Reliability estimation for single-unit ceramic crown restorations

Abstract

The objective of this study was to evaluate the potential of a survival prediction method for the assessment of ceramic dental restorations. For this purpose, fast-fracture and fatigue reliabilities for 2 bilayer (metal ceramic alloy core veneered with fluorapatite leucite glass-ceramic, d.Sign/d.Sign-67, by Ivoclar; glass-infiltrated alumina core veneered with feldspathic porcelain, VM7/In-Ceram Alumina, by Vita) and 3 monolithic (leucite-reinforced glass-ceramic, Empress, and ProCAD, by Ivoclar; lithium-disilicate glass-ceramic, Empress 2, by Ivoclar) single posterior crown restorations were predicted, and fatigue predictions were compared with the long-term clinical data presented in the literature. Both perfectly bonded and completely debonded cases were analyzed for evaluation of the influence of the adhesive/restoration bonding quality on estimations. Material constants and stress distributions required for predictions were calculated from biaxial tests and finite element analysis, respectively. Based on the predictions, In-Ceram Alumina presents the best fast-fracture resistance, and ProCAD presents a comparable resistance for perfect bonding; however, ProCAD shows a significant reduction of resistance in case of complete debonding. Nevertheless, it is still better than Empress and comparable with Empress 2. In-Ceram Alumina and d.Sign have the highest long-term reliability, with almost 100% survivability even after 10 years. When compared with clinical failure rates reported in the literature, predictions show a promising match with clinical data, and this indicates the soundness of the settings used in the proposed predictions.

Keywords: CAD; biomechanics.; finite element analysis (FEA); restorative materials; statistics; stress analysis.

© International & American Associations for Dental Research.

Figures

Figure 1.

Theoretical method to predict failure probability for fast fracture and fatigue loadings.

Figure 2.

Contours of maximum principal stress for In-Ceram Alumina core and monolithic ProCAD and failure probabilities at the crown-dentin interface for perfectly bonded and completely debonded cases. (a) Contours of maximum in-plane principal stress for In-Ceram Alumina Core (P = 1,000 N). (b) Contours of maximum in-plane principal stress for monolithic ProCAD (P = 1,000 N). (c) The failure probability at the crown-dentin interface (Empress, Empress II, ProCAD, and In-Ceram Al) under lingual loading as a function of chewing loading for a perfectly bonded case. (d) The failure probability at the crown-dentin interface (Empress, Empress II, ProCAD, and In-Ceram Al) under lingual loading as a function of chewing loading for a completely debonded case.

Figure 3.

Failure probability of veneer and core materials after 5 and 10 years for a perfectly bonded case and after 5 years for a completely debonded case compared with 2 sets of clinical failure rates presented in the literature (higher predictions are indicated by triangular dots, and lower predictions are indicated by diamonds).