School of Dentistry, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan.
Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Orthopaedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.
J Endod. 2018 Oct;44(10):1492-1499.e1. doi: 10.1016/j.joen.2018.05.016. Epub 2018 Aug 23.
The aim of this study was to determine the prevalence of C-shaped canal configurations (CSs) and radicular grooves (RGs) in permanent mandibular first premolars (MPs) and to investigate the relevance of such complexities with the presence of distolingual roots (DLRs) in permanent mandibular first molars (MMs).
A total of 800 pairs of MPs and MMs were investigated using a cone-beam computed tomographic system (NewTom 5G; QR srl, Verona, Italy). The frequency and symmetry of DLRs in MMs along with the occurrence of RGs and CSs in examined MPs were evaluated. Multivariable logistic regression analysis was applied to examine the correlation between the CSs of MPs with the appearance of DLRs in MMs.
In the examined teeth, 23.0% of MMs had a DLR, whereas 16.6% of MPs had RGs and 12.5% of MPs had C-shaped canals. Although the most common canal configuration in MPs is the single canal (74.1%), the other 25.9% still possess complicated root canals. Of these MPs that have different canal configurations, 54.6% had 2 canals, whereas 44.4% had CSs. Specifically, the CS showed a high prevalence of C3 morphologies at 98.9% followed by C1 at 1.1%. A corresponding and increasing frequency was noted in CSs and RGs of MPs and MMs with DLRs (P < .001). After adjusting for related categoric variables, the adjusted odds ratios for CSs of MPs in the bilateral DLR group compared with the non-DLR group was 3.294 (P < .001).
This study showed an increased appearance of CSs in MPs when DLRs were present in MMs in the Taiwanese population.
本研究旨在确定恒磨牙第一磨牙（MMs）远中舌侧根（DLRs）存在情况下，下颌第一前磨牙（MPs）中 C 型根管（CSs）和根管侧支（RGs）的发生率，并探讨这些复杂性与 DLRs 存在的相关性。
使用锥形束 CT 系统（NewTom 5G；QR srl，维罗纳，意大利）对 800 对 MPs 和 MMs 进行了检查。评估了 MMs 中 DLRs 的频率和对称性以及检查的 MPs 中 RGs 和 CSs 的发生情况。应用多变量逻辑回归分析来检查 MPs 中 CSs 与 MMs 中 DLRs 出现的相关性。
在所检查的牙齿中，23.0%的 MMs 有 DLR，而 16.6%的 MPs 有 RGs，12.5%的 MPs 有 C 型根管。尽管 MPs 中最常见的根管形态是单根管（74.1%），但仍有 25.9%的 MPs 具有复杂的根管。在具有不同根管形态的 MPs 中，54.6%有 2 个根管，而 44.4%有 CSs。具体来说，CSs 以 98.9%的 C3 形态为主，1.1%为 C1。在 MMs 和 MPs 中，随着 DLRs 的出现，CSs 和 RGs 的出现频率也相应增加（P<.001）。在调整了相关分类变量后，双侧 DLR 组与非 DLR 组相比，MPs 中 CSs 的调整比值比为 3.294（P<.001）。
本研究表明，在台湾人群中，当 MMs 中存在 DLRs 时，MPs 中 CSs 的出现频率增加。
