Abstract:

Objective To evaluatethe detection rate, typing, and therapeutic effect of second mesiobuccal canals(MB2) of first molars under dental operating microscope.Methods 88 maxillary molars with the presence of MB2 through cone beam computed tomography (CBCT) were collected, in which 68 were received root canal treatment and 20 were received root canal retreatment because of the missing canal of MB2 respectively. The type of mesiobuccal root canal in the former 68 maxillary molars were analyzed under CBCT. The 68 maxillary molars were divided into 2 groups, with 34 in each group. The experienment group received treatment under dental operating microscope, while the control group under naked eyes. MB2 detection rate, treatment and retreatment effect between two groups were compared. The latter 20 maxillary molars were also seperated into 2 groups, in which 10 cases were treated under microscope and 10 cases were treated under naked eye. The effect of retreatment was observed.Results The type of mesiobuccal root canal in 68 maxillary molars under CBCT were mainlytypeⅡand typeⅢ, with the proportion of 77.9% (53 cases) and 22.1% (15 cases) respectively. The detection rate of MB2 in the experimental group was 100%, and 91.2% (30 cases) in the control group, a statistical difference can be found between 2 groups (P < 0.05). 97.5% (33 cases) of the experimental group was successfully treated, and 79.4% (27 cases) for the control group (P < 0.05). The success rate of retreatment under microscope was 60% (6 cases), which was significantly higher than that of the naked eye (P < 0.05). In 3-month and 6-month follow-up, the treatment effect in experimental group was significantly better than the control group (P < 0.05).Conclusion Dental microscope can help to increase MB2 detection rate and improve treatment and retreatment effect.

Key words: Microscope, MB2, Detection, Root canal treatment, Root canal retreatment

摘要：

目的 探讨显微镜对上颌第一磨牙近中颊根第二根管（second mesiobuccal canals,MB2）的定位探查,以及根管治疗的效果。方法 收集患者共88例88颗患牙,在牙科锥形束CT（cone beam computed tomography,CBCT）下确诊MB2存在并接受初次治疗68例,及MB2存在而未发现致根管治疗失败后需再治疗20例。68例患者在CBCT下进一步分析近中颊根根管分型,根据患者的意愿选择不同的治疗方法。试验组34例,显微镜下对MB2进行观察探查并治疗;对照组34例,未用显微镜直视下进行观察探查和治疗。比较2组MB2根管的检出及治疗效果。20例再治疗患者,10例于显微镜下进行再治疗,10例直视下接受常规治疗,比较2组再治疗的效果。结果 68颗患牙的CBCT检查结果近中颊根根管以Ⅱ型和Ⅲ型根管为主,其中Ⅱ型53例占77.9%,Ⅲ型15例占22.1%。试验组的MB2检出率为100%,对照组MB2检出率为91.2%,2组差异具有统计学意义（P < 0.05）。试验组根管治疗成功率为97.5%,明显高于对照组的79.4%（P < 0.05）。2组术后3个月及6个月后试验组疗效构成比明显优于对照组（P < 0.05）。显微镜下再治疗成功10例,直视下再治疗成功6例。根管再治疗患者术后3个月及6个月疗效构成比保持不变。结论 显微镜对上颌第一磨牙MB2根管的探查及治疗具有一定的临床价值。

关键词: 口腔显微镜, MB2, 探查, 根管治疗, 根管再治疗