Abstract: Objective To investigate the effect of magnetic-orthodontic extrusion on impacted teeth and its potential value. Methods 36 patients who received dental treatment in our hospitals from April 2008 to April 2012 were chosen as the study subjects with 29 impacted maxillary canines and 7 impacted maxillary central incisors.36 patients were then randomly divided into two groups:Group A (surgical joint fixedappliance) which underwent a surgical fenestration joint fixed appliance therapy and Group B (surgerycombinedmagnetictraction) which underwent a surgical fenestration combining magnetic traction therapy.Gingival-breaking time,into the column time,the eruption of the situation,pulp and degree of patient pain of two groups were observed. Results Compared with Group B,the average gingival-breaking time and into the column time of Group A were less,but the difference was not statistically significant ( P >0.05).Pulp vitality tests were normal in group A without root resorption and adhesion,but the traction parts of the gums and lips had obvious traction oppression signs,and patients felt haulage pain when doing such lip movements as speaking and eating.Pulp vitality tests were normal in group B without root resorption and adhesion,and there were no infections in the traction parts and no abnormalities in the gums and lips and the patients felt no pain. Conclusions Although the treatment time is slightly longer,surgical fenestration combining magnetic traction therapy has broad application prospects in treatment of the impacted teeth due to its gentle traction and less pain.

Key words: magnetic appliance, fixed appliance, ambush tooth, flap surgery