Kato Chiho, Watari Ippei, Aida Jun, Ono Takashi
Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Am J Orthod Dentofacial Orthop. 2022 Nov;162(5):636-644.e4. doi: 10.1016/j.ajodo.2021.05.018. Epub 2022 Jul 15.
In orthodontic treatment, the space left after extracting the maxillary second molar (MxM2) may be filled by the eruption of the impacted third molar (MxM3). However, little is known about the factors associated with the eruption of the impacted MxM3. We aimed to characterize the clinical factors associated with the time taken for MxM3 eruption after MxM2 extraction.
We analyzed factors associated with late MxM3 eruption (>500 days after MxM2 extraction) in 84 molars. Prespecified risk factors were entered into logistic regression models to estimate odds ratios (ORs).
The median duration between MxM2 extraction and MxM3 eruption was 302 days (interquartile range, 140-424). Significant factors associated with late MxM3 eruption included the proximity of the MxM3 root to the maxillary sinus floor (OR, 51.72), the distance between the occlusal plane of the MxM3 and the apical third of the MxM2 roots (OR, 16.56), MxM3 angulation and depth of ≥20° (OR, 5.58), ANB angle of <2° (OR, 9.05), and ≥1.5 mm distal movement of the maxillary first molar (MxM1) from its original position at the time of MxM2 extraction and MxM3 eruption (OR, 12.9). The probability of late MxM3 eruption was 0% (0 out of 30) with no risk, 6.9% (2 out of 29) with 1 risk factor, and 52% (13 out of 25) with ≥2 risk factors.
We identified 5 clinical factors associated with late MxM3 eruption after MxM2 extraction. The probability of late MxM3 eruption increased as the number of present risk factors increased. These findings can be used for risk stratification during orthodontic treatment.
在正畸治疗中，拔除上颌第二磨牙（MxM2）后留下的间隙可能会由阻生的第三磨牙（MxM3）萌出填充。然而，关于与阻生MxM3萌出相关的因素知之甚少。我们旨在确定与MxM2拔除后MxM3萌出所需时间相关的临床因素。
我们分析了84颗磨牙中与MxM3迟萌（MxM2拔除后>500天）相关的因素。将预先设定的风险因素纳入逻辑回归模型以估计比值比（OR）。
MxM2拔除至MxM3萌出的中位持续时间为302天（四分位间距，140 - 424天）。与MxM3迟萌相关的显著因素包括MxM3牙根与上颌窦底的接近程度（OR，51.72）、MxM3咬合平面与MxM2牙根根尖三分之一之间的距离（OR，16.56）、MxM3成角≥20°及深度（OR，5.58）、ANB角<2°（OR，9.05）以及上颌第一磨牙（MxM1）在MxM2拔除和MxM3萌出时从其原始位置向远中移动≥1.5 mm（OR，12.9）。无风险因素时MxM3迟萌的概率为0%（30颗中0颗），有1个风险因素时为6.9%（29颗中2颗），有≥2个风险因素时为52%（25颗中13颗）。
我们确定了5个与MxM2拔除后MxM3迟萌相关的临床因素。随着存在的风险因素数量增加，MxM3迟萌的概率升高。这些发现可用于正畸治疗期间的风险分层。
