Root Resorption Of Upper Centre Incisor With Compensation In Skeletal Class Ⅱ And Ⅲ Malocclusions

Objectives: A cephalometic study of 60 patients with upper incisor compensation in skeletalⅡandⅢmalocclusions and 60 patients in skeletalⅠmalocclusion were undertaken to determine the relationship of root resorption and upper incisor compensation.Methods: One huandred and twenty patients in Stomatological Hospital of Dalian University with fixed orthodontics treatment by Straight appliance were devided into four groups accroding to skeleta I(extraction),skeleta I(non-extraction),Ⅱ,Ⅲmalocclusion.Upper incisor tipping of skeletalⅠgroup were normal after treatment, and the average age of extraction group was 15.72±3.38 years old, non-extraction group was 15.05±3.47 years old. SkeletalⅡpatients were treated with extraction and upper incisor crown lingual compensation.SkeletalⅢpatients were treated with non-extraction and upper incisor crown labial compensation treatment. The average age of skeletalⅡandⅢgroup was 16.67±4.69,15.37±3.81 years old, respectively. All patients were healthy without surgery and incisor injury before orthodontic treatment. Paired pre-treatment and post-treatment cephalogram measurements were taken for root resorption in all groups.Results: Root resorption of centre incisor in skeletalⅡandⅢgroup after orthodontic treatment is significant(P< 0.01). The variation of root resorption in skeletalⅡand skeletal I(extraction)group is significant(P< 0.01).Conclusion: Upper incisor compensation of skeletalⅡmay be one of the important factors which increases root resorption.