Song Je Seon, Kim Seong-Oh, Choi Byung-Jai, Choi Hyung-Jun, Son Heung-Kyu, Lee Jae-Ho
Department of Pediatric Dentistry, Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009 Jan;107(1):e56-60. doi: 10.1016/j.tripleo.2008.09.004.
The mandibular first permanent and primary molars occasionally have an additional root located distolingually. This study aimed to determine the incidences of an additional root in these molars and their relationship.
This study involved 4050 children for whom periapical radiographs of the mandibular molar area were available. The incidence of an additional root for each molar was calculated and the pattern of concurrent additional roots in different molars was also investigated.
Additional roots were present in 33.1%, 27.8%, and 9.7% of the first permanent, second primary, and first primary molars, respectively. When an additional root was present in a primary molar, the probability of the posterior adjacent molar also having an additional root was greater than 94.3%.
The presence of an additional root in a primary molar can be used to predict the presence of an additional root in molars posterior to it.
下颌第一恒磨牙和第一乳磨牙偶尔会有一个位于远舌侧的额外牙根。本研究旨在确定这些磨牙中额外牙根的发生率及其关系。
本研究纳入了4050名有下颌磨牙区根尖片的儿童。计算每颗磨牙额外牙根的发生率，并研究不同磨牙同时出现额外牙根的模式。
额外牙根分别出现在33.1%的第一恒磨牙、27.8%的第二乳磨牙和9.7%的第一乳磨牙中。当一颗乳磨牙有额外牙根时，其后相邻磨牙也有额外牙根的概率大于94.3%。
乳磨牙中额外牙根的存在可用于预测其后方磨牙中额外牙根的存在。
