Effect of Different light Curing Techniques on Color Stability of Two Resin Composites (An in vitro study)

Purpose: The originality of the present study was to evaluate the effect of different light curing techniques on color stability of two resin composites. Methods the study samples were divided equally into two main groups according to the type of resin composite (microhybrid and nanohybrid) each main group was subdivided into four subgroups according to type of curing modes (halogen, LED in fast mode, LED in soft start mode and LED in pulse mode), Assessment of color was carried out using a portable reflective spectrophotometer over white background before curing, after finishing and polishing, after one and three months storage in artificial saliva at 37c Results after curing Both resin composite materials recorded statistically significant higher color change mean values above the clinically perceivable values varies between (6.69^B  ± 0.4 to 12.58^A ±0.51), after one month (0.267^B±0.1 to 3.847^A±0.14) and after three months (0.46^B±0.07 to 4.1^A±0.11) Conclusions Large color shift occur immediately after polymerization, this color change above the clinically accepted values (∆E > 3.3), Different LED curing modes affect the color stability of composite with non-significant difference and Color stability of composite depended mainly on material composition rather than curing modes.