Mechanical Resistance of Different Dental Ceramics and Composite, Milled, or Printed Materials: A Laboratory Study

Contemporary indirect restorative materials vary in their physical and mechanical properties, necessitating additional research. This investigation aims to compare the mechanical properties (such as fatigue and compressive strength) of indirect dental restorative materials. In an in vitro study, the mechanical behaviour of monolithic onlay restorations made from a lithium disilicate glass–ceramic (Group A), a ceramic-infiltrated composite (Group B), a polymer-based composite resin (Group C), and zirconia (Group D), bonded to a prepared tooth model, was evaluated after ageing and mechanical cycling. The average value of compressive strength (stage of cracking) in each group was as follows: Group A, 871 N; Group B, 728 N; Group C, 2655 N; and Group D, 2005 N. Moreover, the results of the compressive strength test (stage of destruction) in each group were as follows: Group A, 2516.5 N; Group B, 2266 N; Group C, 5670 N; and Group D, 3543 N. An analysis of variance (ANOVA) followed by Tukey’s (HSD) post hoc test was conducted to assess pairwise comparisons among group means. Statistical analysis revealed significant differences between Groups C and D and the others, highlighting the potential of these materials in clinical applications. Based on the average values, it can be concluded that the 3D-printed ceramic-infiltrated composite onlays exhibited the highest compressive resistance values among the materials evaluated. The lithium disilicate glass–ceramic and the ceramic-infiltrated composite are brittle materials, which should be considered when covering teeth with high occlusal stress.