OBJECTIVES: Distolingual root of the permanent mandibular first molar (PMFM-DLR) has been frequently reported, which may complicate the treatment of periodontitis. This study aimed to assess the morphological features of PMFM-DLR and investigate the correlation between the morphological features of PMFM-DLR and periodontal status in patients with Eastern Chinese ethnic background. MATERIALS AND METHODS: A total of 836 cone beam computed tomography (CBCT) images with 1497 mandibular first molars were analyzed to observe the prevalence of PMFM-DLR at the patients and tooth levels in Eastern China. Among them, complete periodontal charts were available for 69 Chinese patients with 103 teeth. Correlation and regression analyses were used to evaluate the correlation between the morphological features of DLR, bone loss, and periodontal clinical parameters, including clinical attachment loss (CAL), probing pocket depth (PPD), gingival recession (GR), and furcation involvement (FI). RESULTS: The patient-level prevalence and tooth-level prevalence of DLR in mandibular first molars were 29.4% and 26.3%, respectively. Multiple linear regression analysis suggested that bone loss at the lingual site and CAL were negatively affected by the angle of separation between distolingual and mesial roots in the transverse section, while they were significantly influenced by age and the angle of separation between distobuccal and mesial roots in the coronal section. CONCLUSIONS: The prevalence of PMFM-DLR in Eastern China was relatively high in our cohort. The morphological features of DLR were correlated with the periodontal status of mandibular first molars. This study provides critical information on the morphological features of DLR for improved diagnosis and treatment options of mandibular molars with DLR.
下颌第一磨牙远舌根已经被广泛报道，它的存在使牙周炎的治疗更为复杂。本研究旨在评估中国东部地区人群中下颌第一磨牙远舌根的发生率，并探讨远舌根的形态学特征与骨破坏及牙周状况的关联性。本研究通过对中国东部地区836例患者共1497颗下颌第一磨牙的锥形射束电脑断层扫描（CBCT）进行流行病学分析。其中，69例患者的103颗下颌第一磨牙有完整的牙周检查表。随后采用相关分析和回归分析评估下颌第一磨牙远舌根的形态学特征与骨缺损及牙周临床参数间的关系，包括临床附着缺失、探诊深度、牙龈退缩和根分叉病变情况。研究结果发现，中国东部地区人群中下颌第一磨牙远舌根在患者和牙位水平的患病率分别为29.4%和26.3%。多元线性回归分析表明，第一磨牙舌侧的骨缺损及临床附着丧失水平与位于横截面的远舌根与近中根的分离角呈负相关，而与年龄和位于冠状面上的远颊根与近中根的分离角呈正相关。综上，中国东部地区人群下颌第一磨牙远舌根患病率较高，而且下颌第一磨牙远舌根的形态特征与牙周状况具有相关性。本研究旨在提高下颌第一磨牙远舌根的早期诊断率，并对存在远舌根的第一磨牙的治疗决策提供重要的信息。.
下颌第一磨牙远舌根已经被广泛报道，它的存在使牙周炎的治疗更为复杂。本研究旨在评估中国东部地区人群中下颌第一磨牙远舌根的发生率，并探讨远舌根的形态学特征与骨破坏及牙周状况的关联性。本研究通过对中国东部地区836例患者共1497颗下颌第一磨牙的锥形射束电脑断层扫描（CBCT）进行流行病学分析。其中，69例患者的103颗下颌第一磨牙有完整的牙周检查表。随后采用相关分析和回归分析评估下颌第一磨牙远舌根的形态学特征与骨缺损及牙周临床参数间的关系，包括临床附着缺失、探诊深度、牙龈退缩和根分叉病变情况。研究结果发现，中国东部地区人群中下颌第一磨牙远舌根在患者和牙位水平的患病率分别为29.4%和26.3%。多元线性回归分析表明，第一磨牙舌侧的骨缺损及临床附着丧失水平与位于横截面的远舌根与近中根的分离角呈负相关，而与年龄和位于冠状面上的远颊根与近中根的分离角呈正相关。综上，中国东部地区人群下颌第一磨牙远舌根患病率较高，而且下颌第一磨牙远舌根的形态特征与牙周状况具有相关性。本研究旨在提高下颌第一磨牙远舌根的早期诊断率，并对存在远舌根的第一磨牙的治疗决策提供重要的信息。
Keywords: Clinical attachment loss; Cone beam computed tomography (CBCT); Distolingual root; Mandibular first molar; Periodontal clinical parameter.