bruxism-simulated dynamic loading of occlusal veneers
The objective of this study was to analyze the effect of bruxism-simulated dynamic loading on debonding of occlusal veneers fabricated from three different CAD/CAM materials: IPS e.max CAD (IvoclarVivadent, Liechtenstein), Vita Enamic (Vita Zahnfabrik, Badsäckingen, Germany) and Bruxzir (Glidewell Laboratoris, CA, USA). Samples were aged in a chewing simulator for 300,000 cycles at an average load of 50 N, simulating one year of physiological chewing. Samples were then fatigued through linearly accelerated lateral fatigue loading for 115,200 cycles with a linearly increasing load from 50 N till 500 N. Loads and number of cycles at failure were recorded and statistically analyzed. Further analysis for determination of Weibull parameters and reliability of the three materials was then performed. Results revealed better performance of Bruxzir occlusal veneers in terms of strength, whereas Vita Enamic showed better results in terms of reliability. It was concluded that zirconia should be used for restoration of excessive tooth loss in severe bruxism.