Filippo Fontana

Clinical outcomes of vertical bone augmentation to enable dental implant placement: a systematic review.

BACKGROUND This review addressed the focused question of what is the predictability of vertical ridge augmentation techniques for patients, who were diagnosed with insufficient alveolar bone volume for the placement of dental implants. MATERIAL AND METHODS A systematic online review of three main databases was performed between 1966 and 1 November 2007. Four groups of vertical bone augmentation techniques have been identified and evaluated: (1) guided bone regeneration, (2) distraction osteogenesis, (3) onlay bone grafting, and (4) an array of different techniques. Data extraction was based on the following outcomes: (a) success and failure rate of the procedure (vertical bone gain/loss), (b) complication rate of the procedure, and (c) implant survival, success and failure rate. RESULTS The initial search identified 189 papers from the electronic database. The review produced seven papers for GBR, 13 reporting distraction osteogenesis, five for onlay bone grafting and three describing different techniques. CONCLUSIONS For the concept of vertical ridge augmentation to enable dental implant placement, there are clinical and histological data supporting its potential use. Given the confined number of investigators using these techniques and the low number of patient treatments reported in the literature, the generalizability of this approach is limited at this time.

Surface‐modified zirconia implants: tissue response in rabbits

AIM To evaluate the bone tissue response to zirconia implants with three different surface modifications in comparison with the oxidized titanium surface with the goal to optimize osseointegration in terms of strength and speed. MATERIALS AND METHODS A total of 18 rabbits with 143 implants were used. One hundred and twenty-three were threaded zirconia ceramic implants with three different surface topographies and 20 modified titanium oxide implants were controls. Each rabbit received eight implants and sacrificed after 3 weeks. The removal torque test (RTQ) and histology were performed. RESULTS Sixteen out of 18 rabbits completed the study with a total of 110 implants. No statistical significance was observed between the chemical modification implants compared with the topographically modified zirconia implant in terms of interfacial shear strength proven by the RTQ applied. No statistical significance was also observed in the bone-to-implant contact between the zirconia implants and the control oxidized implants. CONCLUSIONS The findings suggest that additional specific chemical modifications of the topographically modified zirconia implants do not seem to enhance the bone-to-implant contact and appear not to increase the interfacial shear strength.

Effects of a calcium phosphate coating on the osseointegration of endosseous implants in a rabbit model

OBJECTIVES The aim of the present study was to evaluate a Ca-P coated implant surface in a rabbit model. The Ca-P surface (test) was compared to the titanium porous oxide surface (control) in terms of bone-to-implant contact (BIC) and removal torque value. MATERIALS AND METHODS Two hundred and sixteen dental implants were inserted in the tibia and in the femur of 36 rabbits. One hundred and eight were represented by Ca-P oxidized surface implant and other 108 were titanium porous oxide surface modified implants. Each rabbit received six implants. Animals were sacrificed after 2, 4 and 9 weeks of healing. Each group included 12 rabbits. The femoral implant and the proximal implant of the tibia of each animal were subjected to the histologic analysis and the distal implants of the tibia underwent removal torque test (RTQ). RESULTS Histological analysis in terms of BIC and RTQ did not revealed any significant difference between the Ca-P oxidized surface and the oxidized surface at 2 and 4 weeks. At 9 weeks, the oxidized surface demonstrated better results in terms of RTQ in the tibia. CONCLUSION In conclusion, findings from the present study suggested that the Ca-P coating had no beneficial effect in improving bonding strength at the bone-implant interface either at 2, 4 and 9 weeks.

Twelve-Year Retrospective Follow-Up of Machined Implants in the Posterior Maxilla: Radiographic and Peri-Implant Outcome.

PURPOSE To retrospectively evaluate the survival rate of machined implants in sinus-lifted posterior maxilla after 12 years, with special reference to radiographic outcome and peri-implantitis. MATERIALS AND METHODS From 37 possible candidates, 29 patients with 59 implants were evaluated. Implants were placed in the posterior maxilla in combination with a sinus elevation procedure (27 patients) or 6 months after sinus elevation (2 patients). Marginal bone level changes were radiographically evaluated at baseline and 1, 7, and 12 years post-loading. Probing depth was measured; presence/absence of plaque and bleeding on probing were recorded. RESULTS Four out of 59 implants failed in 4 out of 29 patients (cumulative survival rate = 93.2%). The mean bone loss was 0.78 mm (± 0.88) after 12 years. Changes in the mean bone level were statistically significant between baseline and all the other follow-up intervals (p < .001). Statistically significant differences could be demonstrated for the first- to 12th-year interval (p < .05) and for the seventh- to 12th-year interval (p < 0.001). No statistically significant differences could be demonstrated at the first- to seventh-year interval (p = .32). The mean overall probing depth was 2.9 ± 0.66 mm. Probing depth was moderately correlated with the marginal bone changes at 7 year and after 12 year follow up (p = .05). No signs of peri-implantitis were reported during the 12-year follow-up period. CONCLUSIONS This follow-up demonstrates a very good prognosis when implants with machined surfaces are used. The frequencies of implant failures were very small. Within the limits of the results from this study, the risk of peri-implantitis in the posterior maxilla might be considered a minor problem when implants with machined surfaces are used.

Osseointegrated implants in vertical ridge augmentation with a nonresorbable membrane: a retrospective study of 75 implants with 1 to 6 years of follow-up.

The aim of this study was to retrospectively evaluate 75 implants inserted in vertically augmented bone at the time of or prior to implant placement after 1 to 6 years of prosthetic loading. The study included 21 patients (29 surgical sites). The vertical procedure was performed combining a titanium-reinforced expanded polytetrafluoroethylene membrane with autograft (7 sites), allograft (5 sites), or auto-xenograft (17 sites). Healing was uneventful in 24 surgical sites. Three sites showed premature exposure, and two sites presented an abscess. Two implants were lost, for a cumulative survival rate of 93.6%. Mean bone remodeling at 1, 2, 3, 4, 5, and 6 years was 0.34, 0.72, 1.04, 0.84, 0.56, and 0.61 mm, respectively. The implant success rate was higher with a simultaneous approach (82.5%) compared with a staged approach (66.8%). Implants surrounded by keratinized mucosa revealed a higher success rate (82.1%) than those without it (58.4%).

Management of d-PTFE membrane exposure for having final clinical success

R econstruction of alveolar bone atrophy by means of nonresorbable membrane is a well-known technique. Expanded polytetrafluoroethylene membrane (e-PTFE) classically required perfect soft tissue closure to prevent wound dehiscence. The consequence of membrane exposure ranges from a minor problem necessitating membrane removal to a major problem including treatment failure and implant loss. In the last few years, e-PTFE membrane has been discontinued from the dental market. An alternative to this barrier is the high-density polytetrafluoroethylene (d-PTFE) membrane. It is a nonresorbable device made of a high-density PTFE with submicron (,0.3 lm) porosity size that has been originally tested in postextraction sockets without primary soft tissue closure. Thanks to its structure, the d-PTFE barrier seems to have more resistance to bacterial penetration, protecting the regenerating bone or implant. Some authors have claimed the possibility that this membrane may remain exposed to the oral cavity with reduced risk of possible complications, such as bacterial contamination, infection, and loss of the graft. This article describes the case of a d-PTFE membrane exposure and its management.