Timing for one-phase non-extraction therapy for Class II malocclusions.

AIM: To cephalometrically evaluate the role of treatment timing in relation to individual skeletal maturity on the outcomes of non-extraction comprehensive Class II therapy by means of a double-blind prospective clinical trial. SUBJECTS AND METHOD: Three groups of patients with Class II division 1 malocclusions treated with a headgear in combination with fi xed appliances and Class II elastics. Lateral cephalograms were taken of all subjects before therapy (T1) and approximately 6 months after the completion of therapy (T2). The fi rst group (23 subjects) was treated before the pubertal growth spurt, the second (24 subjects) during the pubertal growth spurt, and the third (13 subjects) at a post-pubertal stage of development. Individual skeletal maturation was appraised by means of the cervical vertebral maturation method. The average T1-T2 interval was approximately 30 months for all patients, with an average duration of treatment of 24 months. Longitudinal observations on a group of 17 subjects with untreated Class II malocclusions were compared with the treated groups by means of non-parametric statistics. RESULTS: Class II treatment performed before or during the pubertal growth spurt induced signifi cant favourable skeletal changes (restriction of maxillary advancement in pre-pubertal patients and enhancement of mandibular growth in pubertal patients). Patients treated after the pubertal growth spurt exhibited only signifi cant dentoalveolar changes. CONCLUSION: The greatest amount of dentoskeletal correction of a Class II malocclusion with one-phase non-extraction treatment occurred in patients treated during the pubertal growth spurt.