INFRARED-LASER SOFT-TISSUE ABLATION VERSUS ULTRAVIOLET EXCIMER-LASER - EXPERIMENTAL INTRODUCTION OF THE HOL-YAG-LASER IN ORAL-SURGERY

The in vivo tissue ablation characteristics of a pulsed infrared laser (Hol:YAG, lambda = 2120 nm) and a pulsed excimer laser (XeCl, lambda = 308 nm) were studied in an animal model. Laser energy was delivered via nylon fibers for the Hol:YAG laser and via quartz fibers for the e xcimer laser. Laser incisions were made under precise reproducible con ditions on the sublingual side of the tongue and the gingiva of white rats. Laser surgery was done at two different energy output settings f or the Hol:YAG laser and at one setting for the excimer laser. Histolo gic studies revealed tissue defects with clean contours for both laser types with small zones of necrosis of the adjacent tissue (Hol:YAG: 1 80 mum to 640 mum; excimer: 40 mum to 160 mum) and without carbonizati on. Both laser types function on the principle of photoablation and pe rmit excellent control of tissue ablation. Wound healing was studied o ver a 10-day period and showed complete wound closure by re-epitheliza tion. The in vivo tissue ablation characteristics and the surgical rel iability of the two lasers are compared and discussed with respect to oral and periodontal surgery.