Zirconia Minimally Invasive Partial Retainer Fixed Dental Prostheses: Up To Ten Year Follow-Up

To assess the survival rate of 3 mol % yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) minimally invasive anterior and posterior single and double partial retainer fixed dental prostheses (PRFDPs).

Twenty-three patients (18 women and 5 men, age range: 20 to 66 years) with single-tooth gaps received 28 3Y-TZP PRFDPs. Eight PRFDPs had two partial retainers and one pontic, two PRFDPs had two partial retainers and one pontic with a mesial cantilever, and 18 PRFDPs had one retainer and one cantilever. The abutment teeth were prepared following specific guidelines for all-ceramic restorations, considering existing direct restorations, carious processes, and occlusal conditions. The restorations were made of 3Y-TZP using CAD/CAM technology. Cementation was performed either conventionally, using resin-modified glass-ionomer (n = 6), or adhesively, using dual-polymerized resin cement (n = 22). Kaplan-Meier survival analysis was conducted. A P value of .05 was considered statistically significant.

During the observation period (5.92 ± 1.74 years, minimum = 2 years, maximum = 10 years), three debondings occurred, all in the two-retainer group and the mandible. The survival rates for the two types of intervention were different, with 100% for a single retainer and 70% for a double retainer, but without a significant difference (log-rank test χ²(1) = 0.200, P = .655).

The 3Y-TZP PRFDPs presented in this study showed no failure when bonded and not conventionally cemented. Therefore, they can be used in cases where implant therapy is not possible or indicated.