Morphological analysis of dentin tissue after Er, Cr: YSGG laser irradiation

The object of this study is to evaluate the morphological changes of dentin tissue after Er, Cr: YSGG laser Irradiation. The wavelength is 2.78 μm with pulse repetition rate of 20 Hz and pulse duration of 140 μs. The samples extracted from sound intact adult human premolars were cut into 1 mm thick dentin slices, and then polished by abrasive papers. After preparation, specimens were randomly divided into two groups: one group treated with conventional drills (a diamond drill and a fissure bur), and the other group treated with lasers at four different power settings (2W to 3.5W). The morphological alterations produced by the different treatments were observed and compared by scanning electron microscope (SEM). It showed that the dentin surfaces had distinct and characteristic morphological alteration with different power settings. Compared with the samples treated with conventional drills, the irradiated samples revealed an absent smear layer with open dentinal tubules. The ablation of intertubular dentin was more evident than that of peritubular dentin.