Marginal adaptation, fracture load and macroscopic failure mode of adhesively luted PMMA-based CAD/CAM inlays

To evaluate marginal adaptation, fracture load and failure types of CAD/CAM polymeric inlays.

Standardized prepared human molars (48) were divided into four groups (n=12): (A) PCG (positive control group); adhesively luted glass-ceramic inlays, (B) TRX; CAD/CAM polymeric inlays luted using a self-adhesive resin cement, (C) TAC; CAD/CAM polymeric inlays luted using a conventional resin cement, and (D) NCG (negative control group); direct-filled resin-based composite restorations. All specimens were subjected to a chewing simulator. Before and after chewing fatigue, marginal adaptation was assessed at two interfaces: (1) between dental hard tissues and luting cement and (2) between luting cement and restoration. Thereafter, the specimens were loaded and the fracture loads, as well as the failure types, were determined. The data were analysed using three- and one-way ANOVA with post hoc Scheffé test, two sample Student's t-test (p<0.05).

Before and after chewing fatigue, marginal adaptation for interface 1 showed significantly better results for TRX and PCG than for TAC (p=0.001-0.02) and NCG (p=0.001-0.047). For interface 2, marginal adaptation for TAC was significantly inferior to TRX (p<0.001) and PCG (p<0.001). Chewing fatigue had a negative impact on the marginal adaptation of TAC and NCG. No significant differences in fracture load were found between all tested groups.

Self-adhesive luted polymeric CAD/CAM inlays showed similar marginal adaptation and fracture load values compared to adhesively luted glass-ceramic inlays.