上颌第二磨牙近颊融合根中MB2的锥束CT研究

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。

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

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 distobuccal root(Type Ⅰ) and palatal root(Type Ⅱ) were 5.5% and 41.9% respectively.No MB2 was detected in all roots fused teeth(Type Ⅲ).The incidence of MB2 in Type Ⅰ and Ⅲ was significantly lower than in Type Ⅱ 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.