安氏Ⅱ类不同前牙唇倾度牙根长度及牙槽骨形态分析

Analysis of the root length and alveolar bone of maxillary central incisors of different inclination of Angle classⅡ patients

目的应用CBCT对不同前牙唇倾度安氏Ⅱ类错[牙合]畸形牙根长度进行测量,对骨开窗发生情况进行计数,为临床治疗方案的确定和评估风险提供参考。方法选取90例未经正畸治疗的安氏Ⅱ类错牙合畸形患者,根据上颌中切牙的不同唇倾度分为唇倾组、直立组、舌倾组,利用CBCT及Invivo5.2软件进行三维重建,测量上颌中切牙牙根长度,计数其骨开窗情况,并进行统计学分析。结果唇倾组切牙牙根长度为(12.14±1.75)mm,舌倾组为(12.07±1.11)mm,直立组为(12.70±1.49)mm,差异无统计学意义(P>0.05)。安氏Ⅱ类舌倾组上颌中切牙唇侧骨开窗发生率[26.67%(8/30)]明显高于唇倾组[6.67%(2/30)]和直立组[3.33%(1/30)],差异有统计学意义(均P<0.05);唇倾组与直立组之间唇侧骨开窗发生率比较,差异无统计学意义(P>0.05)。结论正畸治疗前安氏Ⅱ类患者不同上前牙唇倾度上颌中切牙的牙根长度无差异,为正畸治疗和牙根吸收的关系提供了理论依据。舌倾的上前牙有较高的骨开窗发生率,临床矫治时注意转矩的控制及风险的评估。

Objective To measure the length of the tooth root of the Angle Ⅱ malocclusion of different anterior teeth with CBCT, and to count the occurrence of the bone fenestration and provide reference for the determination of the clinical treatment plan and the risk of the assessment. Methods Ninety cases of Angle Ⅱ malocclusion without orthodontic treatment were divided into three groups according to the different lip inclination of maxillary incisor, lip tilting group, orthostatic group and tongue tilting group. Three-dimensional reconstruction was carried out by CBCT and Invivo 5.2 software. The length of maxillary middle incisor root was measured and the bone window was counted and analyzed statistically. Results The root length of incisors was (12.14 ±1.75) mm in lip tilting group,(12.07 ±1.11) mm in orthostatic group, and (12.70 ±1.49) mm in upright group ( P > 0.05). The incidence of lip-side fenestration of maxillary middle incisor in Angle Ⅱ lingual inclination group [26.67%(8/30)] were significantly higher than that in lip tilting group [6.67%(2/30)] and orthostatic group [3.33%( 1/30 )], the differences were statistically significant (all P < 0.05). There was no significant difference in the incidence of lip bone fenestration between lip tilting group and orthostatic group ( P > 0.05). Conclusion Before orthodontic treatment, there is no difference in root length of upper middle incisor with different tipping of upper anterior teeth in Angle Ⅱ patients, which provides theoretical basis for the relationship between orthodontic treatment and root resorption. The upper anterior teeth with tilted tongue have a higher incidence of alveolar fenestration, and attention should be paid to torque control and risk assessment during clinical treatment.