Comparison of bone grafting materials in human extraction sockets: clinical, histologic, and histomorphometric evaluations

Alternative method to treat oroantral communication and fistula with autogenous bone graft and platelet rich fibrin

Background

Removing a tooth from the jaw results in the occurrence of oroantral communication in beneficial anatomic conditions or in the case of a iatrogenic effect. Popularized treatments of the oroantral communication have numerous faults. Large bone defect eliminates the chance to introduce an implant. Purpose of this work was assessment of the usefulness of autogenous bone graft and PRF in normal bone regeneration in the site of oroantral communication.

Material and Methods

Bone regeneration in the site of oroantral communication was assessed in 20 patients. Bone defects were supplemented autogenous bone graft from mental protuberance in 14 cases and from oblique line in 6 cases. The graft was covered with a PRF membrane.

Results

In the study group in all cases closure of the oroantral communication was observed. The average width of the alveolar was 13 mm and the average height was 12.5 mm. In 3 patients an average increase of alveolar height of 1.5 mm was observed.

Conclusions

This method may be the best option to prepare alveolar for new implant and prosthetic solutions.

Key words:Oroantral communication, oroantral fistula, autogenous bone graft, bone regeneration, platelet rich fibrin.

In vivo evaluation of biofunctionalized implant surfaces with a synthetic peptide (P-15) and its impact on osseointegration. A preclinical animal study

OBJECTIVES

The overall aim of the study was to investigate a biofunctionalized implant surface with electrochemically deposition of hydroxyapatite and the synthetic peptide (P-15) and its effect on osseointegration.

MATERIAL AND METHODS

Three modified implant types of ANKYLOS^® C/X implants were used; (1) machined implants used as negative control (M, n = 20), (2) implants with the FRIADENT^® plus surface (grit blasted and acid-etched) used as positive control (P, n = 20), and (3) implants with a biomimetic surface consisting of hydroxyapatite and the synthetic 15 aminoacids containing peptide P-15 (BP, n = 40). The implants were randomly inserted in the mandibles of 10 beagle dogs following 4 months after tooth extraction (P1-P4). Three animals were sacrificed 2 and 7 days after implant insertion, respectively, and four animals were sacrificed 6 months post implant insertion. Bone-to-implant contacts (BICs) were analyzed via histomorphometrical analyses at five different region of interests (ROIs); two at the middle part on either side of the implant (ROI 1/4), two at the apical part of the implant at each side (ROI 2/3), and one at the tip of the implant (ROI 5).

RESULTS

All implant surfaces showed a high level of osseointegration and osteoconductivity. The cumulative implant survival rate (CSR) was 93.8%, 100% in the M, 85% in the P, and 95% in the BP group. No statistical difference in BICs at ROI 1/4, 2/3, and 5 could be shown between implant types following 2 and 7 days of healing. BIC values increased in all groups over time. After 6 months of healing the BP group showed superiority in BIC in ROI 2/3 (73.2 ± 15.6%) compared to the P (48.3 ± 10.6%) and M group (66.3 ± 30.2%) with a significant difference between BP and P (P = 0.002).

CONCLUSION

It is hypothesized, that the surface biofunctionalization improves peri-implant bone formation and remodeling, leading to an increased bone-to implant contact. However, within the limitations of the study set-up no benefit in the early phase of osseointegration could be established for dental implants with P-15 containing surface in this study.

Beta-tricalcium phosphate/type I collagen cones with or without a barrier membrane in human extraction socket healing: clinical, histologic, histomorphometric, and immunohistochemical evaluation

The aim of this study was to investigate the healing of human extraction sockets filled with β-tricalcium phosphate and type I collagen (β-TCP/Clg) cones with or without a barrier membrane. Twenty patients were divided in two groups: (A) β-TCP/Clg non-membrane and (B) β-TCP/Clg + barrier membrane. Clinical examination and biopsies from the grafted sites were collected 9 months later. Bone samples were analyzed using histomorphometry and immunohistochemistry. The horizontal dimension of the alveolar ridge was significantly reduced 9 months after socket preservation in the non-membrane group. There was bone formation with no significant differences between the two groups in the areas occupied by new bone (A = 42.4%; B = 45.3%), marrow (A = 42.7%; B = 35.7%), or residual graft (A = 9.7%; B = 12.5%). Immunohistochemistry revealed osteonectin expression in both groups. Both groups demonstrated sufficient amounts of vital bone and socket morphology to support dental implant placement after the 9-month healing period. A future trial to evaluate the alveolar outcomes at an earlier 6-month time point rather than the 9 months used in this study would be of interest.

Clinical-radiographic and histological evaluation of two hydroxyapatites in human extraction sockets: a pilot study

After tooth extraction the healing process involves bone resorption and soft tissue contraction, events that can compromise the ideal implant placement with functional and aesthetic limitations. Following tooth extraction, a socket preservation technique can limit bone resorption. This study evaluated two different types of hydroxyapatite (HA) grafting materials placed into fresh extraction sockets, 6 months after tooth extraction, histologically, clinically and radiographically. Ten extraction sockets from 10 patients were divided in two groups: 5 sockets received a biomimetic HA and 5 received nanocrystalline HA. After 6 months, before implant placement, samples from the grafted area were harvested and evaluated clinically, radiographically and histologically. The percentages of bone, osteoid areas and residual material in the two groups were not statistically different. All samples showed great variability with extensive bone formation and total material resorption or amounts of osteoid tissue that filled the spaces between the residual material particles. The authors did not find any differences between biomimetic and nanocrystalline HA and assume that, within the limits of this study, both these materials could be applied into fresh extraction sockets to limit bone resorption. A control material and a much larger sample size are needed to confirm these findings.

Bone formation on carbon nanotube composite

The effects of a layer-by-layer assembled carbon nanotube composite (CNT-comp) on osteoblasts in vitro and bone tissue in vivo in rats were studied. The effects of CNT-comp on osteoblasts were compared against the effects by commercially pure titanium (cpTi) and tissue culture dishes. Cell proliferation on the CNT-comp and cpTi were similar. However, cell differentiation, measured by alkaline phosphatase activity and matrix mineralization, was better on the CNT-comp. When implanted in critical-sized rat calvarial defect, the CNT-comp permitted bone formation and bone repair without signs of rejection or inflammation. These data indicate that CNT-comp may be a promising substrate for use as a bone implant or as a scaffold for tissue engineering.

Comparison of two resorbable membrane systems in bone regeneration after removal of wisdom teeth: a randomized-controlled clinical pilot study

OBJECTIVES

To compare the performance and safety of Inion GTR(TM) Biodegradable Membrane System and Geistlich resorbable bilayer Bio-Gide((R)) membrane in human bone regeneration.

MATERIAL AND METHODS

In a multicenter, split blind, comparative, randomized, prospective, pilot study 15 patients have been randomized at surgery whether to be treated either with Inion GTR(TM) Biodegradable Membrane System on one and Geistlich resorbable bilayer Bio-Gide((R)) membrane on the other side or vice versa after surgical removal of both fully impacted wisdom teeth. During the follow-up visits at week 1, 2 and 6 and at months 3 and 6 the general state, the wound, eventual adverse events and the medication of the patients were assessed. Computed Tomography (CT) scans were performed immediately and 3 months after the surgery, before biopsy collection. Semi-quantitative histological evaluation and histomorphometric analyses were performed according to the ISO 10993-6 standard. New bone formation and membrane integration were evaluated by CT scan measurements. Tissue healing was evaluated clinically and by photographs between the time on teeth extraction and during follow ups.

RESULTS

Five patients were smokers, none drank alcohol. Mild adverse events like wound infection, haematoma or late swelling of the gums occurred in three patients. The trephine bur harvest of bone biopsies under local anaesthesia was uneventful. Whereas specimens from the sites treated with the Inion membrane yielded 17.0% (SD 24%), the Bio-Gide membrane sites yielded 13.5% (SD 15%) of bone tissue density. In sites treated with the Inion membrane, 9.5% of old bone density and 7.5% of newly formed bone could be found, whereas the Bio-Gide((R)) membrane sites showed 3.8% of old bone density and 9.8% of newly formed bone. There were no statistically significant differences between the two groups with respect to the two variables. The osteoid rim was more extended with the Bio-Gide((R)) (6.6 mm) than with the Inion membrane (5.1 mm) but the difference between the two treatments did not reach statistical significance. Highly significant reductions in the area of the defect with both membranes were detected with significant increases in CT density at the immediate inferio-buccal adjacent bone and in the surgical defect area with both membranes. However, there was neither significant change in CT density in the immediate inferior-lingual adjacent bone of the two membranes, nor significant difference between the membranes on any of the four measurements (area of defect: P=0.1354; CT density immediate inferio-buccal adjacent bone: P=0.7615; CT density surgical defect area: P=0.1876; CT density immediate inferio-lingual adjacent bone: P=0.4212).

CONCLUSION

The overall clinical outcome was satisfying and the majority of the patients showed an uneventful healing phase. Both membranes presented similar capacities regarding their barrier function and were associated with analogous bone regeneration. No statistically valid evidence about the superiority of one particular membrane was obtained. For the patient the only difference is that one product is animal derived and the other synthetic.

Comparison of dermal matrix and polytetrafluoroethylene membrane for socket bone augmentation: a clinical and histologic study

BACKGROUND

Remodeling and resorption of the alveolar crest, specifically at the buccal aspect, characterize the healing extraction socket. These result in narrowing and shortening of the alveolar ridge, which compromise esthetics and complicate restoration. Alveolar ridge augmentation has been proposed to facilitate future site restoration by minimizing ridge resorption. Therefore, the purpose of this study was to compare extraction socket healing and alveolar ridge alteration after socket augmentation using bone allograft covered with an acellular dermal matrix (ADM) or polytetrafluoroethylene (PTFE) membrane.

METHODS

Twenty non-smoking healthy subjects were selected. Each subject required maxillary premolar, canine, or central incisor tooth extraction. The extraction sites were debrided and grafted with a mineralized bone allograft that was covered with an ADM or PTFE membrane. Postoperative appointments were scheduled at 2, 4, and 8 weeks. After 16 weeks of healing, final measurements were performed, and trephine core biopsies were obtained for histomorphometric analysis. Implants were placed immediately after biopsy harvesting.

RESULTS

Eighteen subjects completed the study. All sites healed without adverse events and allowed for implant placement. PTFE membranes exfoliated prematurely, with an average retention time of 16.6 days, whereas the ADM membranes appeared to be incorporated into the tissues. Buccal plate thickness loss was 0.44 and 0.3 mm, with a vertical loss of 1.1 and 0.25 mm, for ADM and PTFE, respectively. Bone quality assessment indicated D3 to be the most prevalent (61%). Histomorphometric analysis revealed 41.81% versus 47.36% bone, 58.19% versus 52.64% marrow/fibrous tissue, and 13.93% versus 14.73% particulate graft remaining for ADM and PTFE, respectively. No statistical difference was found between the two treatment groups for any of the parameters.

CONCLUSION

All sites evaluated showed minimal ridge alterations, with no statistical difference between the two treatment modalities with respect to bone composition and horizontal and vertical bone loss, indicating that both membranes are suitable for alveolar ridge augmentation.

ABM/P-15 modulates proliferation and mRNA synthesis of growth factors of periodontal ligament cells

OBJECTIVE

Periodontal regeneration is histologically defined as regeneration of the tooth supporting structures, including alveolar bone, periodontal ligament, and cementum. Cells in the remaining periodontal tissues need optimal conditions if they are to perform their functions in the regeneration process. The present study is an investigation of the molecular effects of ABM/P-15 on human periodontal ligament cells (PDL) in vitro.

MATERIAL AND METHODS

PDL cells obtained from healthy subjects were used for in vitro experiments. Cell proliferation, morphology, and mineralization using Von kossa staining were evaluated. mRNA expressions for transforming growth factor-beta (TGF-beta), insulin-like growth factor-I (IGF-I), basic fibroblast growth factor (b-FGF), vascular endothelial growth factor (VEGF), bone morphogenic protein-2 (BMP-2), platelet-derived growth factor (PDGF), and type 1 collagen (COL1) were assessed on days 3 and 7 using RT-PCR.

RESULTS

ABM/P-15 enhanced proliferation of cultured PDL cells. It increased the mRNA expression of TGF-beta and BMP-2 in cultured PDL cells on days 3 and 7. IGF-I and b-FGF mRNA expressions showed a slight decrease, while PDGF expression was observed to have increased on day 3. VEGF and COL1 mRNA expressions were found not to be different on days 3 and 7. No differences were observed in the mineralization properties of cultured PDL cells treated with or without ABM/P-15.

CONCLUSIONS

Based on the results of this in vitro study, it may be concluded that ABM/P-15 enhanced the regenerative capacity of PDL by regulating specific gene expressions of cells during early wound healing.

Effect of mesenchymal stem cells and platelet-rich plasma on the healing of standardized bone defects in the alveolar ridge: a comparative histomorphometric study in minipigs

PURPOSE

The purpose of this study was to test the effect of the combination of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) incorporated into a fluorohydroxyapatite (FHA) scaffold on bone regeneration in cylindrical defects in the edentulous mandibular ridge of minipigs.

MATERIALS AND METHODS

Two mandibular premolar teeth were extracted bilaterally in 8 adult minipigs. After 2 months, 4 standardized defects of 3.5 mm diameter and 8 mm depth were created in each root site. The defects were randomly grafted with autogenous mandibular bone, FHA alone, PRP-FHA, or MSCs-PRP-FHA. A resorbable collagen membrane was placed over the defect area and the flaps were sutured. The animals were sacrificed 3 months later and biopsy samples were taken from the defect sites for histologic and histomorphometric assessment.

RESULTS

There was no evidence of inflammation or adverse tissue reaction with either treatment. MSCs-PRP-FHA-treated sites showed new vital bone between residual grafting particles. PRP-FHA- and FHA-treated sites showed residual particles in a background of marrow soft tissue with a moderate quantity of newly formed bone. Autogenous bone (46.97%) and MSCs-PRP-FHA (45.28%) produced a significantly higher amount of vital bone than PRP-FHA (37.95%), or FHA alone (36.03%). Further, the MSCs-PRP-FHA-treated defects showed a significantly higher percentage of contact between graft particles and newly formed bone compared with PRP-FHA and FHA group (59.23% vs 48.37% and 46.43%, respectively).

CONCLUSIONS

Our results suggest that, in this animal model, the addition of MSCs to PRP-FHA enhances bone formation after 3 months.

The effect of collagen I mimetic peptides on mesenchymal stem cell adhesion and differentiation, and on bone formation at hydroxyapatite surfaces

Integrin-binding peptides increase cell adhesion to naive hydroxyapatite (HA), however, in the body, HA becomes rapidly modified by protein adsorption. Previously we reported that, when combined with an adsorbed protein layer, RGD peptides interfered with cell adhesion to HA. In the current study we evaluated mesenchymal stem cell (MSC) interactions with HA disks coated with the collagen-mimetic peptides, DGEA, P15 and GFOGER. MSCs adhered equally well to disks coated with DGEA, P15, or collagen I, and all three substrates, but not GFOGER, supported greater cell adhesion than uncoated HA. When peptide-coated disks were overcoated with proteins from serum or the tibial microenvironment, collagen mimetics did not inhibit MSC adhesion, as was observed with RGD, however neither did they enhance adhesion. Given that activation of collagen-selective integrins stimulates osteoblastic differentiation, we monitored osteocalcin secretion and alkaline phosphatase activity from MSCs adherent to DGEA or P15-coated disks. Both of these osteoblastic markers were upregulated by DGEA and P15, in the presence and absence of differentiation-inducing media. Finally, bone formation on HA tibial implants was increased by the collagen mimetics. Collectively these results suggest that collagen-mimetic peptides improve osseointegration of HA, most probably by stimulating osteoblastic differentiation, rather than adhesion, of MSCs.

Bone graft materials

This article examines each class of bone grafting material based on some of the studies in each of the following categories: safety, animal research, periodontal and maxillofacial applications, skeletal grafting, and attempts to qualify the efficacy of each class of material. The article also examines some of the research being done in "tissue engineering" to get a sense of the future of bone grafting.