2001 Volume 21 Issue 1 Pages 97-100
Objective : The purpose of this study was to evaluate the acquired acid resistance of lased enamel and dentin by Er,Cr:YSGG laser to artificial caries-like lesions, in vitro.Methods : An Er,Cr:YSGG laser was used to irradiate the enamel or dentin samples from 30 extracted human molars at 6 W (67.9 J/cm 2) or 5 W (56.6 J/cm 2) pulse energy, respectively, with or without water mist. Samples were then subjected to 2μl of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36°C. The parts per million (ppm) of calcium ion (Ca 2+) dissolved in each solution was determined by the atomic absorption spectrophotometry, and the morphological changes were investigated by scanning electron microscopy (SEM). Results : The lowest mean Ca 2+ ppm was recorded in the lased samples. SEM observation showed that the lased areas were melted and seemed to be thermally degenerated. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged. Conclusions : The results of this study suggested that Er,Cr:YSGG laser irradiation with and without water mist appears to be effective for increasing acid resistance.
