Plasma arc versus holgen light curing of ceramic brackets

Bond strength and debonding characteristics of plasma arc curing light compared to halogen curing light when used to bond mechanical base retention ceramic brackets were tested in this study. Brackets were bonded to 50 extracted human maxillary premolars with a composite adhesive and they were divided into two equal groups. A curing time of 3 seconds was used for curing with the plasma arc light, and 20 seconds per bracket with the halogen light. Thermocycling was performed to simulate oral cavity conditions. For shear bond testing; Debonding of 15 brackets from each group was performed on a universal testing machine. There was no significant difference in the shear bond strength of brackets bonded by the two lights. Bond strength was 9.65 ±3.1 MPa for plasma arc curing light and 9.35 ± 2.33 MPa for the halogen light. In both groups the shear bond strength fell in the clinically acceptable range. 10 Brackets from each group were debonded using the debonding plier to test the debonding chraracteristics. Brackets consistently debonded at the bracket-adhesive interface with both types of curing lights. A reasonable amount of composite was always left on the enamel surface thus protecting enamel from detachments. These results indicate that the plasma arc light with a 3 second curing time can be used with mechanical retention base polycrystalline ceramic brackets to produce acceptable bond strength and a safe pattern for bracket debonding. Shear bond strength and ARI score values were comparable to halogen light curing which requires longer curing time.