Model analysis of extraction and non-extraction crowding cases treated with Damon III appliance

Objective:To investigate the width change of dental arch in crowding cases treated with DamonⅢ appliance.Method:Dental casts of 15 extraction crowding cases and 15 non-extraction crowding cases were obtained before and after treatment with DamonⅢ appliance.Arch width was measured to access the effect of the appliance.Result:Good result could be obtained in extraction and non-extraction crowding cases using DamonⅢ appliance.The upper and lower inter-canine width of extraction cases increased significantly after the treatment.The upper inter-bicuspid width,the upper inter-first molar width and the lower inter-bicuspid width of non-extraction cases increased significantly after the treatment.Conclusion:Arch width of extraction cases increased significantly after the treatment and the change related to the direction the tooth moving.Arch width of non-extraction cases increased significantly after the treatment and the change related to how and where the crowding existed.