Three-unit CAD/CAM-manufactured lithium disilicate FDPs after an average observation period of 120 months

Abstract

Objective

In recent decades, CAD/CAM-fabricated lithium disilicate restorations have become popular and have been approved for fixed dental protheses (FDPs) up to the second premolar since 2013. This multicenter follow-up study collected long-term clinical data on three-unit anterior and premolar FDPs made of lithium disilicate to evaluate the material's suitability over >10 years.

Methods

Thirty-two patients received a total of 32 three-unit anterior or premolar monolithic lithium disilicate FDPs. In exceptional aesthetically demanding cases, the labial cut back technique was used for minimal additional veneering. The study was conducted at University Hospital Aachen and three external private dental practices. Failure was defined as any event leading to the loss of an FDP. The survival and success rates were calculated using the Kaplan-Meier method. At the last follow-up examination in 2023 and 2024, 17 of the 32 patients (53,1 %) were re-examined.

Results

The average observation period was 10 years and the longest follow-up period was 15 years. The cumulative survival rate after 10 years was 84.4 %. In detail the five failures recorded were due to one fracture of the connector, one repeated loss of retention, two cases of persistent pain and one loss of an abutment tooth. The cumulative success rate was 75 %.

Conclusion

Within the limitations of this study, lithium disilicate for CAD/CAM manufacturing appears to be a reliable material for full-contour three-unit FDPs, provided that the most posterior abutment tooth does not extend beyond the second premolar and that minimum connector thicknesses are maintained. In aesthetically demanding cases, the labial cut back technique combined with additional veneering can be used.

Clinical significance

This study is one of the few to provide long-term data on the clinical performance of three-unit FDPs made from lithium disilicate, specifically examining cases with premolar abutments. The findings highlight the reliability of this material under the specified conditions.