Fracture Resistance of 3D-Printed Partial and Conventional Veneers

Background: The purpose of this in vitro study was to evaluate and compare the fracture resistance of 3D-printed partial veneers with finish lines at three different locations and conventional full veneers with finish lines at the gingival level. All restorations were digitally designed and 3D printed using a nanoceramic filled resin specifically developed for veneer restorations. Methods: Four maxillary right central incisor typodont teeth were prepared for labial veneers with finish lines at different locations: incisal third (InT), middle portion of the middle third (MmT), lower portion of the middle third (LmT), and conventional veneer with the finish line at the gingival level (CoV). Each preparation was scanned, and 15 casts were 3D printed from each scan. A total of 60 3D-printed veneers were fabricated (n = 15 per group) using a nanoceramic-filled resin designed for veneer restorations. The restorations were cemented to the 3D-printed dies using the manufacturer’s adhesive and resin cement. The specimens were artificially aged with 10,000 thermal cycles between 5 °C and 55 °C, with a dwell time of 30 s, and then loaded to failure using a universal testing machine. Fracture load values were analyzed using one-way ANOVA and the Tukey honestly significant difference post hoc test (α = 0.05). In addition, fracture patterns were evaluated using scanning electron microscopy images for descriptive purposes. Results: The mean fracture resistance of the 3D-printed partial and conventional labial veneers differed significantly depending on restoration design (p < 0.05). Among the partial veneers, the LmT group showed the highest fracture resistance (279.86 N), followed by the MmT group (266.92 N), while the InT group showed the lowest value (179.22 N). The conventional veneer group (CoV) demonstrated higher fracture resistance (404.07 N) than all partial veneer groups. Conclusions: The fracture resistance of 3D-printed partial and conventional labial veneers fabricated with nanoceramic-filled resins differed according to finish line location. Conventional veneers demonstrated higher fracture resistance than all partial veneer designs. The smallest partial veneer, with the margin located in the incisal third, showed lower fracture resistance than the partial veneer designs with finish lines in the middle third.