关键词: 埋伏牙, 阻生第三磨牙, 牙根外吸收

Abstract: Objective To analyze the prognosis and influencing factors of external root resorption（ERR）of adjacent teeth after the removal of impacted third molar that caused ERR．Methods Thirty-two cases of impacted third molars with external root resorption caused by compression were treated．After the extraction of the impacted third molars,the prognosis of the pulp of the second molars was observed through clinical symptoms and electrical activity tests．According to their different prognoses,they were divided into a successful pulp preservation group and a failed pulp preservation group．The basic information（age,gender）,affected tooth location,and root resorption type of the two groups were compared,and the relevant factors affecting the prognosis of ERR patients were analyzed．Results The success rate of pulp preservation for mandibular ERR patients（91.67%）was higher than that for maxillary ERR patients（62.50%）（P=0.085）,and the success rate of pulp preservation for ERR not involving pulp cavity（100%）was higher than that for ERR involving pulp cavity（70.59%）（P=0.046）．There was no significant difference in basic information between the two groups（P>0.05）．Conclusions When the root resorption of the affected tooth does not reach the pulp or when the affected tooth is located in the lower jaw,the prognosis of the affected tooth after the impacted third molar removed is good． Therefore,the impacted third molar should be removed as soon as possible to prevent ERR from occurring．

Key words: impacted teeth, impacted third molar, external root resorption