Associations Of Maxillary Canine Impaction And Adjacent Teeth

Objective: To assess the relationship between maxillary canine impaction and adjacent teeth in a Chinese population by using the cone-beam computed tomography(CBCT)technique.Materials and Methods: Pre-treatment CBCT scans of Chinese subjects with impacted maxillary anterior teeth and age-/sex-matched subjects without impaction were used.All CBCT records were analyzed in software programs for qualitative and quantitative variables of teeth,dental arch and skeletal components by one blinded rater.The root number of maxillary premolars,presence of incisor impaction and/or supernumerary teeth,maxillary skeletal width,maxillary arch width and root resorption of adjacent teeth,and their association with maxillary impacted canines were assessed.Possible risk factors for impacted canine associated root resorption(ICARR)were also explored.The differences among groups were compared statistically.Results: The data showed a significantly higher incidence of bifurcated maxillary first premolar root on the ipsilateral side in patients with unilateral buccal canine impaction.The prevalence of maxillary incisor impaction in the buccal impaction group was significantly higher than in the control group.Maxillary skeletal width(J-J)of subjects with incisor impaction but without supernumerary teeth were significantly smaller than that of the control group,similar to the results of subjects with maxillary buccal canine impaction.Through binary logistic regression tests,physical proximity between the impacted canine crown and adjacent roots was found to be the most dominant predictor for ICARR.Conclusions: Buccal maxillary canine impaction is associated with 1)increased prevalence of bifurcation of adjacent first premolar,2)maxillary incisor impaction and 3)increased risk of root resorption of adjacent teeth.Maxillary buccal canine impaction and incisor impactions may be coincidentally caused by anterior skeletal deficiency.Impacted canines increase root resorption of adjacent teeth mostly though physical contact(proximity<1mm).