1996 Volume 7 Issue 1 Pages 58-66
The purpose of this study was to evaluate the effects of Er: YAG laser irradiation on human extracted root surfaces in vitro, and to compare with Nd: YAG and CO2 laser irradiation. Twelve 5mm×5mm human root slices were prepared for this study. Two areas with 2mm×3mm were marked at both sides to the tooth axis in each slice. One area was irradiated with water cooling and the other without cooling. Three slices were randomly assigned to each of the following 4 different treatment groups: 1) Er: YAG laser treatment; 2) CO2 laser treatment; 3) Nd: YAG laser treatment; 4) Nd: YAG laser treatment to the root surface coated with black stain. Non-lased surfaces served as controls. The pulsed Er: YAG and Nd: YAG laser irradiations were performed for 10 seconds with an energy level of 50mJ at 10pps in the contact mode, holding the 0.6mm contact handpiece at 45 degree angulation to the root surface. The CW CO2 laser was irradiated with an energy level of 0.5W in the non-contact focus mode. After laser irradiation, the specimens were examined with stereoscope and scanning electron microscope. Root surfaces irradiated by Er: YAG laser featured scaly like appearances. Surfaces received CO2 laser irradiation without water cooling exhibited distinct carbonization and many cracks. With the Nd: YAG laser irradiation, charing, melting and lava-like appearance were observed when the laser was irradiated to the black stained surface without water cooling. The results of this study showed that three kinds of laser application to root surfaces resulted completely different morphological changes. We should consider the characteristics of laser and their effects to root surface, using any laser for periodontal treatment such as scaling, root conditioning, and killing of periodontopathic bacteria.
(J. Jpn. Soc. Laser Dent, 7: 58-66, 1996 Reprint requests to Dr. ANDO)
