CHANGES FOLLOWING THE USE OF PROTRACTION HEADGEAR FOR EARLY CORRECTION OF CLASS-III MALOCCLUSION

The purpose of this study was to evaluate treatment effects and posttr eatment changes following the application of elastic forces from a fac emask to the dentition for the early correction of Class III malocclus ion. Cephalograms made before and after treatment and at a minimum of 1 year follow-up (mean 3.57 years, S.D. 2.07) of 16 patients were comp ared with those of 13 untreated matched controls. Pretreatment age ran ged from 4.58 to 8.25 years (mean 6.80 years, S.D. 1.13), and mean act ive treatment time was 0.61 years (S.D. 0.15). Available study models at the three time periods were also analyzed. Treatment resulted in a significant improvement in the maxillomandibular relationship and over jet (P < 0.001). The major treatment effect was a downward and backwar d movement of the mandible and retroclination of the mandibular inciso rs. However, any skeletal and dentoalveolar advancement of the maxilla contributed to the clinically significant improvement. No differences were observed between the patients and the controls during the posttr eatment follow-up. Despite some relapse, the patients demonstrated a n et improvement in maxillomandibular relationship and overjet at the en d of followup relative to the controls. Overcorrection of the overjet during treatment may be important for maintaining a successful correct ion.