Alveolar ridge augmentation by distraction osteogenesis

Distraction osteogenesis is an alternative method for reconstructing atrophic alveolar bone. Fourteen patients underwent vertical alveolar distraction by the LEAD SYSTEM-Endosseous Alveolar Distraction System (Stryker Leibinger, Kalamazoo, MI). An alveolar segmental osteotomy was carried out and the vertical distraction device was mounted. In patients with an extensive alveolar defect, two distraction devices were placed in order to better control the vector of elongation in both bone edges. The distraction was started on the fourth postoperative day at a rate of 0.8 mm/day for 10-16 days, followed by a consolidation period of 60 days. Vertical distraction osteogenesis (VDO) was completed successfully in all patients with segment lengths in the range of 8 to 13 mm and with an average of 10.3 mm. Subsequently, the devices were removed and 23 threaded titanium dental implants were placed for osteointegration. Earlier mineralization in the vertically distracted area was seen radiographically during the consolidation period. In a follow up of 6-20 months after the distraction, 22 implants were successfully osteointegrated while one implant failed due to improper distracted segment stability. As a result of alveolar distraction, a segment of mature bone was transported vertically in order to lengthen the crest for better implant anchorage, either for aesthetic purposes or for functional prosthetic requirements. The main advantages of VDO are: (1) augmentation of alveolar bone height with new bone formation and simultaneous expansion of the soft tissues; (2) no bone harvesting is necessary; (3) the technique has a lower morbidity rate compared with conventional techniques; (4) it makes the insertion of longer dental implants feasible.     

Alveolar ridge preservation: an overview of systematic reviews

The aim of this overview was to assess the methodological quality of systematic reviews of randomized clinical trials on alveolar ridge preservation after a tooth extraction. During March 2020, two independent reviewers performed an electronic search of the PubMed (MEDLINE), Scopus, Web of Science, and Cochrane Library databases to identify all relevant systematic reviews including randomized clinical trials on alveolar ridge preservation. A manual search of articles in renowned journals was also conducted. The methodological quality of the included reviews was determined using the AMSTAR-2 tool. From the 53 initially retrieved studies, 11 were finally included: three systematic reviews and eight systematic reviews with meta-analyses. The methodological quality of the included reviews was low or critically low. Higher quality clinical studies should be conducted prior to performing further reviews and these should meet the methodological requirements that are fundamental to this type of research.     

Histologic comparison of healing after tooth extraction with ridge preservation using mineralized versus demineralized freeze-dried bone allograft

Background: Allografts, such as demineralized freeze‐dried bone allograft (DFDBA) and mineralized freeze‐dried bone allograft (FDBA) are commonly used by clinicians for ridge preservation procedures. The primary objective of this study is to histologically evaluate and compare the healing of non‐molar extraction sockets grafted with DFDBA versus FDBA for ridge preservation. The secondary aim of this study is to compare dimensional changes in ridge height and width after grafting with these two materials. Materials: Forty patients were randomly divided into two groups of 20. Extraction sockets were filled with either FDBA or DFDBA. To minimize variables associated with the organ donor and with tissue processing, all of the graft material was procured from a single donor; the only difference in the two materials was the percentage mineralization of the final bone graft. A 2‐mm‐diameter core biopsy was taken from each grafted site ≈19 weeks after grafting. Histomorphometric analysis was performed to determine percentage of vital bone, residual graft particles, and connective tissue (CT)/other non‐bone components. Results: There were no significant differences when comparing changes in alveolar ridge dimensions of the two groups. There was no significant difference in percentage CT/other between groups. DFDBA had a significantly greater percentage of vital bone at 38.42% versus FDBA at 24.63%. The DFDBA group also had a significantly lower mean percentage of residual graft particles at 8.88% compared to FDBA at 25.42%. Conclusion: This study provides the first histologic and clinical evidence directly comparing ridge preservation with DFDBA versus FDBA in humans and demonstrates significantly greater new bone formation with DFDBA.     

Clinical results of alveolar ridge augmentation with mandibular block bone grafts in partially edentulous patients prior to implant placement

A group of 15 partially edentulous patients who needed alveolar ridge augmentation for implant placement, were consecutively treated using a two-stage technique in an outpatient environment. A total of 18 alveolar segments were grafted. During the first operation bone blocks harvested from the mandibular ramus or symphysis were placed as lateral or vertical onlay grafts and fixed with titanium osteosynthesis screws after exposure of the deficient alveolar ridge. After 6 months of healing the flap was re-opened, the screws were removed and the implants placed. Twelve months after the first operation implant-supported fixed bridges could be provided to the patients. Mean lateral augmentation obtained at the time of bone grafting was 6.5 +/- 0.33 mm, that reduced during healing because of graft resorption to a mean of 5.0 +/- 0.23 mm. Mean vertical augmentation obtained in the 9 sites where it was needed was 3.4 +/- 0.66 mm at bone grafting and 2.2 +/- 0.66 mm at implant placement. Mean lateral and vertical augmentation decreased by 23.5% and 42%, respectively, during bone graft healing (before implant insertion). Mandibular sites showed a larger amount of bone graft resorption than maxillary sites. All the 40 implants placed were integrated at the abutment connection and after prosthetic loading (mean follow-up was 12 months). No major complications were recorded at donor or recipient sites. Soft tissue healing was uneventful, and pain and swelling were comparable to usual dentoalveolar procedures. A visible ecchymosis was present for 4 to 7 days when the bone was harvested from the mandibular symphysis. From a clinical point of view this procedure appears to be simple, safe and effective for treating localised alveolar ridge defects in partially edentulous patients.     

Histologic comparison of healing after ridge preservation using human demineralized bone matrix putty with one versus two different-sized bone particles

Background: Ridge preservation can minimize the loss of alveolar bone subsequent to tooth extraction in preparation for implant therapy. The purpose of this study is to histologically and clinically compare human demineralized bone matrix (DBM) putty with one size of bone particles (SPS) to human DBM putty with two different sizes of bone particles (multiple particle sizes [MPS]) in ridge preservation after molar extractions. Methods: Molar tooth extraction and ridge preservation were performed in 20 participants for each treatment group. Approximately 20 weeks after grafting, core biopsies were obtained during implant placement and analyzed under light microscopy. Specimens were analyzed for the percentage area of vital bone, residual graft particles, and non‐mineralized structures (connective tissue/other non‐mineralized tissue [CT]). Changes in alveolar ridge dimensions were also determined. Results: Sixteen participants in the SPS group and 14 in the MPS group completed the study. The SPS group had a mean of 49% vital bone, 8% residual graft, and 43% CT. The MPS group had 53%, 5%, and 42%, respectively. Patients in both groups lost a mean of <1 mm alveolar height on the buccal and lingual aspects and <1.5 mm of total ridge width. There were no statistically significant differences between the two groups for any clinical or histologic parameters. Conclusion: The results of this study suggest that addition of larger bone particles to DBM putty does not offer additional benefit in the preservation of alveolar bone after the extraction of molar teeth.     

Synthetic polymeric barrier membrane associated with blood coagulum,human allograft,or bovine bone substitute for ridge preservation: a randomized,controlled, clinical and histological trial

During the normal healing process, an extraction site may lose significant bone volume, making implant placement problematic. Quantitative evaluations of the amount of bone maintained by socket preservation with various materials are limited. The objective of this study was to evaluate, both clinically and histologically, the extent of alveolar bone preservation by blood coagulum (BC) and the potential additional benefits of bone allograft material (AL) versus the state-of-the-art bovine bone mineral (BB), covered by a polyethylene glycol (PEG) barrier, in extraction socket grafting procedures. Adult patients (n = 32) with single-rooted teeth indicated for extraction were treated (45 sites). After atraumatic extraction, the sockets were filled with BC, AL, or BB and covered with a synthetic PEG barrier membrane. Changes in bone height and width were measured clinically and the amount of bone formed and residual graft particles were measured histologically after 6 months. Changes in ridge width at 6 months were ?1.5 mm for AL versus ?2.5 mm for BB and ?2.3 mm for BC. New bone formation amounted to 47.8%, 33.3%, and 28.2% at BC-, AL-, and BB-treated sites, respectively. Using AL with the PEG barrier preserved the ridge width at 6 months better than BB or BC and resulted in similar amounts of bone histologically to BB.     

Clinical performance of tooth root blocks for alveolar ridge reconstruction

This systematic literature review set out to investigate the clinical outcomes of autogenous tooth root blocks used for ridge augmentation: survival rates, block resorption, implant survival, post-surgical complications, and histology findings. This review followed PRISMA guidelines. An automated search was made in four databases, supplemented by a manual search for relevant articles published before December 2020. The quality of evidence provided was assessed with the Newcastle–Ottawa Quality Assessment Scale and the Joanna Briggs Institute Critical Appraisal tool. Seven articles fulfilled the inclusion criteria and underwent analysis. The articles included a total of 136 patients, who received 118 autogenous tooth root blocks and 26 autogenous bone blocks showing block survival rates of 99.15% and 100%, respectively. Tooth root blocks presented a mean bone gain that was similar to autologous bone blocks but showed less resorption. The implant survival rate was 98.32% for autogenous tooth root blocks. Reconstruction of alveolar crests by means of autogenous tooth root blocks appears to be a satisfactory option for single-tooth gaps and low grades of bone atrophy in terms of the survival of the bone block and the implants placed subsequently. More research providing long-term data is needed to confirm these findings.     

Histomorphometric comparison of maxillary pristine bone and composite bone graft biopsies obtained after sinus augmentation

Introduction: Sinus grafting is a technique oriented to facilitate implant placement in posterior atrophic maxillae. Several modifications of the original technique and a wide variety of materials have been proposed; most of them associated with implant survival rates. However, the quality of the bone obtained after the application of certain grafting materials has not been fully elucidated yet. The aims of this multicenter study were to analyse histomorphometrical samples obtained 6 months after sinus grafting using a composite graft consisting of anorganic bovine bone (ABB)+ autologous bone (AB), and to compare these samples with maxillary pristine bone biopsies. Material and methods: Ninety maxillary sinus augmentations were performed for delayed implant placement (N=90) in 45 consecutive patients (test group). Bone cores were harvested 6 months after grafting for histomorphometric and ultrastructural study. Control pristine bone biopsies were taken from the posterior maxilla of 10 patients (control). Bone radiographic changes were assessed up to 24 months after implant loading. Results: The total mean values after analysis of test cores revealed a proportion of 46.08±16.6% of vital bone, 42.27±15.1% of non‐mineralized connective tissue, and 37.02±25.1% of the remaining ABB particles. Significant bone remodeling activities were noticed in sinus grafting samples when compared with pristine bone. A statistically significant difference was observed in the number of osteoid lines between two groups, with higher values in the test one (15.1±11.48% vs. 2.5±2.2%, P=0.0005). Ultrastructural study showed that vital trabecular bone was in intimal contact with ABB particles. Radiographic analysis revealed that the higher the proportion of remaining ABB, the lower the total vertical resorption of the graft. Conclusion: Sinus grafting constitutes an excellent model for the study of de novo bone formation patterns and graft consolidation, when a combination of different bone substitutes is applied. The combination of ABB+AB yields highly satisfactory outcomes from both a clinical and a histologic perspective. To cite this article:
Galindo‐Moreno P, Moreno‐Riestra I, Ávila G, Fernández‐Barbero JE, Mesa F, Aguilar M, Wang H‐L, O'Valle F. Histomorphometric comparison of maxillary pristine bone and composite bone graft biopsies obtained after sinus augmentation.
Clin. Oral Impl. Res. 21 , 2009; 122–128.     

Clinical efficacy of autogenous dentin grafts with guided bone regeneration for horizontal ridge augmentation: a prospective observational study

The aim of this study was to evaluate the efficacy of autogenous dentin grafts with guided bone regeneration (GBR) for horizontal ridge augmentation. Nineteen patients with dentition and bone defects in whom tooth/teeth extraction was indicated were recruited. Autogenous teeth were prepared, fixed on the buccal sides of the defects, and covered with bone powder and resorbable membranes before implantation. The horizontal bone mass at 0 mm (W1), 3 mm (W2), and 6 mm (W3) from the alveolar crest was recorded using cone beam computed tomography, before, immediately after, and 6 months after dentin grafting. All adverse effects were recorded. The implant stability quotient (ISQ) was measured 6 months after implantation. Twenty-eight implants were placed 6 months after dentin grafting. At this time point, the bone mass was 4.72 ± 0.72 mm (W1), 7.35 ± 1.57 mm (W2), and 8.96 ± 2.38 mm (W3), which was significantly different from that before the surgery (P < 0.05). The bone gain was 2.50 ± 0.72 mm (W1), 4.10 ± 1.42 mm (W2), and 4.56 ± 2.09 mm (W3). No soft tissue dehiscence or infection was observed. Overall, 26.3% of the patients experienced severe pain after dentin grafting. The ISQ was 78.31 ± 6.64 at 6 months after implantation. Autogenous tooth roots with GBR might be effective for horizontal ridge augmentation. This technique could be an alternative to augmentation using autogenous bone grafts.