Study On The Risk Of Apical Root Resorption In Orthodontic Treatment Of Maxillary Central Incisors With Short Root Anomaly

Objective: To summarize the characteristics of patients with short root anomaly(SRA)without history of orthodontic treatment through collection of cases,so as to understand relevant prevalence,and the degree of involvement as well;To evaluate the degree of root resorption of maxillary central incisors after orthodontic treatment in patients with SRA,and to explore the occurrence of orthodontic induced external apical root resorption(OIEARR),so as to provide reference for orthodontic treatment of such patients.Methods: the first part: 1288 patients,including 453 males and 835 females,were selected from the Department of Orthodontics,Hospital of Stomatology affiliated to Guangxi Medical University between November 2018 and November 2019.The Panoramic Radiographs(PRGs)and Cephalogram(Ceph)were observed,and the root-crown ratio(RootCrown Ratio,R/C)was measured according to the improved Lind metho d,and the patients with SRA were diagnosed,so as to study the prevalence rate,predilection position,severity and clinica l classification of SRA in case samples were studied.The second part: 24 SRA patients with maxillary central incisors involved were selected from the orthodontic patients in the orthodontic department of our department from 2016 to2019,including 5 males and 19 females.The maxillary central incisors of this group were taken as the experimental group.According to the matching conditions,24 orthodontic patients with normal root-crown ratio were selected,and the maxillary central incisors of this group w ere used as control.There were 48 patients,including non-extraction group(n = 26)and extraction group(n = 22).The root resorptio n grade and relative root resorption(Relative Root Resorption,r RR)of the experimental group and the control group were ev aluated by Levander and Fritz methods,and the incidence,severity and influencing factors of OIEARR between the two groups were stat istically analyzed.Results: 1.The prevalence rate of SRA in this sample was 3.1%,which was most common in women,and the average R/C was 0.86±0.08,which often involved the maxillary central incisors,followed by the maxillary lateral incisors.Most of t he clinical SRA were localized,and a few were generalized.2.There was no difference in the incidence of OIEARR between the SRA group and the control group,but the incidence of OIEARR in the tooth extraction group was higher than that in the non-extraction group.3.The OIEARR grade of the SRA group was mainly 2-3,while that of the control group was 1-2,which was more serious in SRA group.There was significant difference in r RR between the SRA group and the control group.4.Correlation analysis showed t hat treatment time and tooth extraction were related factors affecting the degree of OIEARR of maxillary central incisor in patients with SRA.Conclusion:1.The prevalence rate of SRA in the sample of this study is3.1%,which is most common in women,and the maxillary central incisor and lateral incisor are often involved.Most of the clinical SRA were localized.2.Treatment time and tooth extraction are the related factors affecting the degree of OIEARR of maxillary central incisor in patients with SRA.