ABSTRACT
BACKGROUND: In orthodontic treatment, there will be different degrees of external apical resorption. Severe root resorption will reduce the root/shoot ratio, reduce the stability of teeth, and even cause teeth to loosen and fall out. OBJECTIVE: To compare the difference of external apical root resorption between high torque self-locking bracket and traditional straight wire bracket in orthodontic treatment of bimaxillary protrusion patients. METHODS: Forty-nine patients with bimaxillary protrusion, aged 13-16 years, who were treated in the Hospital of Stomatology of Southwest Medical University from January 2016 to December 2019, were enrolled in this study. The patients were divided into the high torque self-locking bracket group (n=24) and the traditional straight wire bracket group (n=25). Cone beam CT was taken before and after orthodontic treatment. The root morphology and length of maxillary central incisors and lateral incisors were observed by CS 3D Imaging Software. The amount of external apical root resorption between maxillary incisor and lateral incisor was calculated. This study was approved by the Medical Ethics Committee of Hospital of Stomatology of Southwest Medical University. RESULTS AND CONCLUSION: (1) The two groups after orthodontic treatment had achieved a good correction effect. The course of treatment was shorter in the high torque self-locking bracket group than that in the traditional straight wire bracket group (P 0.05). In the same appliance group, the amount of external apical root resorption of the maxillary central incisors was less than the lateral incisors (P < 0.05). (4) Results indicate that compared with the traditional straight wire bracket, the high torque self-locking bracket may have the advantages of short treatment course and low risk of apical absorption in the orthodontic treatment of bimaxillary protrusion.
ABSTRACT
Objective@# By analyzing changes of dental arch width and length during the aligning and leveling period (non-extraction case) with two kinds of self-locking bracket, compare the difference between the active self-locking bracket with the passive bracket.@*Methods@#The data of dental arch perimeter change amount and dental arch width and length change amount (WU/L3, WU/L4, WU/L5, WU/L6, U/LL) were statistically analyzed using the correlation and regression method by comparing active and passive brackets for the correction of dental arch variations. Two different brackets for the correction of the measured values of the dental arch variations was analyzed by t-test. Results There were statistical relationships between the amount of arch perimeter increase and the amount of width and length increase. The regression equation was statistically significant (P < 0.05), It was greater impacted arch width increase to arch perimeter in the self-locking. The t-test results showed WU3, WL3, WL6, LR 4 measured values (P < 0.05) statistically significant in the active self-locking group and passive group. @*Results @#There were statistical relationships between the amount of arch perimeter increase and the amount of width and length increase. The regression equation was statistically significant (P < 0.05), It was greater impacted arch width increase to arch perimeter in the self-locking. The t-test results showed WU3, WL3, WL6, LR 4 measured values (P < 0.05) statistically significant in the active self-locking group and passive group. @*Conclusin @#Active and passive self-locking bracket have good arch expansion effecting. The active self-locking bracket is slightly dominant than the passive bracket in the expansion of the canine width whereas the active self-locking bracket is better than the passive in the expansion of the mandibular first molar and arch perimeter which should be widely applied to the appropriate cases.