Objective: 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.
Materials and methods: 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.
Results: 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.
Conclusion: Soft-tissue changes accompanied the underlying skeletal and dentoalveolar tissue changes after chin cup treatment.