Study On The Factors Affecting Stability During The Orthodontic Maintenance Stage

Objective:To compare the stability of functional occlusion and non functional occlusion in orthodontic maintenance stage,and analyze the related factors leading to recurrence after orthodontic treatment and the related factors of failure.Methods:a total of 74 fixed orthodontic patients over 2 years were follow up.According to the end of the orthodontic treatment whether reach the standard of functional occlusion,they were divided into functional group and non functional group.The two groups of patients were examined by functional coordination and the research model was made.When the orthodontic ending(T1)model and the return visit(T2)model were measured,the PAR score and difference were obtained by reference to the PAR index standard.Using independent sample T test(P < 0.05),the difference between the scores of the two PAR indexes was calculated to compare the differences in long-term stability of the two groups.According to the PAR index difference whether > 5 all samples were divided into recurrent group and non recurrent group,by Logistic regression analysis of multiple factors of two groups of patients' factors such as gender,age,adherence,whether extraction,growth and development,bad habits,and the third molar root out or not,find out therelated factors affecting orthodontic stability.Results:In this study,a total of 74 patients who finished the orthodontic treatment from January 1,2009 to December 31,2015 were returned visit,including 34 males and 40 females,with an average holding time of 2.73 years,35 cases of functional occlusion,39 cases of nonfunctional occlusion,28 cases of recurrence group and 46 cases of non recurrence group.The average PAR score of the functional occlusion group was(2.36)lower than that of the non functional occlusion group(5.16).The T value of the independent sample analysis showed that the T value was-4.178,and the result was statistically significant(P < 0.05).Through questionnaire and clinical examination,multiple factors logistic regression analysis was performed on patients' gender,compliance,tooth extraction,third molars status,growth and development,bad habits,and mandibular factors.The results showed that the EXP(B)value of patient compliance and orthodontic recurrence was 0.195(P < 0.05),and the EXP(B)value of growth and development and orthodontic recurrence was 0.091(P < 0.05).The other factors were not statistically significant.Conclusion:the retention of functional occlusion after orthodontic treatment is more stable than that of non functional occlusion.The factors associated with recurrence in the process of orthodontic retention are the complianceof the patients and the residual amount of growth and development.