A Study on the Relapse change after orthodontic Treatment in skeleta class III with Reversed Occlusion.

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In order to determine at which stage the relapse occurs and what kind of change is produced in patients (18 males and 12 females) diagnosed as skeletal reversed occlusion, lateral X-ray cephalograms obtained at the first examination, at completion of active treatment and after 1 and 3 year retention were evaluated.The results were as follows.1.changes during the period from completion of active treatment to 1-year retention.1) Skeletal system :Due to changes in SNP protrusive movement of the mandible was observed.2) Dental system :Some changes occurred in the L1-mandibular plane, including inclination of front teeth on the mandible.3) Occlusal plane :The occlusal plane showed no change in a stabilized state.2.Changes during the period from 1-year retention to 3-year retention1) Skeletal systemDue to changes in SNB and SNP protrusive movement of themandible was observed.2) Dental systemThere were changes in overjet and U1-SN with labial in clination of upper front teeth.3) Occlusal plane angleThe Occlusal plane showed no changes in a stabilized state.Those results indicate that the relapse phenomena after orthodontic treatment for reversed occlusion were mandible protrusive movement in the skeletal system and labial inclination of upper and lower front teeth in the dental system and SN-occlusal plane angle was decreased in change during the period from after 1-year to 3-year retention.