Intrapulpal Temperature Increase During Er: YAG Laser-Aided Debonding of Ceramic Brackets

Objective: The purpose of this study was to evaluate the temperature changes in the pulp chamber while using a newly introduced application of Er: YAG laser to debond ceramic brackets in a study model with a pulpal circulation with and without thermocycled samples. Background data: An esthetic alternative to stainless steel brackets, ceramic brackets have been proposed. However, because of their low fracture resistance and high bond strengths, ceramic brackets can cause a problem when they are being removed using conventional techniques. Materials and methods: Experimental Groups A and B were established for samples with or without thermocycling. The same 20 maxillary central incisor and 20 premolar teeth were used in both groups. Pulpal blood microcirculation was simulated using an apparatus described in a previous study. Monocrystalline brackets were bonded by using Transbond XT. In Group A, brackets were debonded using the Er: YAG laser (600 mJ, 2 Hz, long pulse, and no air or water spray) after being stored in distilled water for 24 h. In Group B, brackets were debonded using the same laser system as that used in Group A after being stored in distilled water for 24 h and then thermocycled for a total of 5000 cycles between 5 degrees C and 55 degrees C. The laser irradiation duration and intrapulpal temperature changes were measured. Results: In Group B, the intrapulpal temperature increase of the central incisors was significantly higher than that of the premolar teeth. In the central incisor and premolar teeth groups, there were no statistically significant difference between Groups A and B (p > 0.05). A positive correlation was found between laser irradiation duration and temperature increase (p < 0.01). Conclusions: The use of Er: YAG laser is an effective method for debonding the monocrystalline ceramic brackets. This method can be used safely under the consideration of intrapulpal temperature changes.