Maxillary canine internal root resorption concomitant to orthodontic retraction; cone beam evaluation

Abstract

Introduction: The objective of this retrospective study was to investigate maxillary canine internal root resorption (IRR) concomitant to orthodontic retraction evaluated by cone beam computed tomography (CBCT). Materials and Methods: The current retrospective study was conducted on a total sample of 10 CBCT of right and left maxillary canines of 5 maxillary first premolars extraction orthodontic patients with age range between 14 to 18 years old with mean age of 15.82 + 1.74 years. The sample was selected at random from a total sample of 32 CBCT which had been previously used to study external maxillary canine root resorption (ERR) of 16 orthodontic patients. Cone beam computed tomography (CBCT) image of maxillary teeth had been taken before treatment and after canine retraction using optimal orthodontic force (150 g). Internal resorption of maxillary canines had been evaluated using much more sensitive scores previously used to study canine external root resorption. Results: the results of the current study were calculated from CBCT of 20 right and left maxillary canine teeth. The average rate of orthodontic canine retraction was 1.34 + 0.31mm/month and the average time of canine retraction was 188.75 + 45.00 days. Data interpretation: pulp and/or root canal chamber; increase or decrease in any direction, will be considered as internal resorption or build-up respectively. The results showed statistically insignificant difference in IRR between; before and after right and left maxillary canine retraction. There was also statistically insignificant correlation between internal root resorption (IRR) and rate of canine retraction. Conclusions: With the use of the appropriate mechanics for orthodontic maxillary canine retraction into the first premolar extraction space, internal root resorption (IRR) will not be expected. On the other hand the use of appropriate mechanics in orthodontics is the keystone to achieve orthodontic treatment outcome without any hazard.