Success rate of dental implants inserted in autologous bone graft regenerated areas: a systematic review

Background and Aim: To assess the success rate of implants placed in atrophic ridges, regenerated by means of block bone grafts harvested from iliac crest, calvaria or intraoral donor sites (mandibular ramus, chin). Methods and Materials: A systematic review of all prospective and retrospective studies analyzing the success rate of implants placed simultaneously or as a second surgery following ridge augmentation by means of onlay graft technique, compared with implants placed in pristine bone, was performed. To be included, studies had to involve at least five consecutively treated patients and to report clearly specified success criteria. It was also necessary a minimum follow-up period of six months, to allow the observation of potential biological complications during function, rather than early implant failures. In order to assess the success rate of implants in terms of health of periimplant tissues, implant stability, osteointegration and bone resorption, studies reporting only the survival rate of implants, were excluded. Results: From 323 potentially relevant studies, 65 full-text publications were screened and eight were identified as fulfilling the inclusion criteria. The success rate of implants placed in onlay graft regenerated ridges ranged from 72,8% to 97% after follow-up periods ranging from 6 months to 10 years, with all the studies but two, reporting a success rate higher than 84% (range 84–97%). Conclusion: The obtained data demonstrated that the success rate of implants placed in regenerated areas are very similar to those obtained in case of implants placed in pristine bone, and suggested that onlay graft augmentation is a quite predictable technique to allow the placement of implants in severely atrophic areas. Despite that, the current review revealed that there are not many studies providing data on the success rate of dental implants placed in onlay graft augmented ridges and demonstrated, on average, a poor methodological quality. So randomized controlled studies adopting standardized criteria to define success and failure of implants are required and data from this review must be considered indicative