Long-term clinical evaluation of 211 two-unit cantilevered resin-bonded fixed partial dentures.

OBJECTIVES This retrospective study aims to evaluate the long term clinical performance of two-unit cantilevered resin-bonded fixed partial dentures (RBFPDs) relating to their retention, success and survival rate. MATERIALS AND METHODS Prostheses that were placed at least four years previously were clinically reviewed to evaluate retention, success and survival rate. Additional information was also collected, including patient's gender, age and satisfaction on their prosthesis, operator's experience, prosthesis service life, root canal therapy if performed, abutment mobility, bone support, the presence of shim-stock contacts on the abutment or pontic in intercuspal position, and the presence of proximal axial contacts adjacent to the prosthesis. The date of any debonding with subsequent treatment was also recorded. RESULTS A total of 211 two-unit RBFPDs were placed in 153 patients, with a mean service life of 113.2±33.5 months. Twenty-eight prostheses debonded, resulting in a retention rate of 86.7 percent, and another five teeth were extracted with the prostheses, resulting in a success rate of 84.4 percent. 90.0 percent prostheses were functioning (survival rate) by means of rebonding at the time of review. The location of the replaced tooth had a significant effect on the retention of RBFPDs with posterior RBFPDs lower than anterior (p=0.020). Kaplan-Meier analysis revealed 5-, 10- and 15-year cumulative probability of surviving was 0.97, 0.91 and 0.84, respectively. CONCLUSIONS 211 two-unit RBFPDs were observed to have a success, retention and survival rate of 84.4, 86.7 and 90.0 percent, respectively, with a mean service life of 9.4 years. CLINICAL SIGNIFICANCE Based on the clinical results, two-unit RBFPD are shown to be a durable prosthesis over the long term with high patient satisfaction. The posterior prostheses, particularly in the lower arch appeared to have a higher failure rate, and improved design features should be considered.