Study On The Influential Factors Of Orthodontics On The Change Of Root Length In Root Canal Therapy Teeth

ObjectiveIn this experiment,cone beam computed tomography(CBCT)was used to study the root resorption of patients before adafter orthodontic fixation,and to explore the influence of root canal therapy on root resorption and the influencing factors of root canal therapy teeth in the process of orthodontic treatment,so as to provide a reference for the assessment of root resorption risk of root canal therapy teeth before orthodontic treatment and the prevention of serious root resorption after orthodontic treatment.MethodsOn the basis of inclusion criteria,96 patients from the Orthodontics Department of Henan Stomatological Hospital from 2015 to 2019 were selected,including 45 male patients and 51 female patients.According to the grouping criteria--the dental pulp status,age,sex,tooth position and treatment time,they were divided into experimental group(root canal treatment teeth),control group(live pulp teeth);adult group(greater than 16 years),and children group(less than 16 years old);male group,female group;anterior teeth group,posterior teeth group;upper teeth group,lower teeth group;less than 2 years group,more than 2 years group.We collected the CBCT images of each patient before and after the correction,and imported the Invivo5.2 software for 3D reconstruction.Then we measured the length of the tooth,that is,the maximum straight line from the incisal edge or the cusp to the apex.and calculated the amount of the external apical root resorption,that is,the difference between the tooth length before and after orthodontic treatment.Finally,we used Microsoft office to sort the results and import SPSS 19.0 statistical software for data analysis.Results1.After orthodontic treatment,the root canal therapy teeth and the root of the vital pulp teeth were slightly absorbed.The average amount of external apical root resorption of anterior teeth and posterior teeth in the experimental group were(0.92±0.29)mm and(0.59±0.17)mm,respectively,and that of anterior teeth and posterior teeth in the control group were(1.09±0.25)mm and(0.79±0.17)mm,respectively.In this study,the external apical root resorption of the root canal therapy teeth before and after orthodontic treatment was less than that of the opposite homonymous pulp teeth,the difference was statistically significant(P<0.001).2.In the experimental group,the average amount of external apical root resorption was(0.79±0.32)mm for male and(0.76±0.28)mm for female,(0.79±0.33)mm for upper and(0.77±0.27)mm for lower teeth.There was no significant difference in the amount of external apical root resorption between genders and the upper and lower teeth before and after orthodontic treatment(P>0.05).3.In the experimental group,the average amount of external apical root resorption was(0.86±0.36)mm for adults and(0.71±0.22)mm for children;(0.92±0.29)mm for anterior teeth and(0.59±0.17)mm for posterior teeth;(0.69±0.22)mm for patients less than 2 years and(0.83±0.33)mm for those more than 2 years.There was significant difference in the root length between the adult group and the child group,the anterior and posterior teeth position group and the treatment time group before and after orthodontic treatment(P<0.05).4.Age and anterior and posterior tooth positions are factors affecting the external apical root resorption of root canal therapy teeth after orthodontic treatment.The amount of external apical root resorption of adult teeth is more than that of children,and the anterior teeth is more than that of posterior teeth.It is not yet believed that gender,upper and lower teeth position,and treatment time have effects on the external apical root resorption of root canal therapy teeth.Conclusion1.After orthodontic treatment,there was a significant difference between the external apical root resorption of the root canal therapy teeth and the living pulp teeth.The amount of external apical root resorption of root canal therapy teeth was less than that of the opposite living pulp teeth.2.There was no significant difference in the length of the teeth before and after orthodontic treatment between the gender and the upper and lower positions.3.Age,anterior and posterior tooth positions are influencing factors for external apical root resorption after orthodontic treatment.It is not yet considered that gender,upper and lower positions,and treatment time have effects on external apical root resorption.