EVALUATION OF THE VERTICAL MARGINAL GAP OF THREE CAD/CAM CERAMIC SYSTEM AFTER CYCLIC LOADING

Objective: The objective of this in vitro study was to evaluate the marginal accuracy of different CAD/CAM ceramic crowns after thermo-mechanical cyclic loading. Material and methods: The marginal accuracy of a polymer-infiltrated ceramic network (PICN) material (Vita Enamic [VE]) was compared to two machinable glass ceramics; Zirconia-reinforced lithium silicate (Vita Suprinity [VS]) and a lithium disilicate glass ceramic (IPS e.max. CAD, IPS). 30 natural premolar teeth of average size were prepared (n=10 each group) by computer numerical control (CNC) to fulfill the criteria of all ceramic crown design. Optical impressions were taken for each tooth preparation using the CAD/CAM scanner. 30 crowns were milled from ceramic blocks based on the optical data. A total of 30 crowns were fabricated using CAD/CAM system, and divided into three groups (IPS e.max, VE and VS). The vertical marginal gap was measured using stereomicroscope before, after cementation and after thermo mechanical cyclic loading. Results: No statistically significant difference in vertical marginal gap within or between groups of three tested materials before, after cementation and after thermo mechanical cyclic loading. Conclusions: Vertical marginal adaptation of all tested ceramics was within the clinically acceptable values.