Association between changes in soft and hard tissue after early chin cup treatment.

Abstract

To assess the soft tissue and to determine the potential association between changes in soft and hard tissue after early chin cup treatment in prognathic children. A total of 42 children (21 boys, 21 girls) with skeletal Class III malocclusion due to mandibular prognathism were examined before (mean age, 8.5 ± 0.5 years) and after (mean age, 11.4 ± 0.6 years) chin cup treatment. Data were compared with 25 untreated matched controls (12 boys, 13 girls) with mean ages of 8.5 ± 0.5 years at the first and 11.7 ± 0.5 years at the second observation. Lateral cephalograms were taken before and after 36 months of treatment/observation. We evaluated the changes in hard and soft tissue and the correlations between these changes in both groups. The skeletal and soft-tissue facial profiles improved significantly in the treated patients, mainly due to changes in the mandible. The chin cup group revealed significant reductions in the facial-convexity angle and lower-lip inclination, leading to a remarkable improvement in the soft-tissue facial profile. We noted similar correlations between changes in the hard and soft tissue in both groups, except for a significant correlation between a pogonion retrusion and reduction in the facial-convexity angle detected only in the chin cup group. Various correlations were observed between corresponding soft and dentoalveolar changes between groups. Soft-tissue changes accompanied the underlying skeletal and dentoalveolar tissue changes after chin cup treatment.