MTH herbst appliance, class II elastics and Paolone-Kaitsas functional appliance in mixed dentition class II patients: a retrospective cohort study

Background: It is generally accepted that the ideal time to benefit from functional therapy in Class II patients is during the circumpubertal growth period (CVM 3–4). However, in severe cases, early intervention during the mixed dentition phase may be indicated, particularly to reduce the risk of dental trauma and to protect the child from potential bullying. The aim of this study was to evaluate the effects of the Manni Telescopic Herbst (MTH) appliance in young patients with mixed dentition, comparing the outcomes with two control groups: one treated with Class II elastics and a Wilson arch, and the other with a removable functional appliance (Paolone-Kaitsas, PK). Methods: Following statistical matching for age, sex and pre-treatment overjet, lateral cephalograms taken at beginning (T0) and at appliance removal (T1) from 30 patients treated with the MTH appliance were compared with those of 15 patients treated with Class II elastics and 15 treated with the PK appliance. Results: Regarding skeletal parameters, significant differences were observed in the mandibular sagittal position (SNB (T1-T0), p = 0.01) and in the relationships between skeletal bases (ANB (T1-T0), p = 0.03; Wits (T1-T0), p < 0.01), when comparing MTH and PK groups to the Class II elastics group. The Herbst group exhibited the most substantial skeletal changes. For dental variables, better incisor control was achieved with the removable PK appliance (Ii/GoGn T1-T0 1.513 ± 5.739, and Is/PP (T1-T0) 2.507 ± 6.482). No statistically significant difference was found regarding skeletal divergence (SN/GoGn (T1-T0), p = 0.38) when focusing on younger patients in mixed dentition phase. Conclusion: Both the fixed MTH appliance and the removable PK appliance produced greater skeletal effects compared to Class II intermaxillary elastics, even when applied during the mixed dentition phase. Although the PK group demonstrated better dentoalveolar control, when significant skeletal modifications are required in young patients with mixed dentition, the use of a fixed functional appliance - such as the Herbst - is preferable.