The effect of mandibular position on measurement in spiral tomography

나선형 단층방사선사진촬영에서 하악골 위치가 측정치에 미치는 영향

  • Jung Yun-Hoa (Department of Oral and Maxillofacial Radiology, College of Dentistry, Pusun National University)
  • 정연화 (부산대학교 치과대학 구강악안면방사선학교실)
  • Published : 2005.06.01

Abstract

Purpose : To evaluate the effect of deviation of mandibular positioning, by changing the mandibular plane inclination, on the measured height and width of mandible in spiral conventional tomography. Materials and Methods : By means of the Scanora multifunctional unit, cross-sectional tomograms were taken from two human dried mandibles at the mandibular angulations: -15 degree, -10 degree, -5 degree, and 0 degree. Twenty-eight sites in two dried mandibles were imaged. One examiner measured the bone heights and widths at selected sites on the images and the actual bone heights were recorded. Results : The bone heights at the four mandibular inclinations overestimated real bone heights and the mean difference between actual heights and image heights on 0 degrees was the smallest (P<0.01). The bone widths on -15 degrees were narrowest and there were significant differences between bone widths measured at the four mandibular inclinations (P<0.001). We found statistically significant differences between both bone heights and widths as measured according to the mandibular plane angle for the posterior region (P<0.01). Conclusion : The use of different mandibular positioning may result in discrepancies in heights and widths when measured from the cross-sectional tomographic images. It is suggested that the mandibular positioning may play a significant role in the measurement of mandibular heights and widths.

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