Dento-skeletal changes after modified SEC III treatment followed by fixed appliances in growing patients with Class III malocclusions

<h2>Abstract</h2><h3>Objectives</h3> To evaluate the effects produced by the modified Splints, Elastics class III, and Chin cup (SEC III) treatment in growing patients with dento-skeletal Class III malocclusion followed by fixed appliances in the permanent dentition compared to untreated Class III subjects. <h3>Materials and Methods</h3> This retrospective observational longitudinal study was conducted on 40 patients with dento-skeletal Class III malocclusion aged between 7 and 11 years. Lateral cephalometric data, including eleven variables, were collected at initial (T0), intermediate (T1), and final (T2) time points. Class III patients were treated from T0 to T1, before the pubertal growth spurt, with the modified SEC III protocol, and during the second phase of treatment with fixed appliances. Final records (T2) were taken at the end of comprehensive treatment. The treated group was compared to a control group of an age-matched untreated Class III subjects. Statistical between-group comparisons were performed with independent sample <i>t</i>-tests in normally distributed data, while the Mann–Whitney test was used when data were not normally distributed. <h3>Results</h3> Comparisons at the T0 showed no statistically significant differences. Statistically significant differences were found during the T1-T0 interval. In particular, the treated group showed significant increases in SNA, ANB, Wits, SN-Pal Pl angles, and decreases in Ar-Go-Me, SN-GoMe, Pal Pl-Md Pl, Occl Pl-Md Pl angles, compared to untreated subjects. Moreover, the treated group also showed significant decreases in total mandibular length (Co-Gn). During the T1-T2, the treated group showed slight changes in the sagittal and vertical intermaxillary relationships in SNA, ANB, Wits appraisal, SN-GoMe, Occl Pl-Md Pl, as well as in the gonial angle Ar-Go-Me. <h3>Conclusions</h3> Subjects with Class III malocclusion showed significantly favorable sagittal and vertical skeletal changes after treatment with the modified SEC III followed by fixed appliances in comparison to untreated Class III subjects.