Orthopedic correction of growing hyperdivergent, retrognathic patients with miniscrew implants

Abstract

Traditional orthodontic treatments do not adequately address the skeletal problems of retrognathic, hyperdivergent, Class II adolescents; the few approaches that do address them require long-term patient compliance. This article introduces a novel approach using miniscrew implants (MSIs) and growth to treat retrognathic, hyperdivergent adolescents. Nine consecutive patients were evaluated at the start of treatment (aged 13.2 ± 1.1 years) and again at the end of the orthopedic phase (after 1.9 ± 0.3 years). Each patient had 2 MSIs placed in either side of the palate. Coil springs (150 g) extended from the MSIs to a rapid palatal expander, which served as a rigid segment for intruding the maxillary premolar and molars. Two additional MSIs were placed between the first mandibular molars and second premolars; coil spring (150 g) extended from the MSIs to hold or intrude the mandibular molars. Before treatment, the patients exhibited substantial and significant mandibular retrusion (Z score = -1.0), facial convexity (Z score = 0.7), and hyperdivergence (Z score = 1.6). Treatment produced consistent and substantial orthopedic effects. The chin was advanced by a mean of 2.4 mm, the sella-nasion-basion (SNB) angle increased by 2.1°, the mandibular plane angle decreased by 3.9°, and facial convexity decreased by approximately 3.2°. Questionnaires showed that this treatment approach was not painful or uncomfortable; the majority of the patients indicated that they were very likely to recommend the treatment to others. Treatment was accomplished by titrating the amount of orthodontic intrusion performed based on the individual's growth potential.