Scanning electron microscopic analysis of diseased and healthy dental hard tissues after Er:YAG laser irradiation: in vitro study.

The aim of this study was to treat carious lesions, sound dentin, and enamel either with conventional methods or with an Er:YAG laser and to compare the results. Thirty freshly extracted carious human teeth were divided into two groups. In the first group, lesions were treated with burs in a dental handpiece; in the second group, we used the Er:YAG laser with parameters recommended by the manufacturer (Kavo). After treatment, the teeth were prepared for scanning electron microscopic observation. On laser-treated teeth, scaly, flaky, rough surfaces were seen: surfaces were clean with several morphological reliefs that may enhance bonding resin restoration. The Er:YAG laser beam can ablate carious dentin with an energy level of 250 mJ at 2 Hz. Sound dentin can be cut at 300 mJ and 2 Hz; for enamel, 350 mJ and 3 Hz are required. The Er:YAG laser seems to be effective in the treatment of carious lesions and in cavity preparation in vitro.