Mandibular Advancement after Pubertal Peak with Acrylic Splint Herbst Appliance Anchored to Four Miniscrews: A Retrospective Controlled Study

Objectives: The treatment of class II patients with mandibular retrusion often involves the use of a Herbst appliance, due to its efficiency and reduced need for compliance. Despite skeletal benefits, undesired dental effects, caused by anchorage loss, could reduce mandibular advancement, especially after the pubertal peak. Although the period between cervical vertebral maturation (CVM) 3 and CMV4 is considered the best choice to maximize the orthopedic outcome, clinicians cannot always treat patients during this ideal time window, as they present at their first visit later. The goal of this study is to evaluate whether the combination of an acrylic splint Herbst appliance with skeletal anchorage and elastic chains in both the upper and lower arch (Skeletal Therapy Manni Telescopic Herbst 4: STM4) could improve the efficiency of functional treatment also in CVM 5-6 patients. Methods: Lateral cephalograms of 10 consecutively treated patients taken at the beginning and at the end of the Herbst phase were analyzed and compared with those of 10 untreated patients of the same sex, age, malocclusion, and skeletal maturation. Results: According to the Pancherz analysis, the treated group of patients showed the significant advancement of the pogonion (4.75 mm), with a reduction in ANB (-3.3 degrees) and Wits (-4.15 mm). The combination of miniscrews and elastic ligatures allowed the labial tipping of the upper incisors (+6.65 degrees) and limited the labial flaring of the lower ones (+3.05 degrees), maintaining the overjet needed for mandibular advancement. Conclusions: The STM4 technique might be an effective protocol for skeletal class II correction after the pubertal peak since it significantly reduces unfavorable dental compensations, increasing the skeletal effects and the esthetic outcome of the orthopedic treatment.