The purpose of this study was to determine the success rate of implant-retained prostheses placed by prosthodontic residents between 1997 and 2012 and to evaluate the associations between patient classifications and specific restoration characteristics as related to prosthesis success or failure.
A total of 272 prostheses in 119 patients were clinically evaluated. Success was defined as the absence of prosthetic complications or any implant-related complication that affected prosthesis survival. Logistic regression was used to evaluate associations between prosthesis success/failure and a wide array of study variables, adjusting for patient age, sex, and prosthesis longevity.
The overall success rate was 71%, with a mean prosthesis age of 4.5 years (range: 4 months to 16.8 years). Implant single crowns were the most successful prosthesis type (81% success). The most common complications observed were porcelain fractures in fixed dental prostheses (15%) and lack of stability (31%) and retention (29%) in removable dental prostheses. Having a removable prosthesis (versus natural dentition) in the opposing occlusion significantly decreased the odds of success (OR=0.26, 95% CI: 0.11-0.64). Definitively cemented fixed prostheses were more successful than those cemented with an interim cement (OR=4.56, 95% CI: 1.37-15.22).
The overall success rate of the implant-retained prostheses placed in the program was low compared with previously published studies. This study revealed the need for an efficient, comprehensive recall system for patients receiving implant-retained prostheses, either fixed or removable.