Abstract
Recently, lasers are extensively applied in many clinical fields of medicine. In the field or dentistry, laser has not been prompted for clinical application until 1975. However, lasers are gradually utilized for clinical fields or dentistry.
The authors have demonstrated that a normal pulse Nd:YAG laser was the most suitable among the lasers to produce a resistance against acid decalcification of human teeth enamel. A combined treatment of laser irradiation and fluoride application onto the enamel obtained most remarkable acid resistance. Fluoride application after laser irradiation produced a greater fluoride uptake in the enamel than fluoride application alone. Similar results acre obtained from the in vitro and in vivo experiments on incipient dental caries with the subsurface demineralization or human enamel. The inhibitory, effect on enamel demineralization and enhancing effect on enamel remineralization of incipient caries lesion were obtained laser irradiation alone and in combination with fluoride.
The mechanism of acquired acid resistance of lased enamel was investigated. The contents of water, carbonate and organic substances were reduced in lased enamel and lased enamel showed a highly positive birefringence, suggesting the formation of 'microspaces' in enamel. It was suggested that laser irradiation might create the microspaces which could act as sites for trap of ions released by an acid attack.
These results suggest that the application normal pulse Nd:VAG laser is a practical and useful procedure for the prevention or dental caries.
Furthermore, a new method of caries removal and cavity preparation without thermal damage using a laser is under development.
