Long-term stability of Class III malocclusion nonextraction treatment

Abstract

BackgroundThe aim of this study was to evaluate the long-term stability of successful therapy of patients with Class III malocclusion at the end of facial growth. Materials and methodsThe experimental group comprised 18 patients with Class III malocclusion treated without extractions with a mean age of 11.8 years (SD 2.8) at pretreatment, 15.7 years (SD 1.8) at posttreatment, and 24.1 years (SD 5.4) at follow-up. The control group comprised 22 subjects with normal occlusion observed during a comparable period. Intragroup treatment changes were analyzed with paired t tests, and intergroup posttreatment changes were compared with t tests. A multiple regression analysis was used to evaluate the influence of all variables in the amount of overjet relapse. ResultsIn the long-term, the experimental group demonstrated no significant change in apical base relationship. A significant decrease in overjet and overbite was observed but both remained positive. The primary factor that contributed to the overjet decrease was the mandibular growth in the posttreatment period. There were no significant intergroup differences regarding skeletal changes during the posttreatment period; however, the maxillary and mandibular incisors had significantly different behavior in the experimental as compared with the control group. ConclusionsIn the long-term, nonextraction Class III malocclusion treatment demonstrated clinical stability in 88.9% of the patients. The dentoskeletal improvements obtained with treatment remained stable during the posttreatment period. The greater amount of mandibular growth after active treatment was the major variable that determined instability of Class III malocclusion treatment.