title: Use of a simple intraoral instrument to standardize film alignment and improve image reproducibility.
abstract: OBJECTIVE
  A lot of instruments and devices were reported in standardized realignment of intraoral film. However, these instruments either are too cumbersome and time consuming to be used or require extensive fabrication. In this study we described a prototype of a instrument for realignment of intraoral film and evalated its reproducibility.
  
  
  METHODS
  A technique that uses this instrument was compared with a validated method serving as control. An adult human dry skull with full dentition was exposed for measuring the angular errors. Two types of angular errors were calculated.
  
  
  RESULTS
  of the analysis of the alignment error caused by projection of the x-ray beam showed the mean horizontal angulation error (+/-SD) was 1.70 +/- 0.75 degrees and the vertical one was 1.32 +/- 0.44 degrees in the new instrument group, and 1.65 +/- 0.70 degrees and 1.40 +/- 0.61 degrees, respectively, in the control group. Bite block seating error was 2.12 +/- 0.55 degrees in the newly developed instrument and 2.01 +/- 0.49 degrees in the instrument with registration material. Statistical analysis showed no significant difference in the 2 instruments (P > .05).
  
  
  CONCLUSIONS
  The prototype of the new instrument reported by the authors can produce almost identical radiographs in vitro with only slight angular errors. Clinical use of the advanced type of the instrument can be expected to show similar results.
authors.affiliation: Department of Orthodontics, School of Dentistry, Zhejiang University, Hang Zhou, People's Republic of China. wujianchao555@yahoo.com.cn
authors.forename: Jian-Chao
authors.initials: JC
authors.lastname: Wu
authors.forename: Ji-Na
authors.initials: JN
authors.lastname: Huang
authors.forename: Shi-Fang
authors.initials: SF
authors.lastname: Zhao
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Xu
authors.forename: Jun-Chao
authors.initials: JC
authors.lastname: Zhang
authors.forename: Bing
authors.initials: B
authors.lastname: Xia
authors.forename: Yue-Fang
authors.initials: YF
authors.lastname: Dong
mesh_terms: D000328:Adult; D006801:Humans; D011861:Radiography, Dental / Q000295:instrumentation*; D015203:Reproducibility of Results; D014962:X-Ray Film