Abstract:

Abstract： First permanent molar may be positioned too mesially during eruption and result in the resorption of the distal root of the second primary molar. Ectopic eruption of first permanent molar ususlly causes the loss of the space and decrease of the arch length， and in severe cases leads to premature loss of the second primary molar. Two types of ectopic eruption of first permanent molars were identified--reversible and irreversible. Intervention should be done toward irreversible ectopic eruption. Therapy could be active or passive. Active therapy methods include separators and distalizing appliances. Passive therapy methods include dissecting the crown or extraction of second primary molar. Clinical manifestation of ectopic eruption of first permanent molar and routine therapy methods were discussed in this article.

Key words: first permanent molar, ectopic eruption

摘要：

第一恒磨牙在萌出过程中过于偏近中可导致第二乳磨牙牙根吸收。第一恒磨牙异位萌出常常造成间隙丧失和牙弓长度减少，严重者可导致第二乳磨牙早失。第一恒磨牙异位萌出分为可逆性和不可逆性，对于不可逆性异位萌出应进行积极的治疗。治疗方法包括主动治疗和被动治疗。前者常用的方法有分牙法以及采用推第一恒磨牙向后的装置；后者通常采用截冠或拔牙的方法。本文对第一恒磨牙异位萌出的临床表现和常用的治疗方法进行了阐述。

关键词: 第一恒磨牙, 异位萌出