title: [Evaluation of the cavity cleaning of ultrasonic instruments and slow-speed handpiece in posterior teeth root-end preparation].
abstract: OBJECTIVE
  To compare the cleanliness of root end preparations by using ultrasonic instrumentation and slow-speed handpiece.
  
  
  METHODS
  Thirty-two mesial roots of the first mandibular molars with two canals and mature root apices were assigned randomly to 2 groups, each group had 16 teeth. The root-end preparations were made respectively using ultrasonic diamond tip Berutti and NiTi tip RE2 and slow-speed handpiece with No.2 round bur. Root end cavities were examined under scanning electron microscope for further evaluation of the superficial debris and smear layer of the root end preparations. SPSS 13.0 software package was used for Kruskal Wallis test.
  
  
  RESULTS
  Ultrasonic preparation had significantly less superficial debris and smear layer than slow-speed handpiece preparation (P<0.05).
  
  
  CONCLUSIONS
  Ultrasonic instrument creates cleaner surfaces for root end cavities than slow-speed handpiece preparation in posterior teeth root end preparation.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Guangxi Medical University, Guangxi Province, China. zhangpingjuan123123@126.com
authors.forename: Ping-juan
authors.initials: PJ
authors.lastname: Zhang
authors.forename: Wen-xia
authors.initials: WX
authors.lastname: Chen
authors.forename: Qi-xin
authors.initials: QX
authors.lastname: Zeng
authors.forename: Fang-fang
authors.initials: FF
authors.lastname: Xie
mesh_terms: D003731:Dental Caries; D006801:Humans; D008963:Molar; D018915:Root Canal Preparation; D016369:Smear Layer; D014465:Ultrasonics