A retrospective evaluation of 192 implants placed in augmented bone : long-term follow-up study

The purpose of the present study was to assess the cumulative survival rate (CSR) of 192 implants placed in association with guided bone regeneration (GBR) procedures to evaluate the long-term predictability of this technique. Moreover, the Kaplan Meier survival analysis was applied to the data in order to evaluate predictors of implant failures, including the source of the graft, the type of membrane, and the timing of implant placement. The CSR of the sample was 95.6% over a mean follow-up period of 78 months (range, 1-175 months). Considering the source of graft, a 95.0%, 93.3%, and 97.7% CSR was obtained for demineralized bovine bone mineral (DBBM), autologous, and 1:1 ratio mixture of autologous and DBBM grafts, respectively. The CSR referred to bioabsorbable membranes was 96.5%, whereas 94.6% was the CSR reported for nonresorbable membranes. The CSR of simultaneous surgeries was 96.8%, whereas staged surgeries showed a CSR of 94.5%. According to the data, implants placed in conjunction with GBR procedures presented a satisfying survival rate even in the long term. All the procedures performed with different bone grafts and type of membranes guaranteed optimal results both in one-and two-stage approaches. No statistically significant differences could be detected among the groups; indeed, the use of DBBM associated with resorbable membranes may be suggested to reduce patients' morbidity and treatment time. Therefore, the dental implants placed in association with bone regenerative procedures presented safe and predictable long-term clinical results.