Laser Bracket Debonding – Tm: YAP, Nd:YAG, and GaAs Diode Laser Evaluation

  • MUDr Ilia Ivanov, Charles University Prague, 2nd Medical School, Department of Orthodontics, Faculty Hospital Motol, Czech Republic
  • ProfMUDr Tatjana Dostalova, Charles University Prague, 2nd Medical School, Department of Paediatric Stomatology, Faculty Hospital Motol, Czech Republic
  • Prof Helena Jelinkova, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague, Czech Republic
  • Jan Sulc, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague, Czech Republic
  • Petr Koranda, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague, Czech Republic
  • Michal Nemec, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague, Czech Republic
  • Mitsunobu Miyagi, Medical Faculty, 4-16-1 Ayashi Chuo, Aoba-ku, Sendai, 989-3128 Japan, Japan

Objective: This study demonstrates the possibility of using laser radiation for ceramic bracket removing.
Methods: Investigation of a diode - pumped Tm:YAP microchip laser, diode pumped Nd:YAG laser, and GaAs diode generating 1.9 µm, 1.44 µm, and 0.808 µm, respectively. Ten human premolars of adolescent patient mean age 13, were used for that study. Ceramic brackets Facination 2, were bonded using the ConTec LC adhesive (both from Dentaurum, Germany) and polymerized by halogen lamp Elipar Free – Light 2 (3M ESPE, Germany). The time of irradiation was 60 to 90s, with and without water cooling. The irradiation was measured with power meter Molectron EPM 2000e with probe PM3. During the procedure, the temperature inside the tooth was recorded by NiCr-Ni thermocouple and 3210 digital thermometer. Simultaneously, the tooth surface temperature was monitored by thermal imager PV320L2E. The surface of the enamel after bracket removal was analyzed by scanning electron microscope JSM 5510 LV Jeol, Japan.
Results: The GaAs diode µm radiation is not effective for debonding. The results for Tm:YAP and Nd:YAG were similar and the bracket can be removed without cracks. The rest of ConTec LC adhesive is visible after bracket removal and still some change did occur in the enamel surface.
Conclusions: From the SEM measurement results the minimum damage was seen at 1W and 60s interval and both continuously running lasers were providing a reasonable dose for bracket tear.