Comparing The Rate of External Apical Root Resorption During Orthodontic Treatment in Posterior Permanent Endodontically Treated and Vital Teeth

Background and Aim : One of the concerns about orthodontic treatment is the external apical root resorption(EARR).Therefore, the aim of this study was to compare the rate of  EARR in posterior permanent endodontically treated and vital teeth after orthodontic treatment. Materials and methods: This observational and retrospective study was performed on 112 roots in 28 patients in the age range of 20 to 30 referred to the orthodontic department of Isfahan Azad University who had endodontically traeted teeth on one side of the jaw and contralateral vital teeth on the opposite side. The studied roots were maxillary first and second molars roots (mesiobuccal and distobuccal roots), mandibular first and second molars roots  (mesiolingual and mesiobuccal and distal). Two panoramic radiographs were taken before orthodontic treatment and at least one year after orthodontic treatment. In both radiographies, the ratio of crown length to root length was measured in the endodontically treated teeth and the contralateral vital tooth. The results were analyzed using Mann-Whitney test. Results: There was a significant difference in the external resorption of distal (p = 0.001) and mesial (p <0.001) roots between endodontically treated and contralateral vital teeth, but there was no significant difference between distobuccal and mesiobuccal roots of maxillary posterior permanent vital teeth (p=0.499), endodontically treated teeth (p = 0.249), mesial and distal roots of mandibular posterior permanent vital teeth (p = 0.398), endodontically treated teeth (p = 0.193).There was no significant difference in the external resorption of mesial roots of vital teeth (p. 0.075), mesial (p. 0.243) and distal (p = 0.324)roots of endodontically treated teeth between maxillary and mandibular teeth but a significant difference was observed in the distal roots in the vital teeth. (P = 0.014) and root resorption in the distal roots of the maxilla was more than the mandible. Conclusion: External apical root resorption after orthodontic treatment in posterior endodontically treated teeth was lower than vital teeth.  External root resorption, Root canal treatment,Orthodontic treatment