RESUMEN
PURPOSE: To determine whether the fracture resistance of computer-aided design/computer-aided manufacturing (CAD/CAM) resin-based composites and polymer-infiltrated ceramic network materials cemented on dentin is influenced by the restoration thickness and composite cement application strategy. METHODS: Disc-shaped specimens (Ø = 7 mm) of 0.8 mm and 1.5 mm thicknesses were milled from two CAD/CAM materials: resin-based composite (RBC, Cerasmart 270) and polymer-infiltrated ceramic network (PICN, Vita Enamic). The discs (n = 8 per group) were cemented on flattened dentin using three different cementation strategies: 1) self-adhesive composite cement (RelyX U200) in light-curing mode (LC-SAC), 2) universal adhesive (Single Bond Universal) with composite cement (RelyX Ultimate) in auto-curing mode (AC cement), and 3) adhesive and composite cement as in 2) but in light-curing mode (LC cement). The restorative surface was indented perpendicularly with a compressive load using a universal testing machine until fracture. The fracture resistance (N) of RBC and PICN was separately analyzed using two-way ANOVA and Tukey's post-hoc test (α = 0.05). RESULTS: The fracture resistance of each material was significantly influenced by the material thickness and cementation strategy (P < 0.05). Irrespective of the material type and cementation strategy, thicker materials exhibit higher fracture resistance. For RBC, the fracture resistance of the LC cement group was significantly higher than that of AC cement only at 0.8 mm thickness. For PICN, the LC-cement cementation strategy produced superior fracture resistance, regardless of the restoration thickness. CONCLUSIONS: The fracture resistance of Cerasmart 270 was higher for the thicker material; the fracture resistance of LC cement was higher than that of AC cement at 0.8 mm thickness cemented to dentin. In comparison, LC cement showed the highest fracture resistance for Vita Enamic for both material thicknesses.
RESUMEN
Objectives: This retrospective study evaluated the factors influencing the clinical failure of noncarious cervical lesion (NCCL) restorations. Methods: Patients were routinely treated by undergraduate or postgraduate students and randomly received a clinical recall evaluation. A retrospective study was performed with two experienced calibrated examiners to evaluate NCCL restorations, including the critical parameters of retention, caries, marginal discoloration, and marginal integrity. The factors related to the restoration included gender, age, arch site, tooth position, the presence of occlusal wear facets, caries risk, operator, adhesive strategy, and composite. The clinical failure comparison between the parameters and factors was performed using the binary logistic regression analysis. Results: A total of 460 cervical restorations from 96 patients were evaluated. The adhesive strategy and the presence of occlusal wear facets were the most important factors influencing the parameter failure. Therefore, the highest failure was marginal integrity, in which the gingival marginal integrity failure was 50.7%, and the occlusal marginal integrity failure was 42.4%. Conclusions: The main factors influencing clinical failure for partial loss, marginal discoloration, and marginal integrity were the adhesive strategy and the presence of occlusal wear facets. Therefore, marginal integrity was the most frequent failure parameter.
