Loh H S
Department of Oral and Maxillofacial Surgery, National University of Singapore.
Aust Dent J. 1990 Oct;35(5):434-7. doi: 10.1111/j.1834-7819.1990.tb05426.x.
Seven hundred and eighty-six patients of Singaporean Chinese origin requiring extractions of permanent mandibular molars were screened. Personal details, identification of the tooth and the presence or absence of an extra root were recorded. Thirty-two cases (4.1 per cent) exhibited an extra disto-lingual root. None was found in the second molar. The first molar was affected (7.9 per cent) slightly more than twice as often as the third molar (3.7 per cent). The extra root was present almost equally in both sexes with a higher presentation on the left side. Six cases had a fracture of the extra root. A comparison was made with a study done by Tratman' on the same population and with other studies involving those of Chinese and Mongoloid origin in other countries.
对786名需要拔除下颌恒磨牙的华裔新加坡人进行了筛查。记录了个人详细信息、牙齿标识以及是否存在额外牙根。32例（4.1%）出现额外的远舌侧牙根。第二磨牙未发现此类情况。第一磨牙受影响的比例（7.9%）是第三磨牙（3.7%）的两倍多一点。额外牙根在男女中出现的比例几乎相同，且左侧出现的比例更高。6例出现额外牙根骨折。将该研究结果与特拉特曼对同一人群的研究以及其他涉及其他国家华裔和蒙古人种的研究进行了比较。
