Changes in mandibular length before, during, and after successful orthopedic correction of Class II malocclusions, using a functional appliance.
Forty-seven girls were successfully treated with a functional appliance (FA). To be included in this study, the rate of increase in mandibular length during treatment had to be greater than twice the mean rate for a subgroup of 20 of these patients evaluated during a pre-FA observation period. The mean mandibular growth rate was 6 mm per year while the FA was activated. In the ensuing months, cephalograms were taken at intervals coinciding with five post-FA phases, including complete edgewise treatment and retention. During the post-FA phase of initial edgewise treatment, the mandibular growth rate was dramatically reduced when compared with 47 controls matched for age, sex, and initial SN:GoGn angle. Selected individual cases are presented to illustrate the great variability in growth responses that were obtained. This study found highly significant increases in mandibular length still present 2 years after treatment, diminished but still significant gains after 3 years, and no significant difference after 4 years.
DeVincenzo
J P
JP
Department of Orthodontics, School of Dentistry, Loma Linda University, Calif.
D000202:Activator Appliances; D000293:Adolescent; D016302:Centric Relation; D002508:Cephalometry; D002648:Child; D003768:Dental Occlusion, Centric; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008334:Mandible / Q000254:growth & development*; D016037:Single-Blind Method