title: [The application of laser holograph-speckle interferometry for measuring rotation of abutment teeth].
abstract: OBJECTIVE
  To explore the rotation of abutment teeth of fixed partial denture in chewing and to analyze the effect of rotation on the stability of abutment teeth.
  
  
  METHODS
  Left mandible (without the second premolar and the first molar) was used for specimen. Holograph-speckle interferometry was employed for measuring the rotation angle.
  
  
  RESULTS
  The maximal rotation angle was no more than 0.6 degrees and change of the angle was obviously in nonlinearity, when load increased from 9.8 N to 225.4 N.
  
  
  CONCLUSIONS
  The laser holograph-speckle interferometry could be used to measure rotation of abutment teeth. The intricate surface contacting was the main reason for rotation and this rotation had no bad effect on abutment teeth of fixed partial denture in daily use.
authors.affiliation: Department of Stomatology, 2nd Affiliated Hospital, College of Medical Sciences, Zhejiang University, Hangzhou 310009, China. zyz85@hotmail.com
authors.forename: Yan-zhen
authors.initials: YZ
authors.lastname: Zhang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000044:Dental Abutments; D003830:Denture, Partial, Fixed; D006801:Humans; D007368:Interferometry / Q000379:methods*; D008297:Male; D012399:Rotation