In vitro analysis of the fracture resistance of CAD-CAM monolithic zirconia molar crowns with different occlusal thickness

作者：Sorrentino Roberto^*; Triulzio Clementina; Tricarico Maria Gabriella; Bonadeo Giovanni; Gherlone Enrico Felice; Ferrari Marco

来源：Journal of the Mechanical Behavior of Biomedical Materials, 2016, 61: 328-333.

DOI：10.1016/j.jmbbm.2016.04.014

• Zirconia
• Monolithic
• Crown
• CAD-CAM
• Fracture resistance
• Occlusal thickness

Objectives: To compare the fracture resistance and mode of failure of CAD-CAM monolithic zirconia crowns with different occlusal thickness.
Material and methods: Forty CAD-CAM monolithic zirconia crowns with different occlusal thickness were randomly distributed into 4 experimental groups: 2.0 mm (group 1), 1.5 mm (group 2), 1.0 mm (group 3) and 0.5 mm (group 4). The restorations were cemented onto human molars with a self-adhesive resin cement. The specimens were loaded until fracture; the fracture resistance and mode of failure were recorded. The data were statistically analyzed with the one-way ANOVA followed by the Fisher's Exact test with Bonferroni's correction (p=0.05).
Results: The fracture resistance values of all the specimens exceeded the maximum physiological occlusal loads in molar regions. All the crowns showed cohesive microcracks of the zirconia core; only 1 crown with a thickness of 0.5 mm was interested by a complete fracture.
Conclusions: The occlusal thickness of CAD-CAM monolithic zirconia crowns did not influence either the fracture resistance and the mode of failure of the restorations; the occlusal thickness of CAD-CAM monolithic zirconia crowns can be reduced up to a lower bound of 0.5 mm keeping a sufficient strength to withstand occlusal loads; CAD-CAM monolithic zirconia crowns showed sufficient fracture resistance to be used in molar regions, even in a thin configuration (0.5 mm).

• 出版日期2016-8