title: Characteristics of the molar surface after removal of cervical enamel projections: comparison of three different rotating instruments.
abstract: OBJECTIVE
  The aim of this study was to evaluate and compare tooth surface characteristics in extracted human molars after cervical enamel projections (CEPs) were removed with the use of three rotating instruments.
  
  
  METHODS
  We classified 60 extracted molars due to periodontal lesion with CEPs into grade I, II, or III, according to the Masters and Hoskins' criteria. Each group contained 20 specimens. Three rotating instruments were used to remove the CEPs: a piezoelectric ultrasonic scaler, a periodontal bur, and a diamond bur. Tooth surface characteristics before and after removal of the projections were then evaluated with scanning electron microscopy (SEM). We analyzed the characteristics of the tooth surfaces with respect to roughness and whether the enamel projections had been completely removed.
  
  
  RESULTS
  In SEM images, surfaces treated with the diamond bur were smoothest, but this instrument caused considerable harm to tooth structures near the CEPs. The piezoelectric ultrasonic scaler group produced the roughest surface but caused less harm to the tooth structure near the furcation. In general, the surfaces treated with the periodontal bur were smoother than those treated with the ultrasonic scaler, and the periodontal bur did not invade adjacent tooth structures.
  
  
  CONCLUSIONS
  For removal of grade II CEPs, the most effective instrument was the diamond bur. However, in removing grade III projections, the diamond bur can destroy both adjacent tooth structures and the periodontal apparatus. In such cases, careful use of the periodontal bur may be an appropriate substitute.
authors.affiliation: Department of Periodontology, Wonkwang University Daejeon Dental Hospital, Wonkwang University School of Dentistry, Daejeon, Korea .
authors.forename: Min-Jeong
authors.identifier: 0000-0003-2946-5621
authors.initials: MJ
authors.lastname: Ko
authors.affiliation: Department of Periodontology, Wonkwang University Daejeon Dental Hospital, Wonkwang University School of Dentistry, Daejeon, Korea .
authors.forename: Chan-Myung
authors.identifier: 0000-0002-8653-5844
authors.initials: CM
authors.lastname: Cho
authors.affiliation: Department of Periodontology, Wonkwang University Daejeon Dental Hospital, Wonkwang University School of Dentistry, Daejeon, Korea .
authors.forename: Seong-Nyum
authors.identifier: 0000-0003-4890-989X
authors.initials: SN
authors.lastname: Jeong
keywords: Dental enamel; Electron microscopic topography; Furcation defects; Root planing