Abstract: Objective To study the effects of LED and halogen curing lights on the cure depth of composite resin of different colors.Methods Standard cylinder samples of FiltekTM Z350 and Premisa light curing composite were prepared for cure depth test. FiltekTM Z350 resin had three colors:A1B,A2B and A3B.Premisa resin had three colors:A1E,A2E and A3E.Composite resin of each color was made into 60 samples.The samples were divided into three groups equally.The three groups were cured by Demi LED curing light,Bluephase○R 20i curing light and ALC-50 halogen curing light respectively.Results The mean depth of the samples cured by Demi LED curing light for 10 s and Bluephase○R20i LED curing light for 10 s exceeded 3 mm.The difference between Demi LED and ALC-50,Bluephase○R20i and ALC-50 was significant,but there was no significant difference between Demi LED and Bluephase○R20i.The difference between A1E,A2E and A3E of Premisa cured by two LED curing lights was significant.Conclusions Under the same conditions,the cure depth of the two LED curing lights curing for 10 s is superior to the performance level of halogen curing light curing for 40 s.The two LED curing lights are suitable for routine oral clinical application.The darkening of composite resin color can makes a difference to the cure depth.

Key words: curing light, composite resin, cure depth, light emitting diode, LED