title: The effect of the angle of instrumentation of the Piezoelectric Ultrasonic Scaler on root surfaces.
abstract: OBJECTIVE
  To evaluate the influence of variations in the working angle of the piezoelectric ultrasonic scaler (PUS) on root surfaces.
  
  
  METHODS
  Fifty-five uniradicular bovine teeth were used, of which 25 teeth were used for the analysis of the roughness and root wear, while the remaining 30 teeth were used for the analysis of morphology (MRS) and the attachment of blood components (ABC). The teeth were randomly divided into five groups according to the type of treatment (G1-G5: piezoelectric ultrasonic scaler; G6: manual curette) and to the PUS working angle applied (G1: 0°; G2: 30°; G3: 45°; G4: 60°; G5: 90°). For statistical analysis, the data describing the MRS and ABC were analysed by the Kruskal-Wallis and Dunn's tests, and the data describing the roughness and tooth wear were analysed by anova and Tukey's tests at the significance level of 5%.
  
  
  RESULTS
  Manual curette (MC) promoted a smoother root surface than the application of the PUS. The PUS used at the angles of 30° and 45° resulted in a high level of ABC that was comparable to that obtained by MC. Additionally, the group in which the PUS was applied at an angle of 45° exhibited less tooth wear than the other groups.
  
  
  CONCLUSIONS
  Changes in the working angle of the PUS influenced the characteristics of root surfaces after instrumentation.
authors.affiliation: Foar-UNESP, School of Dentistry of Araraquara, São Paulo State University, Araraquara, Brazil.
authors.forename: Gjpl
authors.initials: G
authors.lastname: Oliveira
authors.affiliation: Foar-UNESP, School of Dentistry of Araraquara, São Paulo State University, Araraquara, Brazil.
authors.forename: P D
authors.initials: PD
authors.lastname: Macedo
authors.affiliation: Foar-UNESP, School of Dentistry of Araraquara, São Paulo State University, Araraquara, Brazil.
authors.forename: J N
authors.initials: JN
authors.lastname: Tsurumaki
authors.affiliation: Foar-UNESP, School of Dentistry of Araraquara, São Paulo State University, Araraquara, Brazil.
authors.forename: J E
authors.initials: JE
authors.lastname: Sampaio
authors.affiliation: Foar-UNESP, School of Dentistry of Araraquara, São Paulo State University, Araraquara, Brazil.
authors.forename: Rac
authors.initials: R
authors.lastname: Marcantonio
mesh_terms: D000818:Animals; D002417:Cattle; D003728:Dental Calculus / Q000628:therapy; D012534:Dental Scaling / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016745:Root Planing / Q000295:instrumentation* / Q000379:methods; D013499:Surface Properties; D014070:Tooth / Q000648:ultrastructure; D014092:Tooth Root / Q000648:ultrastructure*; D057085:Tooth Wear / Q000473:pathology; D014464:Ultrasonic Therapy / Q000295:instrumentation*; D014867:Water
chemical_list: D014867:Water
keywords: periodontitis; scanning electron microscopy; tooth wear; ultrasonics