Gibson K R, Calcagno J M
Department of Anatomical Sciences, University of Texas Dental Branch, Houston 77225.
Am J Phys Anthropol. 1993 Aug;91(4):517-21. doi: 10.1002/ajpa.1330910408.
Impacted third molars affect 15%-20% of modern Americans and Western Europeans. In contrast, third molar impactions have not been reported in the early hominid fossil record. It is uncertain whether the lack of reports reflects an absence of impactions or a failure to recognize them. This communication is intended to raise awareness of the possibility of impactions by describing the appearance of impacted teeth and by noting two possible instances of impaction in early hominids. Specifically, the mandibular third molars of the Sterkfontein specimen, STS52b (Australopithecus africanus), and the left maxillary third molar of the Lake Turkana specimen, KNM-WT 17400 (Australopithecus boisei), are positioned in a manner which suggests that they would not have erupted normally. Both specimens also exhibit strong crowding of the anterior dentition, providing further support for the view that these individuals lacked sufficient space for normal eruption of the third molars. Other published reports of dental crowding in the hominid fossil record are noted, and it is suggested that more attention be paid to dental impaction and dental crowding in hominid evolution.
阻生第三磨牙影响着15% - 20%的现代美国人和西欧人。相比之下，早期人类化石记录中尚未有第三磨牙阻生的报道。目前尚不确定缺乏相关报道是因为不存在阻生情况，还是由于未能识别出阻生。本通讯旨在通过描述阻生牙的外观以及指出早期人类中可能存在的两例阻生情况，来提高人们对阻生可能性的认识。具体而言，斯泰克方丹标本STS52b（南方古猿非洲种）的下颌第三磨牙以及图尔卡纳湖标本KNM - WT 17400（鲍氏南方古猿）的左上颌第三磨牙，其位置表明它们无法正常萌出。这两个标本的前牙列也都表现出严重拥挤，进一步支持了这些个体没有足够空间让第三磨牙正常萌出的观点。文中还提及了人类化石记录中其他已发表的牙齿拥挤报告，并建议在人类进化研究中更多地关注牙齿阻生和牙齿拥挤问题。
