Mid-term survival and complications of double-crown-retained removable dental prostheses placed in the dental practice - a retrospective study.

Objectives: Clinical data on the performance of double-crown-retained removable dental prostheses (dcRDPs), especially beyond university studies, are rare. The objective of this retrospective clinical study was to evaluate the survival and complication-freeness probabilities of dcRDPs and to identify risk factors for failure and complications in a dental practice setting.

Materials and methods: Anonymized practice data of 174 patients (56.9% female) fitted with a total of 213 dcRDPs (mean of 3.3 abutment teeth per dcRDP) were evaluated up to 11 years after prothesis placement (mean observation time of 3.9 years). Probabilities of survival and complication freeness were calculated on the prosthesis- and abutment level and visualized using the Kaplan-Meier method. Factors influencing failure and complications were computed using Cox regression analyses (R Ver. 7; alpha < 0.05).

Results: During our observation period, 39 (18%) of the dcRDPs failed. The mean (95% CI) overall survival was 94% (90-97%) after 2 years and 86% (80-92%) after 5 years. DcRDP survival correlated with lower patient age and more abutment teeth (P < 0.05), while other analyzed factors did not. The probability of absence of prosthesis-related complications was 92% after 2 years and 80% after 5 years. The probability of no technical complications of abutments (teeth/implants) was 85% after 2 years and 78% after 5 years, and the probability of no biological complications was 87% after 2 years and 72% after 5 years. In total, 141 dcRDPs (66.2%) faced at least one complication during the observation period.

Conclusions: Double-crown-retained prostheses fitted in a dental practice had acceptable mid-term survival rates and common technical and biological complications that were frequently easily manageable. However, prosthesis performance depended on the quality and number of abutment teeth/implants. Within the limitations of this retrospective analysis, the outcomes we observed in a dental practice are comparable to, albeit slightly worse than, those found in university studies.

Clinical relevance: Evaluation of the clinical performance of dcRDPs fitted in a dental practice is important to estimate durability and complication patterns in order to weigh treatment decisions.