上颌第二磨牙近颊融合根中MB2的锥束CT研究

Cone-beam CT Research of MB2 in Fused Mesiobuccal Root of Maxillary Second Molar

目的:通过锥束CT技术研究上颌第二磨牙近颊融合根中MB2的发生率。方法:收集199例患者的上颌第二磨牙CBCT数据,观察牙根融合类型、年龄以及牙位对MB2发生的影响。结果:199例患者共有380颗上颌第二磨牙,其中145颗牙的近中颊根与其他牙根融合;近远中颊根融合型(Ⅰ型)和近中颊根腭根融合型(Ⅱ型)的MB2发生率分别是5.5%、41.9%,而全融合型(Ⅲ型)则未发现MB2,Ⅰ、Ⅲ型融合的MB2发生率低于Ⅱ型;随着年龄增大,MB2发生率降低;181例具有双侧上颌第二磨牙的患者中,左右两侧融合根及MB2的发生率无显著差异。结论:上颌第二磨牙近中颊根与其他牙根融合时,其MB2发生率会出现变异。

Objective： To investigate the incidence of MB2 in fused mesiobuccal roots of maxillary second molars by cone-beam computed tomography （CBCT）. Methods： CBCT images of 199 patients were collected. The relation between MB2 incidence and root fusion type, age and teeth position was investigated. Results： Of 380 maxillary second molars from 199 patients, 145 teeth （38.1%） had fused mesiobuccal roots. The incidence of teeth with mesiobuccal root fused to distobuceal root （Type I） and palatal root （Type Ⅱ ） were 5.5o//oo and 41.90//oo respectively. No MB2 was detected in all roots fused teeth （Type Ill ）. The incidence of MB2 in Type I and Ill was significantly lower than in Type H and three separated roots. The incidence of MB2 decreased with age increasing. Of 181 patients with bilateral maxillary second molars, the incidence of fused roots and MB2 didn＇t correlate with the tooth position. Conclusion： The incidence of MB2 varied in teeth with fused mesiobuccal root in maxillary second molars.