Purpose: This study evaluated the long-term survival and success rates of dental implants placed with autogenous onlay block bone grafts harvested from the mandibular ramus.

Materials and methods: Patients treated with onlay bone graft from the mandibular ramus due to a severe vertical alveolar defect from 2001 to 2017 were included in this study. The marginal bone loss, success, and survival time of the implants were recorded and analyzed with clinical factors, such as time from bone graft to implant placement, type of implant prosthesis connection, history of periodontitis, and insertion depth.

Results: Seventy-five implants in 40 onlay bone-grafted areas of 38 patients were included, with a mean follow-up period of 102 months (range: 14 to 192 months). Two grafts were removed before implant placement. Of the 75 implants, 11 implants were lost. History of periodontitis and marginal bone loss at 6 months after implant placement were significantly associated with implant success. The receiver operating characteristic curve showed that a marginal bone loss of 0.75 mm after 6 months of implant placement was related to implant success, with a sensitivity of 72.2% and specificity of 89.6%.

Conclusion: Implants placed with onlay bone graft from ramal bone had more frequent biologic complications, and failures may be predicted by measuring the amount of implant bone loss after 6 months of placement.