Load-bearing capacity of soldered and subsequently veneered 4-unit zirconia FDPs

Abstract

Objectives: This study evaluated and compared the impact of soldering on fracture resistance of veneered 4-unit fixed dental prostheses (FDPs).

Materials and methods: Forty-eight 4-unit zirconia frameworks were milled and randomly divided in four groups (n=12). Untreated frameworks served as control, one group underwent thermal treatment, one group was sectioned and soldered in the connector between both pontics and one group was sectioned and soldered centrally in the mesial pontic. All frameworks were veneered with glass-ceramic material in powder build-up technique. The fracture load was determined on two different failure types, namely on chipping of the veneering ceramic and on total fracture of the FDP. Data were analysed using descriptive statistics, one-way ANOVA together with the Scheffé post-hoc test and Weibull statistics (p<0.05).

Results: The mean range of fracture load of chipped FDPs was determined between 655 N and 789 N; no differences between the tested groups were found (p=0.587). The mean fracture load until total fracture ranged in all tested groups from 768 N to 1261 N. Sound FDPs and soldered FDPs in the connector area presented lower mean total fracture load compared to soldered FDPs in the pontic (p<0.001).

Conclusions: Soldered zirconia frameworks showed similar in-vitro performance compared to sound frameworks.