title: Outcomes in a 2-phase randomized clinical trial of early Class II treatment.
abstract: In a 2-phased, parallel, randomized trial of early (preadolescent) versus later (adolescent) treatment for children with severe (>7 mm overjet) Class II malocclusions who initially were developmentally at least a year before their peak pubertal growth, favorable growth changes were observed in about 75% of those receiving early treatment with either a headgear or a functional appliance. After a second phase of fixed appliance treatment for both the previously treated children and the untreated controls, however, early treatment had little effect on the subsequent treatment outcomes measured as skeletal change, alignment, and occlusion of the teeth, or length and complexity of treatment. The differences created between the treated children and untreated control group by phase 1 treatment before adolescence disappeared when both groups received comprehensive fixed appliance treatment during adolescence. This suggests that 2-phase treatment started before adolescence in the mixed dentition might be no more clinically effective than 1-phase treatment started during adolescence in the early permanent dentition. Early treatment also appears to be less efficient, in that it produced no reduction in the average time a child is in fixed appliances during a second stage of treatment, and it did not decrease the proportion of complex treatments involving extractions or orthognathic surgery.
authors.affiliation: Department of Orthodontics, School of Dentistry, University of North Carolina, CB#7450, Brauer Hall, Chapel Hill, NC 27599-7450, USA. JFC_Tulloch@dentistry.unc.edu
authors.forename: J F Camilla
authors.initials: JF
authors.lastname: Tulloch
authors.forename: William R
authors.initials: WR
authors.lastname: Proffit
authors.forename: Ceib
authors.initials: C
authors.lastname: Phillips
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000704:Analysis of Variance; D002508:Cephalometry; D002648:Child; D003818:Dentition, Mixed; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D009967:Orthodontic Appliances; D009971:Orthodontics, Corrective; D009972:Orthodontics, Interceptive; D018024:Peer Review, Health Care; D012107:Research Design; D018709:Statistics, Nonparametric; D016896:Treatment Outcome