DENTIN ABLATION BY HO-YAG LASER - CORRELATION OF ENERGY VERSUS VOLUMEUSING STEREOPHOTOGRAMMETRY

The future use of lasers in endodontics is dependent upon predictable and consistent ablation of dentin. In this pilot study we used an Ho:Y AG laser fiberoptic delivery system to apply laser energy to prepared tooth sections in vitro. Longitudinally sectioned single-rooted human teeth were subjected to single-energy pulses varying from 25 to 1750 m J at a focal length of 1 mm. At different energy levels we observed ch anges in the dentin surface ranging from minute surface pitting to the formation of large craters. Scanning electron microscopy and stereoph otogrammetry were used to determine the relationship between the amoun t of energy applied to dentin and the extent of dentin ablation. Denti n crater formation was quantified by determining surface area, depth, and volume of craters produced. Increases in laser energy were compare d with increases in surface area, depth, and volume of craters produce d within the range of 150 to 1200 mJ. The Ho:YAG laser fiberoptic deli very system used in this study provides an effective means of ablating dentin. Three-dimensional stereophotogrammetry may prove to be a usef ul method for further studies on the effects of laser energy on minera lized tissues.