Vertical ridge augmentation with autogenous bone grafts: resorbable barriers supported by ostheosynthesis plates versus titanium-reinforced barriers. A preliminary report of a blinded, randomized controlled clinical trial. Autogenous onlay bone grafts vs. alveolar distraction osteogenesis for the correction of vertically deficient edentulous ridges: a 2-4-year prospective study on humans. Vertical ridge augmentation of the atrophic posterior mandible with interpositional block grafts: bone from the iliac crest versus bovine anorganic bone. Resorbable screws for fixation of autologous bone grafts. Vertical bone augmentation versus 7-mm-long implants in posterior atrophic mandibles. Results of a randomised controlled clinical trial of up to 4 months after loading. Clinical and histologic evaluation of allogeneic bone matrix versus autogenous bone chips associated with titanium-reinforced e-PTFE membrane for vertical ridge augmentation: a prospective pilot study. Bone augmentation versus 5-mm dental implants in posterior atrophic jaws. Four-month post-loading results from a randomised controlled clinical trial. A prospective clinical study of bone augmentation techniques at immediate implants. Alveolar distraction osteogenesis vs. vertical guided bone regeneration for the correction of vertically deficient edentulous ridges: a 1-3-year prospective study on humans.
To compare the efficacy and complications of 2 different techniques for vertical bone augmentation at implant placement: particulated autogenous bone grafts covered either by resorbable collagen barriers supported by osteosynthesis plates (test) or by nonresorbable titanium-reinforced e-polytetrafluoroethylene (e-PTFE) barrier (control).
                Twenty-two partially edentulous patients requiring vertical bone augmentation were randomly allocated to 2 treatment groups of 11 patients each. Early implant failures, the amount of vertically regenerated bone measured intrasurgically, and biologic complications were recorded by an independent assessor blinded to the group allocation. The implant site requiring the most vertical bone regeneration was selected in each patient for the bone gain assessment. Patients were followed from implant insertion with simultaneous augmentation procedure to insertion of the provisional restoration. Paired and independent t tests and Fisher exact tests were conducted to compare means and proportions at the .05 level of significance.
                No patient dropped out or was excluded. Both procedures obtained significant bone gain and achieved the desired results, 2.2 mm (SD 1.5; P < .001) on average for resorbable barriers and 2.5 mm (SD 1.1) for nonresorbable barriers (P < .001). There was no statistically significant difference in bone gain between the 2 procedures (P = .58). Complications occurred in 40% of the patients. There was no difference in occurrence of complications between the procedures (P > .99). Three major complications occurred, 2 in the resorbable group and 1 in the nonresorbable group, which determined the complete failure of the augmentation procedure.
                Both techniques were effective in augmenting bone; however, both were associated with complications. Clinicians and patients must carefully weigh risks and benefits when considering the use of vertical guided bone regeneration. The purposes of this study were to compare: (a) autogenous bone grafts (ABG) and distraction osteogenesis (DO) for their ability in correcting vertically deficient mandibular ridges and their capability in maintaining over time the vertical bone gain obtained before and after implant placement; and (b) the survival and success rates of implants placed in the reconstructed or distracted areas.
                In a 2-year period (2001-2002), 17 patients presenting with vertically atrophied partially edentulous mandibles requiring implant-supported prosthetic rehabilitation, were included in this study. Patients were randomly assigned to two groups. Eight patients (group 1) were treated with ABG harvested from the mandibular ramus, while nine patients (group 2) were treated by means of DO. In group 1, patients received implants 4-5 months after the reconstructive procedure, while in group 2 implants were placed at the time of distraction device removal (approximately 3 months after the completion of distraction). A total of 19 endosseous implants were placed in group 1, and 21 implants were placed in group 2 patients. For both groups, after an additional 3-5-month period, prosthetic rehabilitation was started.
                Bone resorption before implant placement was significantly higher in group 1 (P=0.01), while no statistically significant differences were found between the two groups as far as survival and success rates of implants and peri-implant bone resorption after the start of prosthetic loading were concerned.
                The results suggested that: (a) both techniques may effectively improve the deficit of vertically resorbed edentulous ridges; (b) survival and success rates of implants placed in the reconstructed/distracted areas are consistent with those of implants placed in native bone. To compare the efficacy, complications and patient preference of two different techniques for vertical bone augmentation of the posterior mandible: bone blocks harvested from the iliac crest versus anorganic bovine bone blocks (Bio-Oss(R)) were used as inlays.
                Ten partially edentulous patients, requiring bilateral and vertical bone augmentation of the posterior mandible (having 5 to 7mm of residual crestal height and at least 5mm thickness above the mandibular canal to allow for implant placement) had their posterior mandibles randomly allocated to both interventions. Resorbable barriers were used to cover the grafts. After 4 months, implants were inserted, and after a further 4 months, provisional prostheses were inserted. Definitive prostheses were delivered 4 months later. Prosthesis and implant failures, the amount of vertically regenerated bone measured on computerised tomography (CT) scans, any complications, the time needed to fully recover mental nerve sensitivity and patient preference were all recorded. All patients were followed up for up to 1 month after the delivery of the final restorations.
                Up to 5 months post-loading no patients dropped out or were excluded. Both procedures obtained significant bone gain and achieved the desired results. Four months after grafting, autogenous bone loss was on average 1.1mm (P=0.088) and Bio-Oss 0.6mm (P=0.001). There were no statistically significant differences in bone gain and maintenance among the two procedures. The sides treated with Bio-Oss recovered their full mental nerve sensitivity significantly faster than those treated with autogenous bone (4 versus 6.3 days). Three complications occurred during graft healing; two in the autogenous bone group and one determining the complete failure of the augmentation procedure. No implants or prosthesis could be placed in the planed area. There was no statistically significant differences in the occurrence of complications between the procedures. After implant placement one complication occurred in the autogenous bone group (probably as a consequence of a previous complication). Patients significantly preferred the treatment with Bio-Oss: 3 weeks after augmentation seven patients preferred Bio-Oss and three patients found the treatments to be 'equally good' (odds ratio 0.045 [5% confidence interval (CI) 0.00 to 0.87], P=0.04). One month after delivery of the final prostheses, eight patients preferred Bio-Oss and two patients found the treatments to be 'equally good' (odds ratio 0.03 [95% CI 0.00 to 0.64], P=0.02).
                This pilot study suggests that it might be sensible to use Bio-Oss blocks rather than bone harvested from the iliac crest as the interpositional graft in the treatment of resorbed posterior mandible, as patient discomfort is reduced. The aim of this study was to evaluate the suitability of resorbable screws made of poly (D.L-lactide) acid (PDLLA) for fixation of autologous bone grafts related to graft regeneration and osseointegration of dental implants. In eight edentulous patients suffering from insufficient retention of their upper denture related to a severely resorbed maxilla, the floor of both maxillary sinus and width of the alveolar crest were augmented with an autologous bone graft from the iliac crest. Randomly, the bone graft used to augment the alveolar crest was fixed with two titanium screws on one side and two resorbable screws on the other side (split-mouth design). Three months after the reconstruction, a bone biopsy was taken with a trephine including one resorbable screw (N = 8). Subsequently, six implants were placed in the left and right posterior maxilla. Six months later, at the abutment connection, a bone biopsy was taken including the other resorbable screw (N = 8). The biopsies were processed for light microscopic examination. In addition, clinical parameters were scored. Wound healing was uneventful. Clinically no difference in wound healing was observed between sides treated with either a resorbable or titanium screw. No implants were lost. Six months after implantation, implant retained overdentures could be fabricated in all patients. All patients functioned well with their overdentures (follow-up 22.2 +/- 4.3 months). Three as well as 9 months after insertion (remnants of), the resorbable screws were still visible after reflecting the mucoperiosteum. Histological examination confirmed that a considerable quantity of remnants of the resorbable screws was still present, although areas with some fragmentation of the PDLLA were also observed. The screws were separated by a fibrous tissue layer containing many giant cells from the bone. Particles of PDLLA were observed within these giant cells. This study revealed that resorbable screws made of PDLLA can be used for fixation of bone grafts. The bulk of the PDLLA material is still present after 9 months. To evaluate whether 7-mm-long implants could be a suitable alternative to longer implants placed in vertically augmented bone for the treatment of atrophic posterior mandibles.
                Sixty partially edentulous patients having 7 to 8 mm of residual crestal height and at least 5.5 mm thickness measured on a computed tomography scan above the mandibular canal were randomised to receive either two to three submerged 7-mm-long NanoTite External Hex implants (Biomet 3i) or 10-mm or longer implants (30 patients per group) placed in vertically augmented bone. Bone was augmented with anorganic bovine bone blocks (Bio-Oss) using a sandwich technique and resorbable barriers. The grafts were left healing for 5 months before placing the implants, which were submerged. Four months after implant placement, provisional acrylic prostheses were delivered. Definitive screw-retained metal-ceramic prostheses were delivered 4 months later. Outcome measures were: prosthesis and implant failures, any complications, and time needed to fully recover mental nerve sensitivity. All patients were followed up to the delivery of the final restorations (4 months after loading).
                No patient dropped out. In two patients of the augmented group, there was not enough space to place 10-mm or longer implants as planned and 7-mm-long implants were used instead. The most likely reason for this is that the Bio-Oss blocks fractured in many pieces at placement. One prosthesis could not be placed when planned in the 7-mm group versus three prostheses in the augmented group, because of failure of one implant in each patient. The difference was not statistically significant. All implants were successfully replaced and final prostheses delivered. Four complications (wound dehiscence) occurred during graft healing in the augmented group (one possibly associated with the failure of one implant) versus none in the 7-mm-long implant group. The difference was not statistically significant. No patient suffered from permanent paraesthesia of the alveolar inferior nerve; however, sensitivity was recovered significantly faster in the short implant group.
                The early results of this study suggest that, when the residual bone height over the mandibular canal is between 7 and 8 mm, 7-mm short implants might be a preferable choice since the treatment is faster, cheaper and associated with less morbidity than vertical bone augmentation. These preliminary results must be confirmed by follow-ups of 5 years or more in order to monitor the performance of short implants over time. To compare clinically and histologically an allogeneic bone matrix to autogenous bone chips in the vertical ridge augmentation technique using titanium-reinforced e-PTFE membranes.
                The study protocol was designed to include patients with bilateral posterior mandibular partial edentulism. Patients were treated with a split-mouth design approach: each side was randomly assigned to the test group (titanium-reinforced e-PTFE membrane and allogeneic bone matrix) or to the control group (titanium-reinforced e-PTFE membrane and autogenous bone chips). Different clinical parameters including the amount of vertically regenerated bone (DSB) and biologic complications were recorded. Histomorphometric analysis and the bone-implant contact percentage were performed.
                Five female patients were enrolled in the study. Ten edentulous sites were vertically augmented and 25 implants were inserted (13 test group, 12 control group) with a staged approach. In the test group no membrane was exposed. The mean bone regeneration was 4.70 mm (SD 0.48 mm). All 13 implants appeared clinically stable. In the control group, 1 membrane was exposed after 2 months. The mean crestal bone regeneration was 4.10 mm (SD 0.88 mm). All 12 implants were stable at the abutment connection. Nine biopsy specimens from the regenerated areas were evaluated. Vertical bone regeneration was evident in both groups since all the samples demonstrated trabecular bone with different degrees of maturation and mineralization in the regenerated area.
                Within the limits of this study based on 5 patients, it appears that the behavior of the allogeneic bone matrix is similar to that of autogenous bone chips when used for vertical ridge augmentation by means of guided bone regeneration techniques. Both grafts demonstrated analogous histologic characteristics. Nevertheless, long-term clinical studies are needed to confirm these preliminary results. To evaluate whether short (5 mm) dental implants could be a suitable alternative to augmentation and placement of longer implants (10 mm) in posterior atrophic jaws.
                Thirty partially edentulous patients with bilateral posterior edentulism were included: 15 patients having 5 to 7 mm of residual crestal height above the mandibular canal, and 15 patients having 4 to 6 mm of residual crestal height below the maxillary sinus and bone thickness of at least 8 mm measured on a CT scan. The patients were randomised either to receive one to three submerged 5-mm-long Rescue implants (Megagen) or 10-mm-long implants placed in augmented bone according to a split-mouth design. Mandibles were augmented with interpositional anorganic bovine bone blocks (Bio-Oss) and maxillae with granular Bio-Oss placed through a lateral window under the lifted sinus membrane. Resorbable barriers were used to cover the grafted sites. Grafts were left to heal for 4 months before placing the implants using a submerged technique. Four months after implant placement, provisional reinforced acrylic prostheses were delivered and replaced 4 months later by definitive screw-retained metal-ceramic prostheses. Outcome measures were: prosthesis and implant failures, any complications, time needed to fully recover mental nerve function (only for mandibular implants) and patient preference assessed 1 month after loading. All patients were followed up to delivery of the final restorations (4 months after loading).
                A systematic deviation from the research protocol occurred: the operator used another implant system (EZ Plus, Megagen) for implants 10 mm or longer with a diameter of 4 mm at the augmented sites. No patients dropped out. In 5 patients of the augmented group (all mandibles), there was not enough height to place 10-mm-long implants as planned and shorter implants (7 and 8.5 mm) were used instead. In each group, one prosthesis could not be placed when planned because an implant was found to be mobile at abutment connection: one 5 mm maxillary implant and one 8.5 mm mandibular implant in the augmented group. Five complications occurred: two in the augmented group (one maxillary sinus perforation and one mandibular wound dehiscence after implant placement possibly associated with the failure of one implant) versus three maxillary sinus perforations in the 5-mm-long implant group. The difference was not statistically significant. No patient suffered from permanent disruption of alveolar inferior nerve function, however, significantly more patients had paraesthesia for up to 3 days in the augmented group. There was no statistically significant difference in patient preference with the majority of patients expressing no preference for which treatment they received, finding both of them acceptable. The efficacy of combinations of membranes and autogenous bone grafts at immediate implants were compared in a prospective study. Sixty-two consecutively treated patients each received an immediate implant for a single tooth replacement at a maxillary anterior or premolar site. Dimensions of the peri-implant defect at the implant collar were measured as follows: vertical defect height (VDH), horizontal defect depth (HDD) and horizontal defect width (HDW). Each implant randomly received one of five augmentation treatments and were submerged with connective tissue grafts: Group 1 (n=12)--expanded polytetrafluoroethylene membrane only, Group 2 (n=11)--resorbable polylactide/polyglycolide copolymer membrane only, Group 3 (n=13)--resorbable membrane and autogenous bone graft; Group 4 (n=14)--autogenous bone graft only, and Group 5 (n=12)--no membrane and no bone graft control. At re-entry, all groups showed significant reduction in VDH, HDD and HDW. Comparisons between groups showed no significant differences for VDH (mean 75.4%) and HDD (mean 77%) reduction. Significant differences were observed between groups for HDW reduction (range, 34.1-67.3%), with membrane-treated Groups 1, 2 and 3 showing the greatest reduction. In the presence of dehiscence defects of the labial plate, HDW reduction of 66.6% was achieved with membrane use compared with 37.7% without membranes. Over 50% more labial plate resorption occurred in the presence of a dehiscence defect irrespective of the augmentation treatment used. The results indicate that VDH and HDD reduction at defects adjacent to immediate implants may be achieved without the use of membranes and/or bone grafts. The purpose of this prospective study was to compare vertical guided bone regeneration (GBR) and vertical distraction osteogenesis (DO) for their ability in correcting vertically deficient alveolar ridges and their ability in maintaining over time the vertical bone gain obtained before and after implant placement. Eleven patients (group 1) were treated by means of vertical GBR with autogenous bone and e-PTFE membranes, while 10 patients (group 2) were treated by means of DO. In group 1, six patients received implants at the time of GBR (subgroup 1A), while five patients had implants placed at the time of membrane removal (subgroup 1B). In group 2, implants were placed at the time of distraction device removal. A total of 25 implants were placed in group 1 and 34 implants were placed in group 2 patients. Three to 5 months after implant placement, patients were rehabilitated with implant-borne dental prostheses. The following parameters were evaluated: (a) bone resorption of the regenerated ridges before and after implant placement; (b) peri-implant clinical parameters 1, 2, and 3 years after prosthetic loading of implants; (c) survival and success rates of implants. Bone resorption values before and after implant placement were significantly higher in group 1. The results suggested that both techniques may improve the deficit of vertically resorbed edentulous ridges, although distraction osteogenesis seems to be more predictable as far as the long-term prognosis of vertical bone gain is concerned. Implant survival rates as well as peri-implant clinical parameters do not differ significantly between the two groups, whereas the success rate of implants placed in group 2 patients was higher than that obtained in group 1 patients.
These conclusions are based on few trials including few patients, sometimes having short follow-up, and often being judged to be at high risk of bias. Various techniques can augment bone horizontally and vertically, but it is unclear which are the most efficient. Short implants appear to be a better alternative to vertical bone grafting of resorbed mandibles. Complications, especially for vertical augmentation, are common. Some bone substitutes could be a preferable alternative to autogenous bone. Osteodistraction osteogenesis allows for more vertical bone augmentation than other techniques which on the other hand can allow for horizontal augmentation at the same time. Titanium screws may be preferable to resorbable screws to fixate onlay bone grafts.