AU - Safarcherati, Hengameh AU - Alaghehmand, Homayoun TI - Hardness of composite resin polymerized with different light-curing units PT - JOURNAL ARTICLE TA - Caspian-J-Dent-Res JN - Caspian-J-Dent-Res VO - 1 VI - 1 IP - 1 4099 - http://cjdr.ir/article-1-59-en.html 4100 - http://cjdr.ir/article-1-59-en.pdf SO - Caspian-J-Dent-Res 1 ABĀ  - Introduction: The degree of polymerization depends on the type of light-curing unit. The aim of this study was to compare the hardness of composite resin cured by LED and Halogen light curing units. Methods: In this experimental study, 20 cylindrical samples of Tetric Ceram composite were prepared. Half of them were cured with Ultralume 2 LED and the other half with Astralis 7 Halogen light curing unit. In the depths of 0,1,2 and 3 mm from surface, one point in peripheral and one point in central portion were marked ,then the hardness of these points was measured by Vickers test . The data was analyzed by a pvalue less than 0.05 considered as significant. Results: The mean hardness of samples cured by LED was more than halogen group in different depths and this difference was statistically significant in peripheral points (p=.048) but this was not significant in central points (p=0.644). The mean hardness in both groups had a decreasing trend from surface to the deep parts in central and peripheral parts and this was more in the central parts. Conclusions: Composites cured by LED light curing unit showed more hardness in similar depths, besides the hardness of composites in central parts is more than the peripheral ones in both groups. CP - IRAN IN - Faculty of Dentistry, Babol University of Medical Sciences, Babol- Iran. LG - eng PB - Caspian-J-Dent-Res PG - 32 PT - Research Paper YR - 2012