FRACTURE-BEHAVIOR OF CAD/CAM CERAMIC CROWNS BEFORE AND AFTER CYCLIC FATIGUE AGING.

Purpose: To evaluate the fracture-behavior of monolithic crowns made of lithium disilicate (IPS e.max CAD, Ivoclar Vivadent; IniBal LiSi Block, GC Dental) and zirconia-reinforced lithium silicate (Celtra Duo, DeguDent; VITA Zahnfabrik) materials before and aKer cyclic faBgue aging. Materials and Methods: Four groups (n = 22/group) of CAD/CAM fabricated upper incisor crowns were produced. All crowns were luted on metal dies with an adhesive dualcure resin cement (G-CEM LinkForce, GC Dental). Half of the crowns in each group (n = 11) were staBcally loaded unBl fracture, without aging. The remaining crowns were subjected to cyclic faBgue aging for 120,000 cycles (Fmax = 220 N) and then loaded staBcally unBl fracture. The fractured models were then visually examined. Scanning electron microsopy (SEM) and energy-dispersive spectroscopy (EDS) were used to evaluate the microstructure of CAD/CAM ceramic materials. The data were staBsBcally analyzed with two-way ANOVA followed by the Tukey HSD test (a = .05). Results: Before cyclic aging, there was no staBsBcally significant difference in load-bearing capacity among the four groups (P = .371). AKer cyclic aging, load-bearing capacity significantly decreased for all groups (P = .000). While the e.max CAD blocks had significantly higher load-bearing capacity (1061 ± 94 N) than both monolithic ceramic crowns (load-bearing capaciBes of the groups) (P < .05), no significant difference was obtained with the IniBal LiSi Block group (920 ± 140 N) (P = .061). Conclusions: The mechanical performance of monolithic ceramic crowns fabricated from lithium disilicate was befer than zirconia-reinforced lithium silicate aKer cyclic faBgue aging. [ABSTRACT FROM AUTHOR]