英语语法分析

Aim To investigate the clinical incidence of the second mesiobuccal root canal of maxillary first molars.

目的研究上颌第一磨牙近中颊根第二根管的临床发现率。

Results Of the 24 maxillary first molars of 20 patients, 14 of the molars had second mesiobuccal root canals.

结果20例患者的24颗上颌第一磨牙中有14颗存在近中颊根第二根管，发现率为58。

Most of which happened in mesiobuccal canal of maxillary molar and mesial canal of mandibular molar, accounting for 70.7%.

器械折断于上磨牙近颊根管和下磨牙近中根管者居多，占70.7%。器械折断在根管中下段多见，占70%。