Effective timing for the application of orthopedic force in the skeletal class III malocclusion.

The purpose of this study was to investigate the most effective treatment timing with the chin cup in the treatment of the skeletal Class III malocclusion. The materials consisted of sixty-one cephalometric roentgenograms of seventeen males and forty-four females treated with the chin cup. Ages of children in the sample ranged from 3 years 11 months to 12 years 8 months at the beginning of active treatment. The A-B differences before and after treatment were measured to analyze the skeletal change that occurred. although the anterior cross-bite was corrected in all cases, the final values of the A-B differences were dependent upon the age treatment was started and the level of disharmony before treatment. The final values showed more improvement in the younger age group in the group with milder disharmony before treatment.