BENEFIT OF EARLY CLASS-II TREATMENT - PROGRESS REPORT OF A 2-PHASE RANDOMIZED CLINICAL-TRIAL

Preadolescent children with overjet greater than 7 mm were randomly as signed to observation only, headgear (combination), or functional appl iance (modified bionator) and were monitored for 15 months. Of the 166 patients who completed this first phase of the trial, 147 continued t o a second phase of treatment. The data from the first 107 patients to complete phase 2 are available and form the basis of this progress re port. During phase I, on average there was no change in the jaw relati onship of untreated children, but 5% showed considerable improvement a nd 15% demonstrated worsening. Both early-treatment groups had a signi ficant average reduction in ANB angle, more by change in maxillary dim ensions in the headgear group and mandibular growth in the functional appliance group. There were wide variations in response, however, with only 75% of the treated children showing favorable skeletal response, Failure to respond favorably could not be explained by lack of cooper ation alone. The preliminary results from phase 2 show that, on averag e, time in fixed appliances was shorter for children who underwent ear ly treatment, but the total treatment time was considerably longer if the early phase of treatment was included. Only small differences were noted in anteroposterior jaw position between the groups at the compl etion of treatment, and the changes in dental occlusion, judged on the basis of Peer Assessment Rating scores, were similar between groups, Neither the severity of the initial problem nor the duration of treatm ent was correlated with the occlusal result. The number of patients wh o required extraction of permanent teeth was greater in the early func tional appliance group than in the headgear or control group. The opti on of orthognathic surgery was presented more often in the cases of ch ildren who did not undergo early treatment, but surgery was accepted o r was still being considered almost as frequently in the previous head gear group as in the controls, less often in the patients previously t reated with functional appliances.