Abstract : For composite resin polymerization and various light curing units are used. The goal of our study aimed to assess the degree of conversion (DC) and temperature increase in nanofilled and nanohybrid composite resins healed by Argon Laser curing lights and Light Emitting Diode. FTIR spectroscopy used to quantify degree of conversion. In Teflon molds, composite resin samples were positioned and cured of the top to measure the rise in temperature. The thermocouple recorded the increase in temperature under samples. Re-The irradiation was done and the temperature was recorded again after the initial radiation and the ambient temperature was reached. For ANOVA and Tukey - HSD single-way testing (significance of 5 percent), both temperature increase and DC data were submitted. The data obtained confirmed DC don't different between curing units or dental composite of the understudy. There was a significantly higher temperature rise in nanohybrid composite resin than in nanofilled composite resin. The lowest temperature rises from argon laser. Light curing units ' energy density was directly correlated with DC. Mostly because of polymerization and curing unit, the type of composite resin and light curing unit had a significant effect on temperature rise.