下颌第二磨牙若紧嵌在第一磨牙远中牙冠颈部下方即不能正常萌出,而形成阻生。下颌第二磨牙阻生的确切发病率有待进一步研究,估计在3/1000以上。第二磨牙阻生后,会增加第三磨牙阻生的发病率。 作者对22例阻生的第二磨牙进行外科直立手术。有16名下颌第二磨牙阻生的患者,年龄11.7～17.9岁(平均14.1岁)。局麻下去除第二磨牙远中少量骨 If the second mandibular molars tightly embedded in the first molar distal crown below the neck that can not be normal eruption, and the formation of obstruction. The exact incidence of impacted mandibular second molars remains to be further studied and is estimated to be above 3/1000. After the second molars impacted, will increase the incidence of impacted third molars. The authors performed surgical uprising on 22 impacted second molars. Sixteen patients with impacted mandibular second molars aged 11.7 to 17.9 years (mean, 14.1 years). Under local anesthesia to remove the second molar distal a small amount of bone