Risk Factors of Root Resorption in Orthodontic Patients Terated with Fixed Appliance

Introduction:Orthodontic treatment is associted with a risk of root resorption.The aim of this study was to determine the risk of moderate and sever root resorption in orthodontic patients treated with fixed orthodontic appliance.   Method:A case-control study was performed on 70 orthodontic treated patients with moderate and sever root resorption and 70 controls matched for age,sex,duration of treatmant,ANB index and headgear application.Data were gathered via patients records,pretreatment  lateral cephalometry,pre and post treatment panoramic radiography and analyzed by SPSS 13,chi-square,Fischer exact and odds ratio tests.   Results:Seventy patients out of 140 have had root resorption.There was no difference in age,sex,headgear application,ANB difference and duretion of treatment between case and control groups.In case group,35 and 10 cases(50%-14.3%) and in control group 12 and 1 cases had respectively ahistory of asthma and allergy which was statistically significant.(p-value=0.000 and 0.005 respetively).The odds ratio for the association between moderate to sever root resorption and history of allergy was 4.83(95%C.I 2.217 to 10.526) and history of asthma was 11.494(95%C.I 1.430 to 1.956).   Conclusion:This case-control study showed an association between the history of allergy and asthma and increased risk of moderate to sever root resorption.But,in order to confirm these findings,other studies including well controlled experimental studies are needed.