Fracture strength of direct and indirect composite veneers after aging: An in vitro study

Abstract

Aim: The number of patients seeking veneers for minor changes in the color, shape, and size of their anterior teeth has increased. On the basis of this requirement, with the advances in physical and optical properties, composite resins have become viable materials to be used for veneers. There is a paucity of studies that highlight the use of composite resins for anterior esthetic rehabilitations. Hence, this study aimed to compare the fracture strengths of direct and indirect composite veneers. Materials and Methods: This study was conducted on a total of 56 maxillary central incisor samples, divided into two groups: direct composite (n = 28) and indirect composite (n = 28) veneers. Tooth preparations were done, and composite veneers were made via the two techniques. Thermocycling was carried out to age the restorations for half the samples from both groups. The fracture test was performed in a universal testing machine where the load was applied from the incisal direction at the veneer–tooth interface. Results: Direct composite veneers showed a mean fracture strength of 485 ± 147 N before and 438 ± 199 N after thermocycling. Indirect composite veneers showed a mean fracture strength of 409 ± 179 N before and 254 ± 135 N after thermocycling. The most common mode of failure for direct composite veneers was veneer chipping and fracture, whereas debonding was most frequently noted for indirect composite veneers. Statistical analysis used: Unpaired t test was used to study the fracture strengths among the two groups before and after thermocycling. The comparison of frequencies of a mode of failure was investigated using the chi-square test. Conclusions: The direct composite resin veneers showed superior fracture strength, both before and after thermocycling.