Factors influencing the microhardness of a microhybrid composite.

This study investigated how different photocuring units, exposure times, and ethanol storage affected the depth of cure in a microhybrid composite. Forty composite specimens (each with a depth of 4 mm) were prepared and divided randomly into four groups (n = 10) to receive treatment from a quartz-tungstenhalogen (QTH) curing unit (400 mW/cm2) or a light-emitting-diode (LED) curing unit (180 mW/cm2). The specimens were photocured for either 20 or 40 seconds and stored in the dark for 24 hours at room temperature.

Effects of 6 months of aging in water on hardness and surface roughness of two microhybrid dental composites.

Purpose: This study assessed the effect of 6 months of aging in water on surface roughness and surface/subsurface hardness of two microhybrid resin composites.

Materials And Methods: Filtek Z250 and Charisma were tested. Cylindrical specimens were obtained and stored in distilled water for 24 hours or 6 months, at 37 degrees C.