Spectroscopic characterization of enamel surfaces irradiated with Er:YAG laser

The purpose of this study was to investigate the effect of laser irradiation on the enamel surface spectroscopically. Polished bovine enamel surface was irradiated with an Er:YAG laser apparatus and chemically analyzed using X-ray photoelectron spectroscopy (XPS). XPS detected core electron peaks such as carbon (C 1s) and nitrogen (N 1s), as well as calcium (Ca 2s, Ca 2p, Ca 3s, Ca 3p), phosphorous (P 2s, P 2p), and oxygen (O 1s), from the control enamel surface. After irradiation, XPS revealed that the intensity of C Is peak slightly decreased while that of N Is diminished below the detection limit. Detailed C Is narrow scan spectrum of the Er:YAG laser-irradiated enamel surface showed that C-O/C-N, C = O/-CON =, -COO-, and CO₃^2- components, attributed to the specific composition of enamel and any common carbon contamination in surplus, relatively decreased. The binding energies of Ca 2p and P 2p, Δ (Ca 2p, P 2p), and the Ca/P ratio of lased enamel were found to be different from those of non-lased enamel. It was also shown that Er:YAG laser ablation caused surface alterations to the apatitic inorganic components of tooth tissue.