Influence of the mechanical properties of composites for indirect dental restorations on pattern failure.

This study evaluated the fracture pattern of four composites for indirect dental restoration relating to three-point flexural strength, compressive strength and modulus of elasticity (Solidex, Artglass, belleGlass, and Targis). Ten specimens of each composite were tested in a universal testing machine at 0.5 mm/min crosshead speed for flexural strength and 1mm/min for compressive strength. Fracture pattern was classified as complete or partial fracture. Modulus of elasticity was calculated from flexural strength data. Composites polymerized under high temperatures (belleGlass and Targis) had higher flexural strength and elastic modulus values than composites polymerized by light (Artglass and Solidex). However, they failed earlier under compression because they were more rigid and showed partial fracture in the material bulk.