Different modes of diode laser irradiation: effects on enamel surface and intrapulpal temperature at debonding.

Background: laser aided debonding of ceramic brackets has been proved to be effective in reducing enamel surface damages, though the optimal parameters of laser to be chose is in question. The aim of this study was to investigate the six different regimens of diode laser irradiation on enamel surface characteristics and intrapulpal temperature changes while debonding.

Materials and methods: 90 polycrystalline brackets were bonded to 90 intact extracted premolars. At debonding, teeth were divided into 6 groups (n = 15) and were subjected to the following regimen of diode laser irradiation; G1 = 2 W, continuous wave, G2 = 2.5 W, continuous wave, G3 = 3 W, continuous wave, G4 = 2 W, pulsed mode, G5 = 2.5 W, pulsed mode, G6 = 3 W, pulsed mode. After debonding, the adhesive remnant index, the lengths and frequency of enamel cracks were compared among the groups. 5 teeth out of 15 were randomly selected from each group to assess the intrapulpal temperature changes.

Results: The number of enamel cracks increased significantly in all the specimens after debonding. Enamel crack length increased significantly in all the study groups except G3 and G6. The increase in intrapulpal temperature was significantly below the benchmark of 5.5 C for all the specimens. Significant difference was observed in adhesive remnant index scores among the groups and more than half of the teeth showed a score of 2.

Conclusion: Diode-laser irradiation in pulsed mode or continuous wave at given outputs (2, 2.5, 3 W) were not statistically different in regard to producing enamel surface damages or increasing intrapulpal temperature.