Survival of Telescopic Crown Retained Removable Partial Dentures:7-Year Follow-Up

Objectives: To evaluate the clinical long-term survival of telescopic crown retained removable partial dentures (TRPDs) and to identify necessary treatments during the observation time. Methods: A total of 84 patients (52 males, 32 females mean age:47.3) received 148 TRPDs made of either non-precious or precious metal alloys. Informed patient consents were obtained and approved by the school`s ethical committee. Ninety-one TRPDs were retained with parallel-sided crowns and 57 with conical crowns. Technical TRPD failures were noted and analyzed. Coping material type (precious, non-precious), abutment number (1-4), localization (maxilla, mandible), debonding, fracture, crack formation were used for clinical evaluation. Data were collected at baseline,1,2,3,4,5,6 and 7 years' follow-up. Results: Technical problems occurred during the observation time in 36.3% of the conical retained dentures and 41.6% of the parallel-sided retained dentures. Loss of cementation was the most common failure in both cases, while loss of the facings occurred mainly in conical crowns. Technical failures related with the denture base, such as fracture of artificial teeth or the metal framework were independent of the retainer system used. The survival rate was not significantly affected by the location being either in the maxilla (78.2%) or mandible (71.5%) (p=0.06) (64.42 months) [Kaplan-Meier, Log Rank (Mantel-Cox) (Cl=95%)]. Survival rate decreased as the number of the abutments of TRPDs increased (2 abutments:87.3%; 4 abutments :71%). After 7 years 32 failures were observed due to chipping, debonding or fracture and were repaired. In the debonded cases, parallel-sided crowns were mainly debonded from the teeth. Conclusion: The number of technical failures for both double crown retainer systems were insignificant and they were treatable.