ABSTRACT
AIM: To compare two different laser sources, a KTP laser with a wavelength of 532â¯nm and a Nd:YAG laser with a wavelength of 1064â¯nm, to investigate the relation between laser source and bleaching gel during laser irradiation. METHODS: Extracted human teeth were stained and randomly divided into six groups. Two in-office bleaching gels, Beyond and Opalescence Boost, were applied to stained teeth and then irradiated at either 532â¯nm or 1064â¯nm. The temperature change of pulp chamber was measured. The color change (ΔE*) was evaluated at the following time points: immediately after bleaching, 7, 14 and 30 days after the end of bleaching. RESULTS: Boost irradiated by KTP laser showed the higher temperature increase when compared with Beyond irradiated KTP and Nd:YAG. Boost irradiated by Nd:YAG presented lower temperature increase than by KTP. All groups showed a certain color change. After bleaching, Nd:YAG laser irradiation did not increase the ΔE* value significantly compared with gels without laser (pâ¯>⯠0.05). At each time point, Boost activated by KTP laser showed higher ΔE* value compared with other groups (p < 0.05), but decreased significantly 15 days after the end of bleaching. The other groups showed a relatively small change in ΔE* value after 30 days (p > 0.05). CONCLUSIONS: KTP laser achieved better results than the Nd:YAG laser regarding tooth color change when associated with the Opalescence Boost bleaching gels.
