A follow-up study of early treatment of pseudo Class III malocclusion.

This study investigated the long-term outcome of 27 consecutive young patients diagnosed with pseudo Class III malocclusion treated with simple fixed appliance (2 x 4 appliance), which resulted in a positive overjet in all cases. Of the original sample of 27 patients, 25 patients (93%) were examined at the five-year follow-up. Two patients dropped out soon after the active treatment was completed. Of the remaining 25 patients, 20 patients had had no other treatment other than treatment with 2 x 4 appliance, and the other five patients had undergone additional comprehensive fixed appliance therapy because of crowding. Lateral cephalograms were obtained before and after active treatment with the 2 x 4 appliance and at five-year follow-up. The long-term results showed that at the five-year follow-up all 25 patients still maintained a positive overjet. The immediate treatment outcome in the sagittal plane was the same for those who had had 2 x 4 appliance treatment only and those who had had additional treatment with comprehensive fixed appliance treatment, but lower face height increased (P < .01) and the mandibular plane angle opened (P < .05) more in those who had had additional treatment, comprehensive fixed appliance treatment. During the five-year follow-up period, the dental compensation and the growth of the jaw were similar in both groups. In conclusion, in young patients diagnosed with pseudo Class III malocclusion and treated early with a 2 x 4 appliance, the overjet was corrected, and the treatment result was maintained in the long term.