title: Timing the early treatment of Class II, division 1 malocclusion--clinical and research considerations.
abstract: The aim of this study was to evaluate the correlation between timing of emergence of the permanent teeth and sagittal occlusal changes in children enrolled in a prospective clinical trial of Class II, division 1 treatment. The children, ages 7.2-13.3 years, met strict inclusion criteria and were assigned at random to treatment with either a headgear or a Fränkel functional appliance. Relationships between maxillary and mandibular first molars and canines, as well as overjet, were measured with digital calipers on casts made every 2 months and mounted on a SAM II articulator. The emergence of a permanent tooth was scored on a scale from 1 to 3, depending on the eruptive level of the tooth from cutting through the gingiva (1) to reaching the occlusal table (3). Specifically, emergence of the second premolars (PM2) and permanent second molars (M2), the most adjacent teeth to the first molars, was evaluated as it interacted with the development of the sagittal occlusion. Treatment of the distocclusion was as effective in late childhood as in mid-childhood. Within each appliance group, the emergence of PM2 and M2 did not affect the amount of progress toward Class I significantly (p > 0.05), indicating that improvement from distocclusion to neutrocclusion with each appliance is not influenced by the timing of emergence of these teeth. Although these findings support a one-phase treatment starting in the late mixed dentition, earlier intervention in mid-childhood may be required in the presence of several developmental conditions, or when the dental and skeletal development deviate significantly in the individual patient.
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001641:Bicuspid / Q000502:physiology / Q000503:physiopathology; D002648:Child; D003818:Dentition, Mixed; D005260:Female; D006801:Humans; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008445:Maxillofacial Development; D008963:Molar / Q000502:physiology* / Q000503:physiopathology; D009971:Orthodontics, Corrective / Q000379:methods*; D014078:Tooth Eruption; D014094:Tooth, Deciduous