® Plus) Combined with Allogeneic Bone Granules (Maxgraft®)

BACKGROUND

A patient had lost the first left maxillary incisor in the esthetic zone.

METHODS

The defect in the alveolar ridge was reconstructed for an implant-supported restoration using a new xenogeneic bone substitute containing hyaluronate, which was used in combination with allogeneic bone granules.

RESULTS

After three years of follow-up, the dental implant was stable and showed no signs of infection.

CONCLUSIONS

This is the first case report with a long-term follow-up time of three years of a successful clinical application of a xenograft-allograft combination (cerabone® plus combined with maxgraft®) for alveolar ridge augmentation before dental implantation. Cerabone® plus offers volume stability, provides reliable and efficient structural support of the oral soft tissues in the augmented region (particularly crucial in the aesthetic zone), and preserves the alveolar ridge shape.

Optimized osteogenesis of porcine bone-derived xenograft through surface coating of magnesium-doped nanohydroxyapatite

As one of the key factors influencing the outcome of guided bone regeneration, the currently used xenografts possess insufficient capability in osteogenesis. With the aim of improving the osteogenic performance of xenografts, porcine bone-derived hydroxyapatite (PHA) was prepared and subsequently coated by magnesium-doped nano hydroxyapatite (nMgHA, 10%, 20%, and 30% of Mg/Ca + Mg) through a straightforward and cost-efficient approach. The physiochemical and biological properties of nMgHA/PHAs were examinedin vitroandin vivo. The inherent three-dimensional (3D) porous framework with the average pore size of 300 μm was well preserved in nMgHA/PHAs. Meanwhile, excess magnesium released from the so-called 'surface pool' of PHA was verified. In contrast, slower release of magnesium at lower concentrations was detected for nMgHA/PHAs. Significantly more newly-formed bone and microvessels were observed in 20%nMgHA/PHA than the other specimens. With the limitations of the present study, it could be concluded that PHA coated by 20%nMgHA may have the optimized osteogenic performance due to the elimination of the excess magnesium from the 'surface pool', the preservation of the inherent 3D porous framework with the favorable pore size, and the release of magnesium at an appropriate concentration that possessed osteoimmunomodulatory effects on macrophages.

The healing capacity and osteogenesis pattern of demineralized dentin matrix (DDM)-fibrin glue (FG) compound

Demineralized dentin matrix (DDM) is an osteoconductive and osteoinductive material that has been successfully used in sinus floor augmentation and alveolar ridge augmentation in clinical applications. It releases bone morphogenetic proteins (BMPs) and other growth factors, making DDM a suitable grafting material. However, the granular particle of DDM makes it difficult to anchor into the bone defect area. The aim of this study was to investigate the biological effects and osteoinductivity of the combination of DDM and Fibrin Glue (FG) at an optimal ratio on bone healing from a critical bone defect in an animal model. The mouse osteoblastic cell line (MC3T3-E1) was co-cultured with various ratios of DDM and FG to examine their effects on osteoblast proliferation and differentiation, as indicated by alkaline phosphatase (ALP) activity, osteocalcin (OC) production and mineralized nodules formation. The optimal ratio was then chosen for further study with a rabbit calvarial defective model, in which they were implanted with DDM or DDM-FG1 (1 g: 0.1 ml) and DDM-FG2 (1 g: 0.5 ml) compounds, or left blank for 2, 4, 8 and 12 weeks to investigate soft tissue and new bone regeneration. Micro-CT and histology analysis were used to evaluate the total grafting properties according to the different healing periods. The result from in vitro studies demonstrated that the ratio of 1:0.1 induced more ALP activity and mineralized nodules, while the ratio of 1: 0.5 (DDM-FG combined) induced more osteocalcin (OC) at specific time points. In the animal model, the 3D new bone volume in all DDM-FG treatment groups was significantly greater than that in the blank group at 2, 4, 8 and 12 weeks. Furthermore, the new bone volume was greater in DDM-FG2 when compared to the other groups during the early weeks of the healing period. In histological analysis, clusters of osteoblasts were formed adjacent to the DDM particles, and newly formed bone was observed in all groups, suggesting an osteoinductive property of DDM. Moreover, the greater new collagen synthesis observed at 4 weeks suggested that early bone healing was induced in the DDM-FG2 group. This study demonstrated that at an optimal ratio, the DDM-FG compound enhances osteogenic activities and bone regeneration.

Evaluation of the clinical and radiographic effectiveness of treating peri-implant bone defects with a new biphasic calcium phosphate bone graft: a prospective, multicenter randomized controlled trial

PURPOSE

Biphasic calcium phosphate (BCP), a widely used biomaterial for bone regeneration, contains synthetic hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), the ratio of which can be adjusted to modulate the rate of degradation. The aim of this study was to evaluate the clinical and radiographic benefits of reconstructing peri-implant bone defects with a newly developed BCP consisting of 40% β-TCP and 60% HA compared to demineralized bovine bone mineral (DBBM).

METHODS

This prospective, multicenter, parallel, single-blind randomized controlled trial was conducted at the periodontology departments of 3 different dental hospitals. Changes in clinical (defect width and height) and radiographic (augmented horizontal bone thickness) parameters were measured between implant surgery with guided bone regeneration (GBR) and re-entry surgery. Postoperative discomfort (severity and duration of pain and swelling) and early soft-tissue wound healing (dehiscence and inflammation) were also assessed. Data were compared between the BCP (test) and DBBM (control) groups using the independent t-test and the χ² test.

RESULTS

Of the 53 cases included, 27 were in the test group and 26 were in the control group. After a healing period of 18 weeks, the full and mean resolution of buccal dehiscence defects were 59.3% (n=16) and 71.3% in the test group and 42.3% (n=11) and 57.9% in the control group, respectively. There were no significant differences between the groups in terms of the change in mean horizontal bone augmentation (test group: -0.50±0.66 mm vs. control groups: -0.66±0.83 mm, P=0.133), postoperative discomfort, or early wound healing. No adverse or fatal complications occurred in either group.

CONCLUSION

The GBR procedure with the newly developed BCP showed favorable clinical, radiographic, postoperative discomfort-related, and early wound healing outcomes for peri-implant dehiscence defects that were similar to those for DBBM.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0006428.

Efficacy of pure beta tricalcium phosphate graft in dentoalveolar surgery: a retrospective evaluation based on serial radiographic images

BACKGROUND

The use of beta-tricalcium phosphate (beta-TCP) in dental surgery is limited owing to its rapid absorption compared to mixed formulations of hydroxyapatite. However, newly developed pure beta-TCP crystals have demonstrated slow absorption; hence, they last longer within the defect and act as a scaffold until new bone formation. The oral environment is unique and can prove unfavorable for bone grafts due to the high infection rate in the oral cavity and the fragile condition of the oral mucosa. The aim of this study was to evaluate the feasibility of using pure beta-TCP bone grafts in various dental treatments.

METHODS

Panoramic X-ray images of 25 patients who underwent bone grafting during dental surgery were analyzed. A specially treated pure beta-TCP crystal, Neo Bone® (Neo Bone®, SN Biologics Co., Ltd, Seoul, Korea), was used in this study. The bone density at the graft site was compared with that of the surrounding bone using the ImageJ software (Wayne Rasband, NIH USA).

RESULTS

Six months after surgery, the bone graft density was similar to that of the surrounding bone in 20 patients and increased in 5 patients. No adverse effects, such as infection, dehiscence, or graft failure, were observed.

CONCLUSION

The newly developed pure beta-TCP crystal was slowly absorbed and served as support until new bone formation at the defect site, thus demonstrating its potential for use in various oral conditions requiring bone grafting.

A novel porcine dentin-derived bone graft material provides effective site stability for implant placement after tooth extraction: a randomized controlled clinical trial

OBJECTIVES

Assessment of the clinical performance of a porcine dentin-derived particulate bone graft material for bone regeneration after tooth extraction with implant placement at 4 months, in comparison to a commercially available porcine bone-derived graft.

MATERIAL AND METHODS

This study was a randomized, parallel-group, semi-double-blinded clinical trial evaluating the clinical safety, tolerability, and performance of Ivory Dentin Graft™ in comparison with a commercial bone-derived material in alveolar ridge preservation following tooth extraction (registered at ClinicalTrials.gov, May 12th, 2017, Identifier NCT03150472). Extraction sites were grafted with test or comparator material and a titanium implant placed at 4 months after taking a graft site biopsy. Primary endpoints were the extent of new bone growth and bone-graft integration at 4 months.

RESULTS

The dentin graft material had statistically significantly more new bone formation (60.75% vs 42.81%, p = 0.0084, N = 20 vs 16), better bone-graft integration scores (good integration in 85% vs 40%, p = 0.0066), and higher mean radiodensity of the bone (981.5HU vs 727.7HU, p = 0.0011) at the graft site compared to the bone-derived material. The mean implant insertion torque force was similar for the dentin and bone materials (34.75 Ncm vs 34.06 Ncm). Titanium implant placement was successful in 95% of patients with the dentin graft material compared to 81.25% for the bone graft. Both materials had similar clinical safety and tolerability as determined by adverse events and local site reactions. Physician-assessed ease of grafting and ease of implant placement on a 10-point scale showed no statistical differences (8.78 vs 8.27, p = 0.2355; 8.05 vs 8.75, p = 0.1118, respectively).

CONCLUSIONS

A porcine dentin-derived bone graft material has clinical safety, tolerability, and performance for implant placement at 4 months after tooth extraction at least as good as a commercial bone-derived material.

CLINICAL RELEVANCE

The availability of porcine dentin-derived bone graft material allows wider use of dentin-derived material which has so far only been available in the form of autologous dentin from the patient's own teeth.

Piezoelectric Biocomposites for Bone Grafting in Dentistry

In this research, Hydroxyapatite-Potassium, Sodium Niobate-Chitosan (HA-KNN-CSL) biocomposites were synthesized, both as hydrogel and ultra-porous scaffolds, to offer two commonly used alternatives to biomaterials in dental clinical practice. The biocomposites were obtained by varying the content of low deacetylated chitosan as matrix phase, mesoporous hydroxyapatite nano-powder, and potassium-sodium niobate (K_0.47Na_0.53NbO₃) sub-micron-sized powder. The resulting materials were characterized from physical, morpho-structural, and in vitro biological points of view. The porous scaffolds were obtained by freeze-drying the composite hydrogels and had a specific surface area of 18.4-24 m²/g and a strong ability to retain fluid. Chitosan degradation was studied for 7 and 28 days of immersion in simulated body fluid without enzymatic presence. All synthesized compositions proved to be biocompatible in contact with osteoblast-like MG-63 cells and showed antibacterial effects. The best antibacterial effect was shown by the 10HA-90KNN-CSL hydrogel composition against Staphylococcus aureus and the fungal strain Candida albicans, while a weaker effect was observed for the dry scaffold.

Alveolar ridge augmentation with 3D-printed synthetic bone blocks: A clinical case series

This report documents the clinical and histological outcome of 3D-printed calcium phosphate blocks placed in two-stage procedures to successfully rehabilitate atrophic alveolar ridges. This approach yielded a functionally favorable result. Histological evaluations were performed after healing periods of 6 months and showed ongoing bone regeneration and sprouting capillaries.

Osteogenic Potential of Autologous Dentin Graft Compared with Bovine Xenograft Mixed with Autologous Bone in the Esthetic Zone: Radiographic, Histologic and Immunohistochemical Evaluation

This prospective, randomized, controlled clinical trial reports clinical, radiographic, histologic and immunohistochemical results of autologous dentin graft (ADG) and its comparison with a mixture of bovine xenograft with autologous bone (BX+AB). After tooth extraction in the esthetic zone of maxilla, the alveolar ridge of 20 patients in the test group was augmented with ADG, while 17 patients in the control group received the combination of BX+AB. Cone beam computed tomography (CBCT) was performed before tooth extraction and after 4 months when a total of 22 bone biopsies were harvested and subjected to histological and immunohistochemical analysis. Radiological analysis showed comparable results of bone dimension loss in both groups. Quantitative histologic analysis showed comparable results with no statistically significant differences between the groups. Immunohistochemical staining with TNF-α and BMP-4 antibodies revealed immunopositivity in both groups. A statistically significant difference between the groups was found in the intensity of TNF-α in the area of newly formed bone (p = 0.0003) and around remaining biomaterial particles (p = 0.0027), and in the intensity of BMP-4 in the area around biomaterial particles (p = 0.0001). Overall, ADG showed biocompatibility and achieved successful bone regeneration in the esthetic zone of the maxilla similar to BX+AB.

An overview of translational research in bone graft biomaterials

Natural bone healing is often inadequate to treat fractures with critical size bone defects and massive bone loss. Immediate surgical interventions through bone grafts have been found to be essential on such occasions. Naturally harvested bone grafts, although are the preferred choice of the surgeons; they suffer from serious clinical limitations, including disease transmission, donor site morbidity, limited supply of graft etc. Synthetic bone grafts, on the other hand, offer a more clinically appealing approach to decode the pathways of bone repair through use of tissue engineered biomaterials. This article critically retrospects the translational research on various engineered biomaterials towards bringing transformative changes in orthopaedic healthcare. The first section of the article discusses about composition and ultrastructure of bone along with the global perspectives on statistical escalation of bone fracture surgeries requiring use of bone grafts. The next section reviews the types, benefits and challenges of various natural and synthetic bone grafts. An overview of clinically relevant biomaterials from traditionally used metallic, bioceramic, and biopolymeric biomaterials to new generation composites have been summarised. Finally, this narrative review concludes with the discussion on the emerging trends and future perspectives of the promising bone grafts.

A Novel Construct of Coral Granules-Poly-L-Lactic Acid Nanomembrane Sandwich Double Stem Cell Sheet Transplantation as Regenerative Therapy of Bone Defect Model

OBJECTIVES

We examined the use of a new approach in nanotechnology and stem cell research as regenerative therapy for bone tissue defects.

MATERIALS AND METHODS

We compared in vitro osteogenic potential of human Wharton jelly mesenchymal stem cells using coral granules and poly-L-lactic acid nanofiber according to proliferation (by cck-8 kit) and osteogenes (runt-related transcription factor 2, alkaline phosphatase, osteonectin) by quantitative reverse transcription-polymerase chain reaction, alkaline phosphatase assay, calcium measurement, and assessment of mineralization by Alizarin red and von Kossa staining. To overcome the limitations of natural coral, we made a modification by packaging the coral granules-human Wharton jelly mesenchymal stem cells by nanomembrane-human Wharton jelly mesenchymal stem cells to form sandwich double cell sheets and compared this hole with other holes (one was filled by human Wharton jelly mesenchymal stem cell suspension, and the other was filled by coral granules saturated with preinduced mesenchymal stem cells) by radiological and histopathological studies for repairing the bone gap.

RESULTS

Collagen-coated poly-L-lactic acid showed higher mRNA levels for all osteogenes (P < .001), higher alkaline phosphatase and calcium content (P < .001), and greater stainability. Our in vivo experiment showed that the holes implanted with sandwich double cell sheet-poly-L-lactic acid coral were completely filled mature compact bone. The holes implanted with human Wharton jelly mesenchymal stem cells alone were filled with immature compact bone. Holes implanted with coral granules-human Wharton jelly mesenchymal stem cells were filled with condensed connective tissue.

CONCLUSIONS

Poly-L-lactic acid nanofiber has greater osteogenic differentiating effect than the coral granules. The new approach of sDCS-PLLA-coral construct proved success for bone regeneration and repairing the bone gap and this may improve the design of tissue constructs for bone tissue regenerative therapy.

Cellular Behaviors of Periodontal Ligament Stem Cells in the Presence of Bone Grafting Biomaterials, In-Vitro Study

Periodontal regeneration through the employment of bone substitutes has become a feasible strategy in animal and clinical studies. In this regard, we aimed to compare the periodontal ligament stem cell behavior in the vicinity of various bone grafting substitutes. Three types of popular bone substitutes, including allografts (Regen), xenografts (Cerabone), and alloplasts (Osteon) were studied in this experimental survey. The cellular attachment was assessed after four hours using the MTS assay and SEM imaging. In addition, cellular proliferation was investigated after 1, 3, 5, and 7 days through MTS assay. Osteogenesis was studied after 21 days of cell culture in a differentiation medium (DM+) and a normal medium (DM-), by employing real-time PCR and alizarin red staining. The highest cellular attachment was seen in the xenograft group with a significant difference in comparison to the other grafting materials. Despite the relatively low primary attachment of cells to allografts, the allograft group showed the highest total proliferation rate, while the lowest proliferation capacity was found in the alloplast group. Osteogenesis fount to be accelerated mostly by xenografts in both mediums (DM+ and DM-) after 3 weeks, while alloplasts showed the lowest osteogenesis. This study revealed that the type of bone substitutes used in regenerative treatments can affect cellular behavior and as a whole allografts and xenografts showed better results.

Assessment of tricalcium phosphate/titanium dioxide (TCP/TiO2) nanocomposite scaffold compared with bone autograft and hydroxyapatite (HA) on the healing of segmental femur bone defect in rabbits

Bone healing is a tissue process after a surgical operation. Many formulated materials have been designed for improving these procedures. The purpose of this study was to evaluate the effectiveness of nanocomposite tricalcium phosphate scaffolds combined with Titanium dioxide scaffold (TCP/TiO2) for femoral defects regeneration in rabbits. We studied 80 mature male New Zealand white rabbits weighing between 3 and 3.5 kg. Rabbits were subdivided into four groups. Anesthesia was performed before surgical operation by 50 mg/kg Ketamine 10% and 5 mg/kg xylazine 5% intramuscularly. We inducted a 6 × 5 mm diameter cylinder defect on the femur. Animals were separated into four trial groups of 20 animals each. After defecting, the experimental groups include control, autograft, hydroxyapatite, and TCP/TiO2 (received pure nanocomposite TCP/TiO2 material). A pathologist evaluated the sections on days 15, 30, 45, and 60 after surgery. The improvement of new and lamellar bone formation was the best in the nanocomposite TCP/TiO2 group at various point times, especially 60 days after surgery. We found that TCP/TiO2 nanocomposite has a significant improving function in the remodeling of bone in the defect areas. Graphical abstract.

Bone Formation on Murine Cranial Bone by Injectable Cross-Linked Hyaluronic Acid Containing Nano-Hydroxyapatite and Bone Morphogenetic Protein

New injection-type bone-forming materials are desired in dental implantology. In this study, we added nano-hydroxyapatite (nHAp) and bone morphogenetic protein (BMP) to cross-linkable thiol-modified hyaluronic acid (tHyA) and evaluated its usefulness as an osteoinductive injectable material using an animal model. The sol (ux-tHyA) was changed to a gel (x-tHyA) by mixing with a cross-linker. We prepared two sol−gel (SG) material series, that is, x-tHyA + BMP with and without nHAp (SG I) and x-tHyA + nHAp with and without BMP (SG II). SG I materials in the sol stage were injected into the cranial subcutaneous connective tissues of mice, followed by in vivo gelation, while SG II materials gelled in Teflon rings were surgically placed directly on the cranial bones of rats. The animals were sacrificed 8 weeks after implantation, followed by X-ray analysis and histological examination. The results revealed that bone formation occurred at a high rate (>70%), mainly as ectopic bone in the SG I tests in mouse cranial connective tissues, and largely as bone augmentation in rat cranial bones in the SG II experiments when x-tHyA contained both nHAp and BMP. The prepared x-tHyA + nHAp + BMP SG material can be used as an injection-type osteoinductive bone-forming material. Sub-periosteum injection was expected.

Use of a Lateral Sinus Bony Window as an Intraoral Donor Site for Guided Bone Regeneration in Wide Post-Extraction Defects

Maxillary sinus augmentation (MSA) and guided bone regeneration (GBR) have shown successful clinical, radiological, and histological outcomes for implant-related bone reconstruction and have been used to augment bony defects of various shapes and sizes. This study demonstrated that the lateral sinus bony window obtained during MSA can be used as an autogenous block bone graft for the augmentation of wide post-extraction defects. During the uncovering procedure performed 6 months after surgery, the grafted lateral bony window was well integrated with the adjacent native bone, and complete bone filling was observed in all bony defects around the implants. All of the implants survived. Within the limitations of this study, autogenous block bone obtained from lateral window sites can be used as novel donors for the resolution of wide bony defects around implants.

Bone Graft Packing and Its Association with Bone Regeneration in Maxillary Sinus Floor Augmentations: Histomorphometric Analysis of Human Biopsies

Research in maxillary sinus floor augmentation (MSFA) focussed on the optimisation of microstructural parameters such as microporosity and particle size of bone substitute particles (BS). However, little is known about the impact of BS packing and the corresponding (void) interparticular space on bone regeneration. The aim of this study was to characterise the spatial distribution of BS and its association with BS integration 6 ± 1 months after MSFA. Histological thin-ground sections of 70 human sinus biopsies were histomorphometrically analysed: In serial zones of 100 µm proceeding from the sinus floor (SF) up to the apical end of the biopsy, we measured the distribution of BS particles within these zones in terms of volume (BSV/TV), number and size of BS particles, interparticle spacing (BS.Sp) and bone-to-BS contact. BS particles were not homogeneously distributed over the length of biopsies: The first 200 µm directly adjacent to the SF represented a zone poor in BS particles but with high osteogenic potential. Graft packing density increased from the SF towards the apical part of the AA. Integration of BS particles was inversely associated with the distance to the SF and the graft packing density. A high packing density through excessive compaction of BS particles should be avoided to optimise the macrostructural environment for bone regeneration.

Customized Titanium Mesh for Guided Bone Regeneration with Autologous Bone and Xenograft

The augmentation of the alveolar crest after the loss of one or several teeth can be carried out using different bone augmentation techniques. These techniques include bone distraction, ridge expansion, bone block grafts, etc. Guided bone regeneration is an alternative to increase the volume of the hard tissues for the subsequent placement of the implants in the optimal three-dimensional position. The objective of this paper is to show a case report of the use of customized titanium mesh for posterior vertical bone regeneration. Case report and Results: A 59-year-old woman comes to rehabilitate edentulous spaces with implants. After taking the anamnesis and the intra and extraoral exploration, a vertical and horizontal bone defect is observed in the third quadrant. After the radiological study with CBCT, a bone height of 6.04 mm to the inferior alveolar nerve and a width of the bone crest of 3.95 mm was observed. It was decided to carry out a regeneration with a preformed titanium mesh (Avinent^®, Santpedor, Spain) and four microscrews (Avinent^®, Santpedor, Spain). The flap was closed without tension. Regular check-ups were performed without complications. At 7 months, the mesh was removed and two osteoingrated implants (Avinent^®, Santpedor, Spain) were placed with a torque greater than 45 N/cm and an ISQ of 82 and 57 N/cm, respectively. The bone gain obtained was 1.84 and 1.92 mm in width and 4.2 and 3.78 mm in height for positions 3.5 and 3.6. The newly formed bone, obtained by trephine, was well-structured and histologically indistinguishable from the previous bone. Conclusion: The use of a customized pre-formed titanium mesh together with the mixture of autologous bone and xenograft is a feasible and predictable technique for vertical bone regeneration.

Custom Bone Regeneration (CBR): An Alternative Method of Bone Augmentation-A Case Series Study

We performed this clinical study in order to evaluate the reliability of the Guided Bone Regeneration (GBR) surgical technique through the use of customized CAD CAM titanium meshes (Yxoss CBR^® Reoss) in order to show an alternative method of bone augmentation.

MATERIALS AND METHODS

Nine patients presenting 10 bone defects were referred to solve oral dysfunction due to edentulous atrophic ridges. Guided bone regeneration was performed with titanium meshes combined with autogenous bone grafting and heterologous bovine bone mineral grafting, and exclusively a "poncho technique" soft tissue approach for all the cases. After a mean 9 months of graft healing (range 6-12 months), titanium meshes were removed, and implant surgery was subsequently performed. The results we obtained were positive in terms of volumetric increases in height, length and thickness of the atrophic ridges without biological complications detectable before implant surgery.

RESULTS

Out of nine, one site met titanium mesh exposure: however, in all 10 sites a three-dimensional volumetric bone implementation was obtained. The statistical results were estimated by uploading and superimposing cbct scans before and after CBR surgery for each patient, so it was possible evaluate the maximum linear vertical and horizontal bone gain through dedicated Cad Cam software (Exocad GmbH^®). The average horizontal gain was 6.37 ± 2.17 mm (range 2.78-9.12 mm) and vertical gain was 5.95 ± 2.06 mm (range 2.68-9.02 mm). A total of 18 implants were placed into the grafted sites with a 100% survival rate (clearly they are relative percentages to be compared to the short time elapsed).

CONCLUSIONS

The results we obtained in this study suggest that this CBR procedure (Yxoss^® by Reoss) is reliable and safe for bone regeneration to allow implant-prosthetic restoration in horizontal, vertical and combined bone defects. The soft tissue management is diriment: all the cases were managed with a "poncho" flap approach to decrease exposure complication.

Characterization of a cotton-wool like composite bone graft material

Bone graft materials are applied in patients to augment bone defects and enable the insertion of an implant in its ideal position. However, the currently available augmentation materials do not meet the requirements of being completely resorbed and replaced by new bone within 3 to 6 months. A novel electrospun cotton-wool like material (Bonewool^®, Zurich Biomaterials LLC, Zurich, Switzerland) consisting of biodegradable poly(lactic-co-glycolic) acid (PLGA) fibers with incorporated amorphous ß-tricalcium phosphate (ß-TCP) nanoparticles has been compared to a frequently used bovine derived hydroxyapatite (Bio-Oss^®, Geistlich Pharma, Wolhusen, Switzerland) in vitro. The material composition was determined and the degradation behavior (calcium release and pH in different solutions) as well as bioactivity has been measured. Degradation behavior of PLGA/ß-TCP was generally more progressive than for Bio-Oss^®, indicating that this material is potentially completely resorbable. Graphical abstract.

Grafting biomaterials associated to topical glucocorticoid: effects on pre-osteoblastic cells (MC3T3-E1)

The topical glucocorticoid budesonide has been prescribed before and after sinus lift surgery as adjuvant drug treatment for maxillary sinus membrane inflammation. However, there is no study on the effects of budesonide on the regenerative process of bone grafting biomaterials. We investigated the effect of the association of budesonide with some biomaterials on the growth and differentiation capacity of pre-osteoblastic cells (MC3T3-E1 subclone 4). Xenogeneic (Bio-Oss and Bio-Gen) and synthetic hydroxyapatites (Osteogen, Bonesynth, and HAP-91) were tested in conditioned medium (1% w/v). The conditioned medium was then supplemented with budesonide (0.5% v/v). Cell viability was assessed using the MTT assay (48, 96, and 144 h), and mineralized nodules were quantified after 14 days of culture using the Alizarin Red Staining. Alkaline phosphatase activity was assessed through the release of thymolphthalein at day seven. All biomaterials showed little or no cytotoxicity. The Bio-Gen allowed significantly less growth than the control group regardless of the experimental time. Regarding differentiation potential of MC3T3-E1, the HAP-91-conditioned medium showed remarkable osteoinductive properties. In osteodifferentiation, the addition of budesonide favored the formation of mineral nodules when cells were cultured in medium conditioned with synthetic materials, whereas it weakened the mineralization potential of cells cultured in xenogeneic medium. Regardless of whether budesonide was added or not, Osteogen and Bio-Oss showed higher alkaline phosphatase activity than the other groups. Budesonide may improve bone formation when associated with synthetic biomaterials. Conversely, the presence of this glucocorticoid weakens the mineralization potential of pre-osteoblastic cells cultured with xenogeneic hydroxyapatites.

Bone morphogenetic protein-2 incorporated calcium phosphate graft promotes peri-implant bone defect healing in dogs: A pilot study

Objectives

The evaluation of three different drug delivery modes of bone morphogenetic protein‐2 (BMP‐2) in healing peri‐implant bone defects in beagle dogs. BMP‐2 was incorporated in or onto calcium phosphate (CaP) granules in various ways: (i) directly on the outer layer of granules CaP: as an adsorbed depot; (ii) during the entire precipitation process of CaP: an internally incorporated depot; or (iii) during the biomimetic coating precipitation of BMP‐2 on the surface of CaP granules: as a coating incorporated depot.

Material and Methods

After extraction of the lower molars and wound healing in 6 male beagle dogs, 36 implants were placed (n = 6 animal per group). Peri‐implant bone defects were induced. The following treatment groups were evaluated: no treatment; air abrasive surface cleaning (SC) using hydroxyapatite; SC and the subsequent filling of the defect with CaP without BMP‐2; SC plus the subsequent filling of the defect with CaP adsorbed BMP‐2; SC plus the subsequent filling of the defect with CaP internally incorporated BMP‐2; SC plus the subsequent filling of the defect with CaP coating incorporated BMP‐2. Histological and histomorphometric analyses were carried out to quantify and compare the changes in bone tissue surrounding the treated implants.

Results

In Group 1 with no treatment, four implants were lost. Group 5 with the SC and the subsequent filling of the defect with internally incorporated BMP‐2 biomimetically prepared CaP (BioCaP), whereby the BMP‐2 is incorporated in the entire volume of all BioCaP particles, showed overall the best results to regenerate bone around the implants.

Conclusion

This study concluded that the group treated with SC plus the subsequent filling of the defect with CaP BMP‐2 internally incorporated BMP‐2, whereby BMP‐2 has been incorporated in the entire volume of all CaP particles, showed overall the best results when aiming to regenerate bone around the implants.

Customized Barrier Membrane (Titanium Alloy, Poly Ether-Ether Ketone and Unsintered Hydroxyapatite/Poly-l-Lactide) for Guided Bone Regeneration

Sufficient bone volume is indispensable to achieve functional and aesthetic results in the fields of oral oncology, trauma, and implantology. Currently, guided bone regeneration (GBR) is widely used in reconstructing the alveolar ridge and repairing bone defects owing to its low technical sensitivity and considerable osteogenic effect. However, traditional barrier membranes such as collagen membranes or commercial titanium mesh cannot meet clinical requirements, such as lack of space-preserving ability, or may lead to more complications. With the development of digitalization and three-dimensional printing technology, the above problems can be addressed by employing customized barrier membranes to achieve space maintenance, precise predictability of bone graft, and optimization of patient-specific strategies. The article reviews the processes and advantages of three-dimensional computer-assisted surgery with GBR in maxillofacial reconstruction and alveolar bone augmentation; the properties of materials used in fabricating customized bone regeneration sheets; the promising bone regeneration potency of customized barrier membranes in clinical applications; and up-to-date achievements. This review aims to present a reference on the clinical aspects and future applications of customized barrier membranes.

Titanium Nanosurface with a Biomimetic Physical Microenvironment to Induce Endogenous Regeneration of the Periodontium

The periodontium supports the teeth by dentoalveolar fibrous joints that serve unique oral functions. Endogenous regeneration of the periodontium around artificial teeth (dental implants) provides a cost-effective solution for the extension of healthy life expectancy but remains a challenge in regenerative medicine. Biomimetics can create smart biomaterials that tune endogenous cells at a tissue-material interface. Here, we created a smart titanium nanosurface mimicking the surface nanotopography and micromechanical properties of the tooth root cementum (TRC), which is essential for the induction of dentoalveolar fibrous joints to regenerate the periodontium. After transplantation into the rat renal capsule, only the titanium artificial tooth with the TRC-mimetic nanosurface formed a complex dentoalveolar fibrous joint structure, with bone tissue, periodontal ligament (PDL), and TRC, in the decellularized jawbone matrix. TRC-mimetic titanium implants induce the formation of functional periodontium, even in a jawbone implantation model, which generally causes osseointegration (ankyloses). In human PDL cells, TRC analogousness in the surface mechanical microenvironment regulates matrix mineralization through bone sialoprotein expression and phosphorus metabolism, which are critical for cementogenesis. Therefore, the titanium nanosurfaces with nanotopographical and mechanical microenvironments mimicking the TRC surface induce dentoalveolar fibrous joints for periodontal regeneration by interfacial tuning of endogenous cells.

Characterization of Dental Pulp Stem Cells Response to Bone Substitutes Biomaterials in Dentistry

Bone substitute biomaterials (BSBs) represent a promising alternative to bone autografts, due to their biocompatibility, osteoconduction, slow resorption rates, and the ability to define and maintain volume for bone gain in dentistry. Many biomaterials are tailored to provide structural and biological support for bone regeneration, and allow the migration of bone-forming cells into the bone defect. Neural crest-derived stem cells isolated from human dental pulp (hDPSCs) represent a suitable stem cell source to study the biological effects of BSBs on osteoprogenitor cells involved in the physiological bone regenerative processes. This study aimed to evaluate how three different BSBs affect the stem cell properties, osteogenic differentiation, and inflammatory properties of hDPSCs. Our data highlight that BSBs do not alter cell proliferation and stemness markers expression, nor induce any inflammatory responses. Bone metabolism data show that hDPSCs exposed to the three BSBs distinctively secrete the factors supporting osteoblast activity and osteoclast activity. Our data indicate that (i) hDPSCs are a suitable stem cell source to study the effects of BSBs, and that (ii) the formulation of BSBs may condition the biological properties of stem cells, suggesting their versatile suitability to different dentistry applications.

Utilizing Previously Grafted Sinus as Intraoral Donor Site for Successful Augmentation in Peri-Implant Osseous Defect: A Case Report

The purpose of this case report is to introduce a novel guided bone regeneration (GBR) technique that utilized bone harvested from previously grafted maxillary sinus with deproteinized bovine bone mineral (DBBM) 16 years ago. The patient is a 63-year-old male with hopeless maxillary right molars due to severe bone loss. Two months after the extraction, two bone blocks were harvested with a trephine drill from the lateral wall. One was used for histologic analysis and the other was crushed into particulate forms, which was used for a GBR procedure around an implant at the time of implant placement. The grafted site was then covered with a resorbable collagen membrane. The histological specimen showed newly-formed bone containing residual DBBM particles. The DBBM in the harvested bone was mostly resorbed; DBBM particles comprised only 3.6% of the total bone volume. The final prosthesis was delivered six months post-operatively. No change in crestal bone around the implant was observed throughout the 2 year follow-up period. Within the limitation of the present case report, previously grafted sinus can be a good donor site for further harvesting for a successful GBR procedure.

Effects of ultraviolet irradiation on beta-tricalcium phosphate as a bone graft substitute

Surface modification of various materials using ultraviolet (UV) irradiation improves their wettability. The purpose of this study was to investigate the wettability of a β-tricalcium phosphate (TCP) surface and the composition changes and bioactivity of β-TCP after UV irradiation. We applied 172 nm UV treatment to a β-TCP surface and measured the contact angle before and after UV irradiation. Energy-dispersive X-ray and Fourier transform infrared spectroscopy examinations were performed on the β-TCP disk with or without UV treatment. In an adhesion test of bone marrow cells using β-TCP disks with and without UV irradiation, cell attachment was measured 10, 30, 50, and 70 h after β-TCP insertion. UV-irradiated β-TCP osteogenesis and absorption of bone substitutes were evaluated using hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining in a rabbit sinus model. The contact angle on the TCP surface decreased from 70° to 10° owing to UV irradiation. Conversely, UV irradiation did not change the composition of carbon, oxygen, and phosphorus. In the cell adhesion test, UV-irradiated β-TCP significantly increased cell adhesion compared with UV-unirradiated β-TCP after 10 to 30 h of culture. In the rabbit sinus model, TRAP staining showed that UV-irradiated β-TCP significantly increased the number of TRAP-positive cells compared with unirradiated β-TCP granules in the central part of β-TCP. Our results indicate that the UV irradiation of β-TCP improves its clinical utility for surgical bone augmentation in the oral and maxillofacial region.

In Vitro Toxicity of Bone Graft Materials to Human Mineralizing Cells

Bone graft materials from synthetic, bovine, and human sources were analyzed and tested for in vitro cytotoxicity on dental pulp stem cells (DPSCs) and osteosarcoma cells (Saos-2). Raman spectroscopy indicated significant amounts of collagen only in human bone-derived materials, where the mineral to protein ratio was 3.55 ± 0.45, consistent with bone. X-ray fluorescence revealed tungsten (W) concentrations of 463 ± 73, 400 ± 77, and 92 ± 42 ppm in synthetic, bovine, and human bone chips, respectively. When these chips were added to DPSCs on tissue culture plastic, the doubling times after two days were the same as the controls, 16.5 ± 0.5 h. Those cultured with synthetic or bovine chips were 96.5 ± 8.1 and 25.2 ± 1.4 h, respectively. Saos-2 was more sensitive. During the first two days with allogeneic or bovine graft materials, cell numbers declined. When DPSC were cultured on collagen, allogeneic and bovine bone chips did not increase doubling times. We propose cytotoxicity was associated with tungsten, where only the concentration in human bone chips was below 184 ppm, the value reported as cytotoxic in vitro. Cells on collagen were resistant to bone chips, possibly due to tungsten adsorption by collagen.

Effect of an "Autogenous Leukocyte Platelet-Rich Fibrin Tooth Graft" Combination around Immediately Placed Implants in Periodontally Compromised Sites: A Randomized Clinical Trial

Objective

Autogenous tooth bone graft (ATBG) was suggested as a source for bone grafting materials, especially as they have similar chemical composition to bone. This study goal was to assess the clinical and radiographic consequences of ATBG with or without L-PRF on bone deposition around immediate implants placed in periodontally hopeless sites.

Materials and Methods

26 patients, with periodontally diseased teeth, underwent random assignment to receive the surgical protocol either with L-PRF over ATBG around immediately inserted implants (test group) or without it (control group). Clinical examination was observed. Radiographically, bone changes horizontally and vertically to determine marginal bone loss (MBL) and mesiodistal bone changes were made at the base line and 6 and 9 months after implant insertion. Statistical analysis utilizing paired Student's t-test was used for comparing results within the same group, whereas an independent-sample t-test was used for intergroup variable comparison.

Results

All implants met the criteria of success without any complications at the follow-up period. Nonsignificant differences were detected between horizontal bone alterations in both groups at 6 and 9 months (P > .001). The test group showed statistically significant lower MBL than the control group (P < .001). The mesiodistal bone gain in the test group was significantly higher than that of the control group at the 6-month period (P < .001). The mesiodistal bone loss in the control group was significantly higher than that of the test group at the 9-month period (P < .001).

Conclusion

The ATBG- L-PRF combination therapy enhances new bone formation and appeared to be a favorable procedure with immediate implant placement, particularly in severe periodontitis cases.

Free-Hand versus Surgical Guide Implant Placement

One of the most key areas of dentistry is dental implant surgery. The use of digital equipment and software in dentistry has developed considerably in recent years compared to other fields of medicine. Since examining the advantages and disadvantages of each approach, along with case studies, can help physicians make informed decisions, this review study aims to raise the awareness of dentists to make easier decisions about using guided or free-hand surgery. When planning for a dental implant, one of the most challenging questions that doctors face is which method to use (guided surgery or free-hand). Choosing the right method, such as other clinical considerations, will depend on the individual circumstances of each patient and the preference of the treating physician. Free-hand surgery is a cost-effective method in which the flap is reflected, and, according to the doctor's diagnostic information, an implant is placed, which in many cases is a useful method. Guided surgery has the highest level of accuracy and control, in which osteotomy is designed and printed through a digital surgery guide, and depending on the complexity of the case and the patient's anatomy, it has a higher level of value than free surgery. The surgical guide helps the surgeon make the implant surgery more accurate, safer, simpler, at a lower cost, and in less time. In fact, there are patterns that convey information about the position of the tooth to the dentist before the implant is placed.

Innovative Concepts and Recent Breakthrough for Engineered Graft and Constructs for Bone Regeneration: A Literature Systematic Review

Background: For decades, regenerative medicine and dentistry have been improved with new therapies and innovative clinical protocols. The aim of the present investigation was to evaluate through a critical review the recent innovations in the field of bone regeneration with a focus on the healing potentials and clinical protocols of bone substitutes combined with engineered constructs, growth factors and photobiomodulation applications. Methods: A Boolean systematic search was conducted by PubMed/Medline, PubMed/Central, Web of Science and Google scholar databases according to the PRISMA guidelines. Results: After the initial screening, a total of 304 papers were considered eligible for the qualitative synthesis. The articles included were categorized according to the main topics: alloplastic bone substitutes, autologous teeth derived substitutes, xenografts, platelet-derived concentrates, laser therapy, microbiota and bone metabolism and mesenchymal cells construct. Conclusions: The effectiveness of the present investigation showed that the use of biocompatible and bio-resorbable bone substitutes are related to the high-predictability of the bone regeneration protocols, while the oral microbiota and systemic health of the patient produce a clinical advantage for the long-term success of the regeneration procedures and implant-supported restorations. The use of growth factors is able to reduce the co-morbidity of the regenerative procedure ameliorating the post-operative healing phase. The LLLT is an adjuvant protocol to improve the soft and hard tissues response for bone regeneration treatment protocols.

The Application of Beta-Tricalcium Phosphate in Implant Dentistry: A Systematic Evaluation of Clinical Studies

The demand for synthetic graft materials in implant dentistry is rising. This systematic review aims to evaluate the survival rate of dental implants placed simultaneously with bone regeneration procedures using the material β-tricalcium phosphate, one of the most promising synthetic graft materials. The electronic search was conducted in PubMed, Scielo, and the Cochrane Central Register of Controlled Trials. Five randomized clinical trials, one non-randomized controlled clinical trial and four observational studies without control group were include. Implant survival rate and other clinical, radiographic, and histological parameters did not differ from those of implants placed simultaneously with another type of graft material, or placed in blood clots or natural alveolar ridges. Based on the available literature, β-tricalcium phosphate seems to be a promising graft material in implant dentistry. Nevertheless, more randomized clinical trials, with long follow-up periods, preoperative and postoperative CBCT, and histological analysis, are necessary to assess its long-term behavior.

Effectiveness of dental implantation with the partial split-flap technique on vertical guided bone regeneration: a retrospective study

PURPOSE

This study aimed to evaluate the effectiveness of the partial split-flap technique with a K-incision on vertical guided bone regeneration (vGBR) and to retrospectively analyze the clinical and radiographic outcomes of dental implantation using this approach.

METHODS

In total, 78 patients who received 104 dental implants with vGBR, categorized as (1) pre-GBR and post-implantation and (2) simultaneous GBR and implantation, were enrolled. Data analysis was based on periapical radiographs, clinical photos, and dental records. The 2-sample t-test was used to compare the 2 surgical procedures.

RESULTS

The baseline vertical bone level, augmented bone height (ABH), and treatment duration were significantly higher in the pre-GBR procedure group. The survival rates of the implants were 96.1% and 94.8% in implant- and patient-based analyses, respectively. In Cox regression analysis, high rates of implant failure were found in the presence of ABH of ≥4 mm, smoking, and diabetes.

CONCLUSIONS

Within the limitations of this retrospective study, the partial split-flap technique using a K-incision for vGBR showed stable clinical outcomes and favorable dental implant survival.

Modified Synthesis and Physicochemical Characterization of a Bioglass-Based Composite for Guided Bone Regeneration

Objectives

Bioglass composites and polymers are materials of great interest for the medical and dental areas due to their properties, combining the bioactivity of ceramic materials and the mechanical properties of polymers. The purpose of the present study was to develop and to characterize the physicochemical and morphological properties an experimental bioglass-based ternary composite composed associated with sodium carboxymethylcellulose (Na-CMC) and polyvinyl alcohol (PVA). The compatibility of functional groups with bioglass was previously evaluated. The composite was then synthesized and evaluated in terms of morphology, elemental composition, compressive strength, porosity, and bioactivity.

Materials and Methods

The bioglass was previously synthesized using a sol-gel route and characterized using FTIR analysis to identify the functional groups. The bone graft composite was then synthesized associating the bioglass with PVA, surfactant Triton X, and Na-CMC. The composite was then morphologically characterized using SEM/EDS. The porosity of the composite was analyzed using µCT, which also provided the composite compression strength. The composite was then evaluated in terms of its bioactivity using SEM/EDS analyses after immersion in SBF for 12, 24, 48, and 72 h.

Results

FTIR analysis confirmed, among other components, the presence of Si–O–Ca and Si–O–Si bonds, compatible with bioglass. SEM analysis exhibited a composite with a porous structure without spikes. The elemental mapping confirmed the presence of Si, Ca, and P in the composite. µCT analysis demonstrated a porous structure with 42.67% of open pores and an average compression strength of 124.7 MPa. It has also demonstrated ionic changes in the composite surface after immersion in SBF, with increasing detection of Ca and P as a function of time, highlighting its chemical bioactivity.

Conclusions

It can be concluded that the proposed bioglass-based composite presents a three-dimensional, well-structured, chemically bioactive porous structure, mechanically resistant for being reinforced with polymeric phases, with promising results as a synthetic bone graft, which makes it suitable for guided bone regeneration.

Clinical applications of concentrated growth factors combined with bone substitutes for alveolar ridge preservation in maxillary molar area: a randomized controlled trial

PURPOSE

To evaluate the clinical effects of concentrated growth factors (CGFs) combined with bone substitutes for alveolar ridge preservation (ARP) in the maxillary molar area.

METHODS

Thirty-six patients who underwent extraction of the upper molars were recruited and randomly divided into three groups: 1. Grafted with CGFs combined with deproteinized bovine bone mineral (DBBM) and covered with CGFs membrane (CGFs/DBBM group), 2. Grafted with DBBM alone and covered with collagen membrane (DBBM group), 3. Control group spontaneous healing. The area of the alveolar bone in center (C-), mesial (M-) and distal (D-) section was compared with preoperative in radiography. Bone cores were obtained for histopathology observation and comparison.

RESULTS

In C-, M- and D-section, the alveolar ridge area in all three groups was significantly reduced at 8 months postoperatively compared to the baseline (P < 0.05). The alveolar ridge area declines in the CGFs/DBBM group (C-12.75 ± 2.22 mm2, M-14.69 ± 2.82 mm2, D-16.95 ± 4.17 mm2) and DBBM group (C-14.08 ± 2.51 mm2, M-15.42 ± 3.47 mm2, D-16.09 ± 3.97 mm2) were non-significant differences. They were significantly less than the decline in the control group (C-45.04 ± 8.38 mm2 M-31.98 ± 8.34 mm2, D-31.85 ± 8.52 mm2) (P < 0.05). The percentage of newly formed bone in the CGFs/DBBM group (41.99 ± 12.99%) was significantly greater than that in DBBM group (30.68 ± 10.95%) (P < 0.05). The percentage of residual materials in the CGFs/DBBM group (16.19 ± 6.63%) was significantly less than that in the DBBM group (28.35 ± 11.70%) (P < 0.05).

CONCLUSION

Combined application of CGFs and DBBM effectively reduced the resorption of alveolar ridge and resulted in more newly formed bone than the use of DBBM with collagen membranes.

Impact of simultaneous placement of implant and block bone graft substitute: an in vivo peri-implant defect model

Background

Insufficient bone volume around an implant is a common obstacle when dental implant treatment is considered. Limited vertical or horizontal bone dimensions may lead to exposed implant threads following placement or a gap between the bone and implant. This is often addressed by bone augmentation procedures prior to or at the time of implant placement. This study evaluated bone healing when a synthetic TiO₂ block scaffold was placed in circumferential peri-implant defects with buccal fenestrations.

Methods

The mandibular premolars were extracted and the alveolar bone left to heal for 4 weeks prior to implant placement in six minipigs. Two cylindrical defects were created in each hemi-mandible and were subsequent to implant placement allocated to treatment with either TiO₂ scaffold or sham in a split mouth design. After 12 weeks of healing time, the samples were harvested. Microcomputed tomography (MicroCT) was used to investigate defect fill and integrity of the block scaffold. Distances from implant to bone in vertical and horizontal directions, percentage of bone to implant contact and defect fill were analysed by histology.

Results

MicroCT analysis demonstrated no differences between the groups for defect fill. Three of twelve scaffolds were partly fractured. At the buccal sites, histomorphometric analysis demonstrated higher bone fraction, higher percentage bone to implant contact and shorter distance from implant top to bone 0.5 mm lateral to implant surface in sham group as compared to the TiO₂ group.

Conclusions

This study demonstrated less bone formation with the use of TiO₂ scaffold block in combination with implant placement in cylindrical defects with buccal bone fenestrations, as compared to sham sites.