Chan Eugene, Darendeliler M Ali
Faculty of Dentistry, University of Sydney, Sydney Dental Hospital, South West Area Health Services, Australia.
Am J Orthod Dentofacial Orthop. 2006 Apr;129(4):504-10. doi: 10.1016/j.ajodo.2004.12.018.
The aim of this article was to quantify the extent of root resorption in areas of compression or tension under light and heavy buccal tipping orthodontic forces.
The sample consisted of 36 premolars in 16 patients. On 1 side, light (25 g) or heavy (225 g) buccal tipping orthodontic forces were activated for 28 days. The contralateral side in each patient served as the control (0 g). The teeth were extracted, disinfected, imaged under a scanning electron microscope, and analyzed with commercial stereo imaging computer software modified for this study. Buccal and lingual surfaces were divided into 3 equal regions: cervical, middle, and apical. The root surface areas of these regions were documented with straight-on images. Quantification of resorption craters by using volumetric analysis was performed from stereo images taken at +/-3 degrees. The degree of resorption was correlated to the amount of surface area under compression or tension.
The buccal cervical region had 8.16-fold more root resorption in the heavy-force group compared with the light-force group (P <.01). The other regions did not seem to have significant differences in the force levels. In the experimental teeth, there was more root resorption in the high-compression regions than in the other regions (P <.01). There were similar amounts of resorption per unit area on the lingual apical and buccal cervical regions. Regions under compression had more root resorption than regions under tension. There was more resorption in regions under heavy compression than in regions under light compression (P <.01). There was also more root resorption in regions under heavy tension than in regions under light tension (P <.01).
本文旨在量化在轻力和重力颊向倾斜正畸力作用下，受压或受拉区域牙根吸收的程度。
样本包括16例患者的36颗前磨牙。在一侧，激活轻力（25克）或重力（225克）颊向倾斜正畸力28天。每位患者的对侧作为对照（0克）。拔牙后进行消毒，在扫描电子显微镜下成像，并使用为此研究修改的商业立体成像计算机软件进行分析。颊侧和舌侧表面分为3个相等区域：颈部、中部和根尖部。这些区域的牙根表面积通过直视图像记录。使用体积分析从±3度拍摄的立体图像中对吸收坑进行量化。吸收程度与受压或受拉的表面积相关。
重力组颊侧颈部区域的牙根吸收比轻力组多8.16倍（P<.01）。其他区域在力的水平上似乎没有显著差异。在实验牙中，高压缩区域的牙根吸收比其他区域更多（P<.01）。舌侧根尖部和颊侧颈部区域每单位面积的吸收量相似。受压区域的牙根吸收比受拉区域更多。重压缩区域的吸收比轻压缩区域更多（P<.01）。重拉力区域的牙根吸收也比轻拉力区域更多（P<.01）。
