Wang Dandan, Wang Ru, Xu Hongyan, Zhang Qianqian, Guo Yali
Department of Endodontics, Shaanxi Provincial People's Hospital, Xi'an, China.
BMC Oral Health. 2025 Jan 28;25(1):147. doi: 10.1186/s12903-025-05533-1.
This study aims to investigate the prevalence and morphology of middle mesial canal (MMC) in mandibular first molar (M1M) among a Northwestern Chinese population, and to analyze their relationship with anatomical aspects of the mesial root.
Cone beam computed tomography (CBCT) was utilized to evaluate 898 M1Ms and assess the incidence and morphology of MMC. The following parameters for M1M with or without MMC were obtained: the vertical distance between the first appearance of MMC and canal orifices (D), the distance between mesiobuccal (MB) and mesiolingual (ML) canals (D1), the buccolingual width(L1) and mesiodistal width (L2) of mesial roots, and the flatness degree(L1/L2) of mesial roots. The results were statistically analyzed.
The prevalence of MMC was 9.6% when considering the number of teeth and 7.2% when considering individuals. The presence of MMC was not significantly associated with sex (p = 0.993) or age (p = 0.211). Type 1-3-2 emerged as the most prevalent root canal morphology. MMC primarily manifested within 4 mm below the canal orifices. In cases where MMC was present, the MB-ML distance was significantly greater (p = 0.017). Conversely, no significant correlation was found between the presence of MMC and the length, width, or flatness degree of the mesial roots.
The morphology of MMCs is complex, and most of them exhibit confluent canals. In instances where MMCs are present, the MB-ML distance is significantly larger. For effective detection of MMC, a thorough examination of the area within 4 mm beneath the canal orifice is recommended.
本研究旨在调查中国西北人群下颌第一磨牙（M1M）中近中中根管（MMC）的发生率及形态，并分析其与近中根解剖学特征的关系。
采用锥形束计算机断层扫描（CBCT）评估898颗M1M，以评估MMC的发生率和形态。获取有或无MMC的M1M的以下参数：MMC首次出现处与根管口之间的垂直距离（D）、近中颊（MB）和近中舌（ML）根管之间的距离（D1）、近中根的颊舌宽度（L1）和近远中宽度（L2），以及近中根的扁平度（L1/L2）。对结果进行统计学分析。
以牙齿数量计算时，MMC的发生率为9.6%；以个体计算时，发生率为7.2%。MMC的存在与性别（p = 0.993）或年龄（p = 0.211）无显著相关性。1-3-2型是最常见的根管形态。MMC主要出现在根管口下方4mm范围内。存在MMC的情况下，MB-ML距离显著更大（p = 0.017）。相反，MMC的存在与近中根的长度、宽度或扁平度之间未发现显著相关性。
MMC的形态复杂，大多数表现为融合根管。存在MMC的情况下，MB-ML距离显著更大。为有效检测MMC，建议对根管口下方4mm范围内的区域进行全面检查。
