Method: The sample was composed of 65 adolescents who were in the pubertal growth spurt (evaluated by the carpal index), divided into two groups treated with two models of the Herbst appliance for 12 months. In group 1, the Herbst appliance was used on steel crowns and lingual arch and in group 2 on acrylic splints. Sagittal and vertical cephalometric measures were evaluated at the beginning (T1) and end of treatment(T2).
Result: For both groups, there was a mild restriction of anterior movement of the maxilla and an increased mandibular growth with improvement in sagittal relationship between T1 and T2; there was no difference between groups.A clockwise rotation occurred in the occlusal plane, being higher in group 2, but the facial pattern did not change in both groups (p< .001) . For groups 1 and 2, there was a vertical control of the upper molars and significant increase in the vertical position of lower molars, between T1 and T2, with no difference between groups. Also, there was a greater vertical change of upper incisors in group 2 (p< .001) and no difference was founded in the vertical position of the lower incisors between the groups.
Conclusion: Similar cephalometric changes were observed in vertical and sagittal correction of malocclusion with two types of Herbst appliance. The largest occlusal plane clockwise rotation and extrusion of upper incisors in group 2 did not affect the vertical control.”