Objectives: To assess whether posterior dental intrusion results in stable orthodontic and orthopedic corrections in growing retrognathic hyperdivergent patients.

Materials and Methods: The study included 14 participants (5 males, 9 females), with an average age of 13.4 ± 0.7 years at the start of treatment. The treatment lasted 3.5 years, followed by a post-treatment observation period of 3.6 years. During the initial orthopedic phase, 150 g NiTi coil springs were attached to two palatal miniscrew implants (MSIs) for maxillary intrusion, while two buccal mandibular MSIs were used to control posterior vertical dimensions. Full orthodontic treatment was then initiated to correct the malocclusions. Participants were evaluated at least 1 year post-treatment (mean follow-up: 3.6 ± 1.6 years), and results were compared to matched untreated control subjects.

Results: Compared to untreated controls, maxillary and mandibular molars showed a relative posterior intrusion of 2.8 mm and 3.7 mm, respectively, during treatment and retention. Maxillary incisors were extruded by 1.3 mm, while mandibular incisors showed 2.9 mm of relative intrusion. Key orthopedic changes included a 3.3° reduction in the mandibular plane angle (MPA), a 2.4° increase in SN-Pg, a 2.1° increase in S-N-B, and a 4.3 mm relative reduction in anterior facial height. The maxillary incisors, which exhibited 0.6 mm of intrusion relative to controls, were the only dental or skeletal measure with a statistically significant post-treatment difference between the groups.

Conclusions: Apart from the position of the maxillary incisors, the substantial dental intrusion and accompanying orthopedic changes achieved during treatment remained stable after treatment.

Keywords: Growth; Miniscrews; Orthodontics; Orthopedics; Posttreatment; Stability.