Cleghorn Blaine M, Christie William H, Dong Cecilia C S
Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, Canada.
J Endod. 2007 May;33(5):509-16. doi: 10.1016/j.joen.2006.12.004. Epub 2007 Feb 27.
The purpose of this study was to undertake a comprehensive literature review of the root and root canal morphology of the mandibular first premolar. Published studies citing the anatomy and morphology of mandibular premolars report data for over 6,700 teeth. These studies were divided into anatomical studies reporting number of roots, number of canals, and apical morphology. Variations because of sex and ethnic background have also been reported, along with case reports of anomalies. Approximately 98% of the teeth in these studies were single-rooted. The incidence of two roots was 1.8%. Three roots when reported were found in 0.2% of the teeth studied. Four roots were rare and were found in less than 0.1% of the teeth studied. Studies of the internal canal morphology revealed that a single canal was present in 75.8% of the teeth. Two or more canals were found in 24.2% of the teeth studied. A single apical foramen was found in 78.9% of the teeth, whereas 21.1% had two or more apical foramina. The role of genetics and racial variation may result in differences of incidence of root number and canal number in human populations. The dental literature is not unique in studying ethnicity and sex variations. Higher incidences of teeth with additional canals and roots have been reported in Chinese, Australian, and sub-Sahara African populations. Physical anthropology studies seem to show the lowest incidence in Western Eurasian, Japanese and American Arctic populations. The root and root canal morphology of this tooth can be complex and requires careful evaluation prior to root canal therapy.
本研究的目的是对下颌第一前磨牙的牙根及根管形态进行全面的文献综述。引用下颌前磨牙解剖学和形态学的已发表研究报告了超过6700颗牙齿的数据。这些研究分为报告牙根数量、根管数量和根尖形态的解剖学研究。还报告了因性别和种族背景导致的变异，以及异常情况的病例报告。在这些研究中，约98%的牙齿为单根。双根的发生率为1.8%。报告的三根情况在0.2%的研究牙齿中发现。四根罕见，在不到0.1%的研究牙齿中发现。对根管内部形态的研究表明，75.8%的牙齿存在单根管。在24.2%的研究牙齿中发现了两根或更多根管。78.9%的牙齿发现有单个根尖孔，而21.1%的牙齿有两个或更多根尖孔。遗传和种族变异的作用可能导致人群中牙根数量和根管数量发生率的差异。牙科文献在研究种族和性别差异方面并非独一无二。在中国、澳大利亚和撒哈拉以南非洲人群中，报告的额外根管和牙根牙齿的发生率较高。体质人类学研究似乎显示在西欧亚、日本和美国北极人群中发生率最低。该牙齿的牙根及根管形态可能很复杂，在根管治疗前需要仔细评估。
