骨性Ⅲ类错下前牙区牙槽骨形态的锥形束CT分析

Preliminary cone-beam computed tomography study of alveolar bone of anterior mandible in adults with skeletal Class Ⅲ malocclusion

目的:应用锥形束CT(cone-beam computed tomography,CBCT)评价骨性Ⅲ类和骨性Ⅰ类错患者下颌切牙区牙槽骨形态的差异。方法:选取45例恒牙期骨性Ⅲ类错病例及45例恒牙期骨性Ⅰ类错病例矫治前的CBCT图像,测量下切牙区的牙槽骨厚度,应用SPSS16.0软件包对测量结果进行团体t检验。结果:骨性Ⅲ类组唇侧、舌侧、唇舌侧总牙槽骨厚度平均值分别为2.0437mm、3.0750mm和5.1187mm,骨性Ⅰ类组唇侧、舌侧、唇舌侧总牙槽骨厚度平均值分别为2.6176mm、4.2765mm和7.0941mm。2组间唇侧、舌侧和唇舌侧总牙槽骨平均厚度均有显著差异(P<0.01)。结论:骨性Ⅲ类错患者的下前牙区牙槽骨存在菲薄的现象,提示在正畸治疗过程中,无论是内收下前牙还是去代偿正畸,均要警惕牙槽骨吸收和牙根暴露。

PURPOSE： To evaluate the thickness of alveolar bone of mandibular anterior teeth in adults with skeletal Class III malocclusion by a method of detailed cone-beam computed tomography（CBCT） images.METHODS： The subjects were 45 untreated patients with skeletal Class Ⅲ malocclusion and 45 untreated patients with skeletal Class I malocclusion.They were divided into 2 groups： skeletal Class Ⅲ and skeletal Class I patients.Tomography was carried out using KODAK9000C 3D volume scanner before orthodontic treatment.Three-dimensional CBCT software（Kodak dental imaging software 3D module v 2.4,Eastman Kodak Company,French） was used to measure the labial,lingual and total thickness of alveolar bone of mandibular anterior teeth by 6 reference points.The thicknesses of alveolar bone of both groups were measured along an axial plane at mandibular anterior teeth root apex levels from a CBCT image.Differences between the 2 groups were analyzed by using group t test with SPSS16.0 software package.RESULTS： The thickness of the alveolar bone of mandibular anterior teeth was greater in the skeletal Class I than the skeletal Class Ⅲ subjects.There was significant（P0.05） difference between the two groups.CONCLUSIONS： The thickness of alveolar bone of mandibular anterior segment was obviously thinner in the skeletal Class Ⅲ malocclusion than that in Class I.More attention was recommended to be paid in skeletal Class Ⅲ patient.