EFFICACY OF LIGHT-CURED LUTING SYSTEMS FOR CAD-CAM MILLED RESIN INDIRECT RESTORATIONS

Abstract

Objective: To evaluate the bond strength of three light-cured luting systems for CAD-CAM milled resin indirect restorations using a shear bond strength test. Materials and Methods: Thirty Brava Block resin cylinders were fabricated using a CAD-CAM milling unit and subjected to surface treatment with 50-μm aluminum oxide airborne-particle abrasion, ultrasonic cleaning, and application of Monobond N silane primer. Specimens were randomly assigned to three groups (Variolink Esthetic LC, RelyX Veneer, and Allcem Veneer APS) and luted according to each manufacturer’s instructions. After light activation, samples were stored at 37°C for 24 hours. Shear bond strength testing was performed, and failure modes were classified. Data were analyzed using ANOVA and Tukey’s post hoc test (α = 0.05). Results: RelyX Veneer and Allcem Veneer APS protocols produced the highest bond strength values to CAD-CAM milled Brava Block resin (p< 0.05), with no significant difference between them (p > 0.05). Variolink Esthetic LC showed significantly lower values (p < 0.05). Cohesive failure within the milled resin predominated across all groups, while Variolink Esthetic LC exhibited a more balanced failure distribution (30% adhesive, 40% cohesive in resin, 30% mixed). Conclusions: The light-cured luting systems RelyX Veneer and Allcem Veneer APS provided superior bond strength to CAD-CAM milled resin compared with Variolink Esthetic LC, supporting their clinical use in indirect adhesive restorations.