Curing of posterior dental composites - A surface microhardness study

摘要

Background: Adequate cure of the photo activated polymer and sufficient light intensity is important for optimal mechanical properties, polymerization and strength of the composite material. This study establishes the relationship between the light intensities produced by 2 different light curing systems - a Light emitting diode (LED) and a Halogen light curing system, the distance of the curing tip to the composite and its effect on the surface microhardness changes at various depths of 2 dental composite systems. Methodology: Ten samples each of 2 posterior composite materials were prepared at 2 depths using customized moulds and cured at 0mm and 2mm distance from the light source. The Knoop hardness number of the top and bottom surfaces of the blocks were assessed following their respective treatments and subjected to statistical analysis using the paired and unpaired T test (p＜0.01). Conclusions: Proximity of light source to the photo-activated material influenced the surface hardness of the light activated restorative material. LED produced superior surface hardness than the halogen light curing system, though significant variations weren't observed.