Lindqvist B, Thilander B
Am J Orthod. 1982 Feb;81(2):130-9. doi: 10.1016/0002-9416(82)90037-9.
The purpose of this study was to ascertain whether the lower third molar, in combination with other variables such as facial morphology and space conditions, can contribute to the occurrence or aggravation of crowding. The subjects consisted of twenty-three boys and twenty-nine girls with impacted third molars on both sides of the mandible. The impacted molar on one side was removed, while the other, nonextracted side was used as a control. Average age at the time of operation was 15.5 years (range, 13 to 19). Close to the operation and annually for at least 3 years afterward, study casts and cephalograms (lateral, frontal, and oblique) were taken. The findings indicated that (1) despite analyses of many variables, this study has not been able to predict which patients should react favorably or unfavorably to removal of the third lower molars in cases of anticipated crowding; (2) in cases with severe crowding removal of the molars could be recommended; (3) correct proximal contacts seem to be of importance in keeping the space that is achieved by extraction, while incorrect ones may spoil it.
本研究的目的是确定下颌第三磨牙与面部形态和间隙情况等其他变量相结合时，是否会导致牙列拥挤的发生或加重。研究对象包括23名男孩和29名女孩，他们双侧下颌的第三磨牙均为阻生。一侧的阻生磨牙被拔除，而另一侧未拔牙的作为对照。手术时的平均年龄为15.5岁（范围为13至19岁）。在手术临近时以及术后至少3年每年拍摄研究模型和头颅侧位片、正位片及斜位片。研究结果表明：（1）尽管分析了许多变量，但本研究仍无法预测哪些患者在预期牙列拥挤的情况下拔除下颌第三磨牙后反应良好或不良；（2）在严重牙列拥挤的情况下，可以建议拔除磨牙；（3）正确的邻面接触对于保持拔牙后获得的间隙似乎很重要，而不正确的邻面接触可能会破坏间隙。
