Fracture resistance of chairside CAD‐CAM lithium disilicate occlusal veneer with various designs after mechanical aging

Abstract

AbstractPurposeThis study evaluated the fracture resistance of chairside computer‐aided design and computer‐aided manufacturing (CAD‐CAM) lithium disilicate crown, onlay, and non‐anatomical occlusal veneer (A‐OV) with and without margin fabricated.Materials and MethodsSixty‐four CAD‐CAM lithium disilicate restorations were designed as (1) complete coverage crown (CCC); (2) A‐OV with margin; (3) non‐A‐OV with margin (NA‐OV‐M); and (4) non‐A‐OV without margin (NA‐OV‐NM), 16 of each. Restorations were crystallized and adhesively luted to resin dies using resin cement. Specimens were then subjected to 400,000 cycles of chewing in a mastication simulator. A universal testing machine was used to apply a compressive load at a crosshead speed of 1 mm/min to the long axis of the tooth with a stainless‐steel sphere until fracture occurred. One‐way ANOVA followed by post hoc tests were used to assess the impact of preparation design on the fracture load of CAD‐CAM lithium disilicate restorations.ResultsThe highest fracture load was recorded for CAD‐CAM lithium disilicate indirect restorations for non‐A‐OVs preparation with margin (2549 ± 428 N) and onlay (2549 ± 293 N) and the lowest fracture load was recorded for CCCs (2389 ± 428 N); however, there was no significant (p = 0.640) between groups.ConclusionsCAD‐CAM lithium disilicate restorations fabricated for anatomical and non‐A‐OV preparation display a fracture resistance similar to CCCs. Conservative partial coverage restorations may be considered an acceptable approach for posterior teeth.