Clinical Study Of The Influence On Lower Incisor Root Resorption By Flat Bite Plate Treatment During Different Growth Period

Abstract Objective:â‘ Statistic the root resorption caused by flat bite plate treatment during different growth period, to understand the root resorption differences between young patients and adult patients, to analyze the gender impact on the situation. Methods:72 Angle's class II malocclusion patients were chosen, and divided them into experimental group and control group. The experimental group comprised of 40 patients(18 males,22 females), divided into two groups, one group is adult patients (the yongest is 17,the oldest is 24,mean age is 20.5 years) and the other group is young patients (the yongest is 10.5,the oldest is 13,mean age is 11.5 years), treated with edgewise applinces and flat bite plate. Control group,32 patients, using standard edgewise appliance treatment. In the early treatment, experimental group patients were treated with fixed maxillary appliances, meanwhile, the lower jaw did not and wear mandibular fixed appliance after remove the flat bite plate. The patients of experimental group were taken panoramic radiograph before, soon after flat bite plate treatment, wearing time 1-11 months, mean 5.49 months. The patients of control group treatmented with standard edgewise appliances were taken panoramic radiograph before treatment and 6 months after. The root resorption grade of lower incisor and the extent were measured, exclude the congenital absence of teeth, root is not fully developed, the root is not clear, curved root, root filling or had periodontal disease. Experimental group included a total of 148 teeth, the young male group included 38 teeth, and adult male group included 30 teeth, the young female group included 41 teeth, and adult group included 39 teeth. Control group included a total of 115 teeth. Reference to improved grading standards, the root resorption were divided into four grades. Using SPSS 12.0 analysis the extent of root resorption with Chi-square test, and rank sum test. Results:â‘ There were no significant difference in experimental group and control group before treatment. The root absorption of the experimental group were significantly higher than the control group after treatment. Almost no visible root resorption could found in experimental group before treatment(2.03%). about most patients had mild root resorption after treatment.â‘¡There was no statistically significant difterence before flat bite plane treatment in different growth period; there was significant difterence between young group and adult group after flat bite plate treatment and the root resorption was higher in group of adult than in young.â‘¢There was no significant difterence between male and female patients on root resorption before treatment, and there was significant difterence after remove the flat plate. specially the female showed a higher sensitivity.Conclusion:â‘ Root resorption were extent affected by flat plates;â‘¡there was significant difterence between young group (the yongest is 10.5,the oldest is 13,mean age is 11.5 years) and adult group (the yongest is 17,the oldest is 24,mean age is 20.5 years) after flat bite plate treatment and the root resorption was higher in group of adult than in young.â‘¢Different gender at different growth period have different root resorption, and the female showed a higher sensitivity.