Color changes in composites according to various light curing sources / 대한치과보존학회지

ABSTRACT

The purpose of this study was to evaluate the color changes of composite resin polymerized with three type of light curing units. Composite resin (Z100, shade A2) were applied in a cylindrical metal mold(2 mm thick, 7 mm diameter). Twenty specimens according to light curing units were made. Group1 the specimens were polymerized with Apollo 95E for 3seconds(1370 mW/cm2). Group2 the specimens were polymerized with XL 3000 for 40seconds(480 mW/cm2). Group3 the specimens were polymerized with Spectrum 800 for 10 seconds(250 mW/cm2) and 30 seconds(700 mW/cm2). The microhardness values(VHN) of upper and lower surfaces specimens after light polymerization were measured for the degree of polymerization. All specimens were stored in distilled water at 60degrees C for 30 days. The color characteristics(L*, a*, b*) of the specimens before and after immersion were measured by spectrophotometer and the total color difference (DeltaE*) was computed. The results obtained were as follows 1. The microhardness values of Group I showed significantly lower than those of Group II and III(p<0.05). 2. In all groups the DeltaE* values presented below 2.0. 3. Group I showed the highest DeltaE* values followed order from highest to lowest by Group II and III (p<0.05).