Department of Oral Medicine and Radiology, MNR Dental College and Hospital.
Priyadarshini Dental College and Hospital, India.
Leg Med (Tokyo). 2022 Jul;57:102055. doi: 10.1016/j.legalmed.2022.102055. Epub 2022 Mar 15.
Development of third molars and their influence on the dental arch is a major concern in clinical dentistry especially, orthodontics and oral surgery. Lately, their position, eruption potential and development has become a subject of interest in forensic practice. The present study was aimed to determine whether if there is any difference in the development of the mandibular third molars according to the impaction type. Orthopantomographs (n = 1112) from 478 males and 634 females between 15 and 22 years old were analysed. In each radiograph, impaction status and the developmental stage of mandibular third molars were determined. Descriptive statistics were performed at developmental stages D to H. For stage G, there was a delay by 0.74 and 0.62 years for mesioangular impaction, 0.89 and 0.33 years for horizontal impaction, 1.43 and 0.9 years for distoangular impaction and 1.74 and 1.1 years for vertical impaction, in males and females. For stage H, delay by 0.17 and 0.74 years, 0.05 and 0.06 years, 0.48 and 1.48 years and 0.62 and 0.62 years, respectively for all impaction variants in both sexes. Mean chronological age of the distoangular and vertically impacted mandibular third molars were higher in certain developmental stages than mesioangular and horizontal impactions. Our findings concluded that distoangular and vertical impaction variants mineralize more slowly than mesioangular and horizontal variants, however these differences were smaller. Therefore, no distinction is required between impaction types for dental age estimation especially in the prediction of the age of majority (18 years).
第三磨牙的萌出及其对牙弓的影响是临床牙科,尤其是正畸和口腔颌面外科的主要关注点。最近,它们的位置、萌出潜力和发育情况成为法医学实践中的一个研究课题。本研究旨在确定下颌第三磨牙的发育是否因阻生类型而存在差异。分析了 478 名男性和 634 名年龄在 15 至 22 岁之间的患者的全景片(n=1112)。在每张射线照片中,确定了阻生状态和下颌第三磨牙的发育阶段。在发育阶段 D 至 H 进行描述性统计。对于 G 期,男性和女性的近中阻生分别延迟了 0.74 年和 0.62 年,水平阻生分别延迟了 0.89 年和 0.33 年,远中阻生分别延迟了 1.43 年和 0.9 年,垂直阻生分别延迟了 1.74 年和 1.1 年。对于 H 期,所有阻生变体在两性中分别延迟了 0.17 年和 0.74 年,0.05 年和 0.06 年,0.48 年和 1.48 年,0.62 年和 0.62 年。某些发育阶段的远中阻生和垂直阻生下颌第三磨牙的平均年龄较大,而近中阻生和水平阻生的下颌第三磨牙则较小。我们的研究结果表明,远中阻生和垂直阻生变体的矿化速度比近中阻生和水平变体慢,但这些差异较小。因此,在进行牙龄估计,特别是预测成年年龄(18 岁)时,不需要区分阻生类型。