Kewalramani Radhika, Murthy Chethana S, Gupta Ravi
General Dentist, Dubai, UAE.
Department of Conservative Dentistry and Endodontics, Vokkaligara Sangha Dental College, Bangalore, India.
J Oral Biol Craniofac Res. 2019 Oct-Dec;9(4):347-351. doi: 10.1016/j.jobcr.2019.08.001. Epub 2019 Aug 31.
Elusive second mesiobuccal canal (MB2) in maxillary first molar are often missed during endodontic therapy and are a major cause of treatment failures. Its prevalence is known to vary among different populations and there is limited information on its prevalence in Indian population.
This study investigated the prevalence and location of second mesiobuccal (MB2) canal in mesiobuccal root of maxillary first molar using cone beam computed tomography (CBCT) images in an Indian population.
CBCT images of 598 three rooted maxillary first molars were studied. In each CBCT image, the floor of pulp chamber was located and advanced by 2 mm to standardize the observation for MB2 canal. Its location was determined in relation to mesiobuccal (MB1) and palatal (P) canal.
The data was analysed using descriptive statistics. The presence of MB2 canal was correlated with age, gender and tooth position using Chi square test.
The prevalence of MB2 canal in three rooted maxillary first molar was 61.9%. It was seen that the prevalence of MB2 was highest in 20-40years age group (67.4%) followed by > 40 years (57.5%) and lowest in <20 years (50.6%) and the difference was statistically significant (p = 0.005). It is located mesiopalatally; 2.5 mm ± 0.6 mm palatally and 1.0 ± 0.4mmmesially to the MB1 canal or present directly on the line joining the MB1 and palatal canal.
There is a high probability of finding MB2 canal in Indian patients. The access cavity must be modified from a triangular shape to rhomboid shape. Troughingmesiopaltally (about 2.5 mm palatally and 1 mm mesially) from MB1 to a depth of about 2 mm from the floor of pulp chamber may be necessary for locating MB2 canal.
上颌第一磨牙中难以捉摸的近中颊侧第二根管（MB2）在根管治疗过程中常常被遗漏，并且是治疗失败的主要原因。已知其患病率在不同人群中有所差异，而关于印度人群中其患病率的信息有限。
本研究使用锥形束计算机断层扫描（CBCT）图像，调查印度人群上颌第一磨牙近中颊根中近中颊侧第二根管（MB2）的患病率及位置。
研究了598颗三根上颌第一磨牙的CBCT图像。在每张CBCT图像中，确定髓腔底部位置并向根尖方向推进2毫米，以标准化对MB2根管的观察。根据近中颊侧（MB1）和腭侧（P）根管确定其位置。
使用描述性统计分析数据。采用卡方检验分析MB2根管的存在与年龄、性别和牙位的相关性。
三根上颌第一磨牙中MB2根管的患病率为61.9%。可见MB2患病率在20 - 40岁年龄组最高（67.4%），其次是>40岁组（57.5%），<20岁组最低（50.6%），差异具有统计学意义（p = 0.005）。它位于近中腭侧；相对于MB1根管，在腭侧2.5毫米±0.6毫米且近中1.0±0.4毫米处，或直接位于连接MB1和腭侧根管的连线上。
在印度患者中发现MB2根管的可能性很高。进入腔必须从三角形改为菱形。从MB1向近中腭侧（约腭侧2.5毫米和近中1毫米）开槽至距髓腔底部约2毫米的深度，可能有助于定位MB2根管。
