Department of Orthodontics, Applied Life Sciences, Hiroshima University Institute of Biomedical & Health Sciences, Japan and.
Eur J Orthod. 2013 Dec;35(6):790-5. doi: 10.1093/ejo/cjs100. Epub 2013 Jan 9.
The purpose of the present study was to clarify the prevalence and degree of root resorption induced by orthodontic treatment in patients with and without open bite. One hundred and eleven patients treated with multibracket appliances were retrospectively selected from the patients and divided into non-open bite (NOB) and open bite (OB) groups. The severity of root resorption and the root shape were classified into five groups on periapical radiographs before and after treatment. Moreover, only in the OB group, all teeth were sub-divided into functional and hypofunctional ones that are occluding and non-occluding. As the results of multiple linear regression analysis of patient characteristics and clinical variables with the number of overall root resorption, the independent variables that were found to contribute significantly to root resorption were bite and abnormal root shape. The prevalences of root resorption evaluated in the number of patients were significantly higher in OB group than in NOB group, and those in the number of teeth were significantly higher in OB group than in NOB group, in particular anterior and premolar teeth. The prevalence of resorbed teeth with abnormal root shapes was also significantly higher in OB group than in NOB group. On the other hand, in OB group, the prevalences of root resorption and teeth with abnormal root shape were significantly greater in hypofunctional teeth than in normal functional teeth. There are more teeth with root resorption and abnormal root shape in open bite cases than in normal bite cases, and more teeth with abnormal root shapes and root resorption in hypofunctional teeth than in functional teeth.
本研究旨在阐明伴有和不伴有开颌的正畸治疗患者的牙根吸收的发生率和程度。从患者中回顾性选择了 111 名接受多托槽矫治器治疗的患者，并将其分为非开颌（NOB）和开颌（OB）组。在治疗前后的根尖片上，将牙根吸收的严重程度和牙根形状分为五组。此外，仅在 OB 组中，所有牙齿均分为功能性和低功能的，即咬合和非咬合。在对患者特征和临床变量与总根吸收数量的多元线性回归分析中，发现对牙根吸收有显著贡献的独立变量是咬合和异常牙根形状。在患者数量上评估的牙根吸收发生率在 OB 组明显高于 NOB 组，在牙齿数量上 OB 组明显高于 NOB 组，尤其是在前牙和前磨牙。OB 组异常牙根形状的吸收牙的发生率也明显高于 NOB 组。另一方面，在 OB 组中，低功能牙齿的牙根吸收和异常牙根形状的发生率明显高于正常功能牙齿。与正常咬合病例相比，开颌病例中牙根吸收和异常牙根形状的牙齿更多，低功能牙齿中异常牙根形状和牙根吸收的牙齿更多。
