Overdentures borne on less than four abutments with telescopic crowns: 5-year results of a retrospective clinical study.

ABSTRACT

OBJECTIVE: Retrospective evaluation of the clinical performance of tooth-supported overdentures retained by resilient telescopic crowns with occlusal clearance fit (ODRTC) in severely reduced dentition (1-3 remaining teeth). MATERIALS AND METHODS: A total of 313 ODRTCs were inserted in an undergraduate prosthodontic program (University Medical Center, Goettingen, Germany) between 2000 und 2012. Data regarding 263 ODRTCs in 221 patients were reevaluated (observational period 64.5 ± 34.8 months), and time-dependent survival and success rates (Kaplan-Meier-Estimator) were calculated. The number of the abutment teeth was analyzed as an influencing factor (Cox regression model (p < 0.05)). RESULTS: The 5- and 8-year overdenture survival rates were 62% [CI 0.55; 0.69] and 38% [CI 0.30; 0.45]. The 5- and 8-year success-rates (biologically and technically event-free restorations) were 13% [CI 0.09; 0.17] and 3% [CI 0.01; 0.05]. On the abutment level, the 5- and 8-year survival rates were 55% [CI 0.48; 0.62], and 34% [CI 0.27; 0.42]. The number of abutment teeth significantly influenced the overdenture and abutment survival rates. Restorations with 1 or 2 abutments were significantly associated with an increased number of technical and biological complications (decementation of the primary crown, abutment fracture) compared to ODRTCs with 3 abutments. CONCLUSIONS: The survival and success rates of ODRTCs are significantly influenced by the number of abutments. CLINICAL RELEVANCE For ODRTCs, reduced survival and success rates are expected, especially when only 1 or 2 abutment teeth are included.