Kong Ling-jia, Wan Kuo, Liu Deng-gao
Chin Med Sci J. 2015 Sep;30(3):174-8. doi: 10.1016/s1001-9294(15)30043-2.
To evaluate the incidence of two-rooted mandibular premolar morphology using full-mouth periapical film series in a Chinese population, with particular emphasis on bilateral incidence, so as to provide a clinical anatomical basis for root canal treatment in mandibular premolars.
A total of 2015 patients who underwent dental treatment and had full mouth periapical radiographs at the Peking University School of Stomatology from April 2011 to April 2012 were enrolled in this study. Three experienced dentists reviewed the patients' periapical films and classified the root morphology of mandibular premolars bilaterally. The incidence of unilateral and bilateral double roots were recorded and calculated, including confirmed and suspected bucco-lingual root types.
In terms of the morphology of two-rooted mandibular first premolars, of the 2015 cases with complete root formation, two-rooted first premolars were detected in 120 cases, with a total number of 159 teeth. According to the number of teeth, the overall incidence of double roots was 4.03% (159/3972). In terms of the morphology of two-rooted mandibular second premolars, of the 2015 cases with complete root formation, two-rooted second premolars were detected in 24 cases, with a total number of 33 teeth. According to the number of teeth, the overall incidence of double roots was 0.85% (33/3880).
The roots of mandibular premolars display specific morphological patterns. Based on a large sample, we observed and calculated not only the occurrence rate of bucco-lingual and mesio-distal double roots in first and second mandibular premolars, but also the incidence of unilateral or bilateral double roots within the same mandible. These findings could provide useful information on the anatomical structure of mandibular premolars for endodontic, prosthodontic and surgical procedures, and could improve the quality of treatment and reduce complications.
利用全口根尖片评估中国人群中双根下颌前磨牙的形态发生率，尤其关注双侧发生率，为下颌前磨牙根管治疗提供临床解剖学依据。
选取2011年4月至2012年4月在北京大学口腔医学院接受牙科治疗并拍摄了全口根尖片的2015例患者。三名经验丰富的牙医对患者的根尖片进行评估，双侧分类下颌前磨牙的牙根形态。记录并计算单根和双根的发生率，包括确定的和疑似的颊舌根类型。
就双根下颌第一前磨牙的形态而言，在2015例牙根完全形成的病例中，检测到双根第一前磨牙120例，共159颗牙。按牙数计算，双根的总体发生率为4.03%（159/3972）。就双根下颌第二前磨牙的形态而言，在2015例牙根完全形成的病例中，检测到双根第二前磨牙24例，共33颗牙。按牙数计算，双根的总体发生率为0.85%（33/3880）。
下颌前磨牙的牙根呈现特定的形态模式。基于大样本，我们不仅观察并计算了下颌第一和第二前磨牙颊舌向和近远中向双根的发生率，还计算了同一下颌内单根或双根的发生率。这些发现可为牙髓病学、修复学和外科手术提供有关下颌前磨牙解剖结构的有用信息，并可提高治疗质量和减少并发症。
