An Investigation In Surface Morphology, Component And Pulp Chamber Temperature Of Dentin Irradiated With Erbium Laser

The laser ablation of dental hard tissue has a wide prospect of applications on cavity preparation, caries removal and other dentistry field. The effect of laser ablation was the most noticed when laser was applied. This paper probed the ablation effect of Er laser acting on the dentin from the yellow race in respect of the changes of surface morphology, structure components and pulp chamber temperature.Firstly, the basic structure and optical property of dental tissue and the basic concept of laser ablation of biological tissue were briefly introduced. The relative mechanism of laser ablation was discussed. The light dosimetry of dental hard tissue ablation was described on the basis of laser parameters. And the potential applications of laser ablation on the dentistry field were summarized.Secondly, experiments on ablation of dental hard tissue in vitro with Er, Cr:YSGG laser were carried out, where the specimen were moved by the motorized translation stage. After irradiation, changes of morphological characteristics of dentin surfaces irradiated with different laser doses were compared based on the observation with SEM. The experiment obtained the optimum laser dosage and the effect of laser irradiation with optimum dosage was compared with that of traditional dental equipments in terms of morphological changes.Again, the influence of Er, Cr:YSGG laser irradiation on the components and microstructure of dentin was investigated respectively by different spectroscopic methods-Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-ray Spectroscopy (EDX). The traditional equipments were selected as a control group. The changes of main elements and groups were found at the selected laser doses.Finally, the temperature rises in the pulp chamber were recorded by thermocouple when dental hard tissue was irradiated by Er:YAG laser with water cooling or without. The temperature rises induced by different laser fluencies and repetitions were also studied.