A Study of Factors Inducing Root Resorption During Functional Occlusion in Pre-orthodontic Patients

Objective: To find some factors inducing root resorption due to functional occlusion in patients before ortho-dontic treatment. Methods: OPGs were used to screen patients who had anterior root resorption and the periapical radio-graphs were taken to make sure from the patients who were examined in the Department of Orthodontics of Xiangya Hospital since July 2007 till March 2008. 14 patients who had Ⅱ-Ⅲ degree anterior root resorption were chosen as patient grou, while 14 patients who had no root resorption were chosen as control group controlled by age and gender. Clinical examina-tion , model analysis and Denar mark Ⅱ articulator analysis were done for each patient to study the aspects of functional oc-clusion. T test was used for statistic analysis by Spss14.0 software. Results: The results obtained from occlusion was not significant. However the result obtained from the occlusal interference was more in the experiment group than in the control group and the difference in the number of occlusal interferences during the lateral movement of the anterior teeth was signifi-cant (P< 0.05 ) in Denar mark Ⅱ examination. The occlusal interference was not significantly different in the posterior seg-ment during the lateral excursion of the mandible. Conclusion: The occlusal interference of the anterior teeth during the mandibular movement increased the incidence of root resorption.