Experimental studies on the effect of CO₂ laser irradiation on oral tissues

The effect of CO₂ laser irradiation on dog's bone and tooth

Abstract

Small defects were produced in the dog's mandible by CO₂ laser, and surface deposit of carbonized and heat-coagulated tissue elements were debrided. The tissue response was examined histologically immediately, at 2, 4, 8 and 16 weeks following the surgical procedure. Healing was compared with defects produced by a diamond bur, and also with defects lased and not debrided. The debrided defects demonstrated an almost similar rate of healing compared with the defects produced by a diamond bur, which showed more favorable healing compared with the lased and non-treated defects. Dog's canine was also irradiated by CO₂ laser, and the alteration of temperature in pulp cavity was measured in vivo. The tissue response was also examined histologically immediately, at 1, 2 and 4 weeks after irradiation. Temperature rose to 44°C (20W 3 sec) and to 51°C (40W 3 sec) in the center of the pulp. Histological findings of the pulp sugested that the threshold temperature of pulpal damage caused by heat existed between 44°C-51°C. Healing of the pulp was almost favoable, and reparative dentin was observed after 4 weeks.