Preliminary Study Of Er:YAG And Er, Cr:YSGG Ablation Enamel And Dentin

With the development of laser technology, laser has already been involved into almost every fields of the endodontic treatment. What concerns us most is that how to get the best surface appearances of dental hard tissues after the ablation of lasers. In this paper, a preliminary in vitro study of the laser ablated characteristics of human teeth was carried out.In this study, Er:YAG laser and Er,Cr:YSGG laser were used to ablate the dental hard tissues. We observed the characteristic changes of the ablated tissues and then obtained the ablation threshold values of the two types of laser. The ablation threshold value of Er:YAG laser in dental enamel is 3.19-4.36J/cm2, in dental dentin, it is 2.97-3.56J/cm2. As to Er,Cr:YSGG laser, the ablation threshold values are 4.12-4.80 J/cm2 in enamel and 2.69-3.66 J/cm2 in dentin.We have also studied the ablated appearences of human dental dentin under different laser energy densities of Er:YAG laser and Er,Cr:YSGG laser. We observed the morphological changes of the ablated dental hard tissues and found the relationship between the energy density and ablation crater diameter, depth and volume that the ablation efficiency is in a significant linear correlation At the last of this study, we evaluated the scavenging effect of the two types of laser on smear layer on the root canal walls created by hand instrumentation. Both the two lasers were efficient in cleaning the smear layer, leaving the dentinal tubules open and no melting appearances detected.