Retrospective Study of Pterygoid Implants in the Atrophic Posterior Maxilla: Implant and Prosthesis Survival Rates Up to 3 Years

Purpose: Few reports have evaluated cumulative survival rates of implants placed in the pterygoid region in the medium term. The objective of this study was to evaluate success rates of pterygoid implants and prostheses in patients treated in the atrophic posterior maxilla. Materials and Methods: A retrospective study was performed of patients with an atrophic posterior maxilla rehabilitated with pterygoid implants between 1999 and 2010 and followed for at least 36 months after implant loading. Two outcome variables were considered: implant success and prosthesis success. The following predictor variables were recorded: sex, age, implant placement angulation, number and size of implants, prosthetic rehabilitation, bone loss, date of prosthesis delivery, and date of last follow-up. A statistical model was used to estimate the survival rates and associated confidence intervals. Data were analyzed using the Kaplan-Meier method and log-rank test to compare survival curves. Results: A total of 238 titanium implants (172 anterior and 66 pterygoid) were placed in 56 patients. The 3-year overall pterygoid implant survival rate was 99%. The 3-year overall prosthesis survival rate was 97.7%. The mean bone loss around pterygoid implants after 3 years of loading was 1.21 mm (range, 0.31 to 1.75). All patients were wearing the prostheses at the most recent follow-up examination. Conclusion: Placement of implants in the pterygoid region is a viable alternative treatment modality for rehabilitation of patients with an atrophic posterior maxilla. Keywords: atrophic maxilla, pterygoid, pterygoid implants, pterygomaxillary implants