Effect of Various Light Sources on the Kinetics of Polymerization Shrinkage Strain, and Degree of Conversion of Low Stress Induce Composites

Abstract

Degree of conversion (DC) is one of the most important factors in clinical performance of the resin composite materials. Optimal physical, mechanical and biological properties of resin composite materials are related to a higher DC that is due to the total emitted light energy from the LCUs with proper wavelength in accordance with the photoinitiator of the resin composite materials. On the other hand, the polymerization shrinkage tends to be higher, which can challenge the adhesive interface and lead to gap formation resulting in micro leakage, postoperative sensitivity, and secondary caries. The aim of this study was to compare the effect of various light sources, Light Emitting Diode (LED) and Blue diode-pumped solid-state (DPSS) laser on the on the; Degree of conversion and Kinetics of polymerization shrinkage strain of low stress induce composites (Kalore, Silorane, and Bulk Fill). And to make Finite element analysis to evaluate the stress and the displacement that happened in the tested resin composite materials after compressive and tensile loading. The specimens were divided into three groups; Group I: Tetric Evoceram Bulk Fill. Group II: GC Kalore. Group III: Silorane based composite resin (Filtek P90). Then each group was divided into two equal subgroups according to the type of light curing. Subgroup I: Sample cured using the Light Emitted Diode for 40 sec.