The correlation between soft and hard tissue changes of mandible retruding cases after Headgear-activator treatment

Objective:To evaluate the changes of soft tissue in curing Class II division 1 malocclusion cases with Headgear-activator appliance.analyze the correlation between these changes.Methd:50 Class II division 1 malocclusion subjects who were at peak high velocity on the growth curve were divided into two groups.Standardized lateral cephalograms were taken for each patient of the two groups before and after treatment.SPSS 11.0 software package was used to calculate the mean and standard deviation,matched t-test was used to evaluate the changes of the soft tissues.the correlation between the soft tissue and hard tissue changes were analyzed Result:Most variables changed obviously(P 0.05),There was statistically significant difference.A'Ls-FH、NsPg'-FH、Z angle and GSnPg' had close relationship with mandible position and upper incisors position.Conclusion:Soft tissue profile were effectively improved.The changes result from mandible's moveing forward and upper incisior's straighting.