Abstract:

Objective　The purpose of this studywas to evaluate the morphological changes of Er,Cr:YSGG laser irradiat- ed dental hard tissues by scanning electron microscopy (SEM).Methods　12 freshly extracted premolarswere treatedwith fissure bur, Er,Cr:YSGG laser at 4 watt, Er,Cr:YSGG laser at 6 watt, respectively, and then bisected transversally and longitudinally. The tooth slice were prepared with conventional methods and observed by SEM.Results　Compared with fissure bur, laser treat- ment resulted in a rather scaly and rough surface. The sectionswere free of smear layer, with open dentinal tubules. No carboniza- tion and thermal damages were observed. The laser at 6 watt appeared rougher than at 4 watt, occasionally caused micro-cracks. Conclusion　The utilizing of Er,Cr:YSGG laser can contribute to enhance the bond strength between restorative materials and dental hard tissues. It suggests that higher energy could be applied in cutting enamel, whereas the lower energy in dentin.

Key words: Er,Cr:YSGG laser, dental hard tissue, scanning electron microscopy