The Impact of Cement Type on the Fracture Resistance of CAD-CAM Resin-Matrix Ceramic Anterior Crowns.

Background/Objectives: This in vitro study evaluated the fracture resistance of computer-aided design and computer-aided manufacturing (CAD-CAM) resin-matrix ceramic crowns cemented with three adhesive resin cements and three novel resin-modified glass ionomer cements. Methods: Ninety crowns representing a maxillary left central incisor were milled from a resin-based nanoceramic hybrid material (Cerasmart, GC) using a chairside CAD-CAM system (Primescan). The typodont preparation included 1.5-mm incisal reduction, 1.5-mm axial reduction, and a 1.0-mm chamfer finish line. Crowns were cemented onto 3D-printed dies of the preparation and assigned to six groups (n = 15 per group) according to cement type: Multilink Automix (ReMu), Panavia V5 (RePa), RelyX Unicem 2 (ReUn), RelyX Luting Plus (GiLu), GC FujiCem Evolve (GiEv), and Meron Plus QM (GiMe). The cemented restorations were subjected to artificial aging with 10,000 thermocycles at 5 to 55 °C with a dwell time of 30 s. Specimens were loaded in compression to fracture. Scanning electron microscopy (SEM) was used to evaluate fracture patterns. Fracture load was analyzed using one-way ANOVA and post hoc Tukey honestly significant difference (HSD) test (p = 0.001). Results: Fracture resistance differed significantly among cement types. Crowns cemented with adhesive resin cements exhibited higher fracture resistance than those cemented with resin-modified glass ionomer cements. The highest fracture resistance was observed for ReUn, followed by RePa and ReMu, whereas GiEv and GiLu showed the lowest values. Conclusions: CAD-CAM hybrid crowns fabricated from a resin composite-ceramic material demonstrated higher fracture resistance when cemented with adhesive resin cements than with the novel resin-modified glass ionomer cements tested. Among the six cements, ReUn produced the highest fracture resistance, whereas GiEv produced the lowest.