title: [Root resection by Er:YAG laser: a scanning electron microscope study].
abstract: OBJECTIVE
  To compare the difference of the surface of root resection by Er:YAG laser, ultrasonic or high-speed handpiece with scanning electron microscope (SEM), and to evaluate the possibility of using Er:YAG laser on the root resection in clinical application.
  
  
  METHODS
  Thirty maxillary central incisors were divided into three groups (Er:YAG laser group, ultrasonic group, high-speed handpiece group), and the root resection were made at root tip 3 mm with Er:YAG laser, ultrasonic instrument or long needle diamond bur according to grouping. The surface of the root resection by SEM in the aspects of debris, smear layer, opened dentinal tubules, cracks and ablation characteristics were compared.
  
  
  RESULTS
  The examination revealed that Er:YAG laser group and ultrasonic group had no or little debris and smear layer and with opened dentinal tubules. High-speed handpiece group had great amount of debris and smear layer and without opened dentinal tubules. Cracks were observed in ultrasonic group and high-speed handpiece group, no in Er:YAG laser group. There were ablation characteristics in ultrasonic group and high-speed handpiece group, but no in Er:YAG laser group.
  
  
  CONCLUSIONS
  From the morphological aspect, Er:YAG laser has much more advantage than ultrasonic instrument and diamond bur for the root resection.
authors.affiliation: Dept. of General Therapy, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Xiao-yi
authors.initials: XY
authors.lastname: Zhao
authors.forename: Shi-ming
authors.initials: SM
authors.lastname: Wang
authors.forename: Cheng-fei
authors.initials: CF
authors.lastname: Zhang
mesh_terms: D003804:Dentin; D007180:Incisor; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D016369:Smear Layer