Department of Pediatric Dentistry, Seoul National University Dental Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
Department of Pediatric Dentistry, Dental Research Institute, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
BMC Oral Health. 2023 Sep 8;23(1):650. doi: 10.1186/s12903-023-03349-5.
Permanent first molars with severe dental caries, developmental defects, or involved in oral pathologies are at risk of poor prognosis in children. Accordingly, using the third molar to replace the first molar can be a good treatment option when third molar agenesis is predicted early. Thus, this retrospective cohort study aimed to develop criteria for early detection of mandibular third molar (L8) agenesis based on the developmental stages of mandibular canine (L3), first premolar (L4), second premolar (L5), and second molar (L7).
Overall, 1,044 and 919 panoramic radiographs of 343 males and 317 females, respectively, taken between the ages of 6 and 12 years were included. All developmental stages of L3, L4, L5, L7, and L8 were analyzed based on the dental age, as suggested by Demirjian et al. The independent t-test was used to assess age differences between males and females. The rank correlation coefficients were examined using Kendall's tau with bootstrap analysis and Bonferroni's correction to confirm the teeth showing developmental stages most similar to those of L8s. Finally, a survival analysis was performed to determine the criteria for the early diagnosis of mandibular third molar agenesis.
Some age differences were found in dental developmental stages between males and females. Correlation coefficients between all stages of L3, L4, L5, and L7 and L8 were high. In particular, the correlation coefficient between L7 and L8 was the highest, whereas that between L3 and L8 was the lowest.
If at least two of the following criteria (F stage of L3, F stage of L4, F stage of L5, and E stage of L7) are met in the absence of L8 crypt, agenesis of L8 can be confirmed.
严重龋齿、发育缺陷或涉及口腔病理学的恒牙第一磨牙在儿童中预后不良。因此，当早期预测到第三磨牙缺失时，使用第三磨牙代替第一磨牙可能是一种很好的治疗选择。因此，本回顾性队列研究旨在根据下颌尖牙（L3）、第一前磨牙（L4）、第二前磨牙（L5）和第二磨牙（L7）的发育阶段，制定下颌第三磨牙（L8）缺失的早期检测标准。
共纳入 343 名男性和 317 名女性分别在 6 至 12 岁之间拍摄的 1044 张和 919 张全景片。根据 Demirjian 等人提出的牙龄，分析 L3、L4、L5、L7 和 L8 的所有发育阶段。采用独立 t 检验比较男性和女性之间的年龄差异。使用 Kendall's tau 进行秩相关系数检验，并进行 bootstrap 分析和 Bonferroni 校正，以确认与 L8 发育阶段最相似的牙齿。最后，进行生存分析以确定下颌第三磨牙缺失的早期诊断标准。
男性和女性的牙齿发育阶段存在一些年龄差异。L3、L4、L5 和 L7 的所有阶段与 L8 之间的相关系数均较高。特别是 L7 与 L8 之间的相关系数最高，而 L3 与 L8 之间的相关系数最低。
如果 L8 牙冠缺失时至少有以下两个标准（L3 的 F 期、L4 的 F 期、L5 的 F 期和 L7 的 E 期）得到满足，则可以确认 L8 缺失。
