Evaluation of relapse in patients treated with facemask treatment and conventional rapid maxillary expansion: a retrospective study

This retrospective study evaluates the skeletal, dental, and soft-tissue effects of facemask treatment combined with conventional rapid maxillary expansion in growing patients with skeletal Class III malocclusion, assesses post-treatment relapse, and investigates sex-related differences in treatment outcomes. This retrospective study included 33 growing patients (18 females, 15 males) with skeletal Class III malocclusion and maxillary deficiency treated with facemask (FM) treatment combined with conventional rapid maxillary expansion (RME). The patients were categorized into three groups: the Total Group, including all patients, the Female Group, and the Male Group. Archived lateral cephalometric radiographs obtained at pre-treatment (T0), post-treatment (T1), and at the end of the follow-up period (T2) were analyzed. On each radiograph, 10 angular and 16 linear measurements were performed. The mean age of the patients included in the study was 10.89 ± 1.37 years. The patients’ mean treatment period (T1-T0) was 13.03 ± 4.56 months, with a mean follow-up period (T2-T1) of 17.94 ± 8.61 months. Post-treatment, the combined use of the FM and RME significantly enhanced maxillary development in skeletal Class III individuals and was effective in correcting overjet, whereas overbite remained stable in females but decreased in males. The mandibular plane angle (SN/GoGn) increased significantly during the treatment period, while sagittal skeletal relationships (ANB, Wits) improved significantly; however, a partial loss of treatment effects was observed during the follow-up period. No statistically significant sex-related differences were found in skeletal (except Co-A), dental (except 1/NB, IMPA, and overbite), and soft-tissue measurements. The partial loss of treatment effects observed after Class III treatment suggests that mandibular growth may play an important role in post-treatment stability. Therefore, regular follow-up until the completion of growth and the evaluation of supportive retention approaches are clinically important. The increase in the mandibular plane angle over time highlights the importance of careful treatment planning, particularly in patients with vertical growth tendencies. Sex-related differences were minimal; however, dentoalveolar adaptations in females may have contributed to improved overbite stability.