Treatment timing for skeletal Class-III malocclusion with maxillary protraction

Objective To investigate the treatment timing for Class-Ⅲ malocclusion with maxillary protraction based on the results of long term follow-up study. Methods Twelve patients in growth spurt with Class-Ⅲ malocclusion were included and divided into two groups: early treatment and late treatment. Lateral cephalograms were taken and analyzed at three period: T_0: start of treatment; T_1: end of maxillary protraction, and T_2: 5 years after therapy. The results was analyzed by t-test. Results Early treated group showed better effect in correcting skeleton abnormality, and the long term treatment effect was stable. Conclusion Maxillary protraction treatment before the peak in skeleton growth velocity is able to induce more pronounced craniofacial changes at the skeletal level.