title: [A scanning electron microscopy study on morphological changes of Er, Cr: YSGG laser-cutted dental hard tissue].
abstract: OBJECTIVE
  The purpose of this study was to evaluate the morphological changes of Er, Cr: YSGG laser irradiated dental hard tissues by scanning electron microscopy (SEM).
  
  
  METHODS
  12 freshly extracted premolars were treated with 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 treatment resulted in a rather scaly and rough surface. The sections were free of smear layer, with open dentinal tubules. No carbonization and thermal damages were observed. The laser at 6 watt appeared rougher than at 4 watt, occasionally caused micro-cracks.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Oral Medicine, College of Stomatology, China Medical University, Shenyang 110002, China.
authors.forename: Jingtao
authors.initials: J
authors.lastname: Yu
authors.forename: Xingya
authors.initials: X
authors.lastname: Jia
authors.forename: Liyan
authors.initials: L
authors.lastname: Qiao
mesh_terms: D003737:Dental Cavity Preparation / Q000295:instrumentation* / Q000379:methods; D003743:Dental Enamel / Q000528:radiation effects / Q000648:ultrastructure; D003754:Dental High-Speed Equipment; D003804:Dentin / Q000528:radiation effects / Q000648:ultrastructure; D006244:Hardness; D006801:Humans; D066298:In Vitro Techniques; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D014070:Tooth / Q000528:radiation effects / Q000648:ultrastructure*