Fifteen-year outcome of three-unit fixed dental prostheses made from monolithic lithium disilicate ceramic.

OBJECTIVES: The purpose of this prospective study was to evaluate the clinical long-term outcome over 15 or more years of crown-retained fixed dental prostheses (FDPs) made from a lithium disilicate ceramic (IPS e.max Press, Ivoclar Vivadent).

METHODS: Thirty-six three-unit FDPs replacing anterior (16%) and posterior (84%) teeth were inserted in 28 patients. Abutment teeth were prepared following a standardized protocol. The size of the proximal connector of the FDPs was 12 mm (anterior) or 16 mm (posterior). FDPs were cemented either conventionally with glass-ionomer cement (n = 19) or adhesively with composite resin (n = 17). The following parameters were evaluated at baseline, 6 months after cementation and then annually (at abutment and contralateral teeth): probing pocket depth, plaque index, bleeding on probing, and tooth vitality.

RESULTS: Three FDPs were defined as drop-outs. The mean observation period of the remaining 33 FDPs was 167 months (range: 79-225 months). The survival rate (survival being defined as FDPs remaining in place either with or without complications) according to Kaplan-Meier was 48.6% after 15 years. The success rate (success being defined as free of complications and remaining unchanged) was 30.9% after 15 years.

CONCLUSIONS: Fatigue and crack propagation caused by clinical aging in monolithic lithium disilicate ceramics seem to take considerable time, as shown by the presented survival and success rates after 15 years. Further long-term studies are necessary to evaluate the reliability of FDPs made from other all-ceramic materials over a period of 15 and more years.