Cavanaugh J J
Angle Orthod. 1985 Jan;55(1):70-6. doi: 10.1043/0003-3219(1985)055<0070:TMCFSM>2.0.CO;2.
Third molars, both upper and lower, do usually erupt into the place of electively removed second molars. None of the third molars in this study group became impacted during the observation period. Second molars in this study were removed before the roots had formed on the third molars. The bifurcation line appears to be a stable reference on the panoramic radiograph. It is the Author's conclusion that the extraction of permanent second molars is best for many patients, and when judiciously applied it is a reasonably safe and conservative modality in orthodontic care.
上下颌的第三磨牙通常会萌出到被选择性拔除的第二磨牙的位置。在观察期内，该研究组的第三磨牙均未发生阻生。本研究中的第二磨牙在第三磨牙牙根形成之前就被拔除了。分叉线在全景X线片上似乎是一个稳定的参考标志。作者的结论是，对于许多患者来说，拔除恒牙第二磨牙是最佳选择，并且在谨慎应用时，它是正畸治疗中一种合理安全且保守的方式。
