Rahimi Saeed, Mokhtari Hadi, Ranjkesh Bahram, Johari Masoomeh, Frough Reyhani Mohammad, Shahi Shahriar, Seif Reyhani Sina
Dental and Periodontal Research Center, Department of Endodontics, Dental School, Tabriz University of Medical Sciences, Tabriz, Iran.
Department of Dentistry and Oral Health, Aarhus University, Health, Denmark Section of Dental Pathology, Operative Dentistry and Endodontics, Vannelyst boulevard, Aarhus, Denmark.
Iran Endod J. 2017 Winter;12(1):70-73. doi: 10.22037/iej.2017.14.
Having knowledge about the anatomy of root canal system is essential for success of endodontic treatment. The present study used cone-beam computed tomography (CBCT), to evaluate the prevalence of third root in mandibular first molars in a selected Iranian population.
A total of 386 CBCT images from subjects referred to oral and maxillofacial radiology department of dental faculty of Tabriz University of Medical Sciences from 2011 to 2013 were selected and evaluated for this study and the cases with well-developed permanent mandibular first molars were included. The 3D images were reconstructed in axial cross sections and evaluated by two endodontists for the presence of the third extra lingual (radix entomolaris) or buccal (radix paramolaris) root. The chi-squared test was used to evaluate the relationship between gender and bilateral incidence of extra roots in mandibular first molars.
The distribution of three-rooted mandibular first molars with an additional root was 3%, (3.53% in female and 2.50% in male patients). There was no significant relationship between gender and bilateral occurrence of three-rooted mandibular first molars.
The occurrence of three-rooted mandibular first molars in Iranian population is not uncommon which should be taken into consideration by the dental practitioners during root canal treatment of these teeth.
了解根管系统的解剖结构是牙髓治疗成功的关键。本研究采用锥形束计算机断层扫描（CBCT），评估特定伊朗人群下颌第一磨牙中第三根的发生率。
选取2011年至2013年转诊至大不里士医科大学牙科学院口腔颌面放射科的受试者的386张CBCT图像进行本研究评估，纳入恒牙下颌第一磨牙发育良好的病例。将三维图像重建为轴向横截面，由两名牙髓病医生评估是否存在第三根额外的舌侧根（远中根）或颊侧根（副根）。采用卡方检验评估性别与下颌第一磨牙额外根双侧发生率之间的关系。
有额外根的三根下颌第一磨牙的分布率为3%（女性患者为3.53%，男性患者为2.50%）。性别与三根下颌第一磨牙的双侧发生率之间无显著关系。
伊朗人群中三根下颌第一磨牙的发生率并不罕见，牙科医生在对这些牙齿进行根管治疗时应予以考虑。
