Objective: Skeletal mandibular asymmetry (MA) is a pathological condition characterised by asymmetric mandibular growth, resulting in chin deviation and, in some cases, non-coincident dental midlines. Because it is a skeletal condition, some clinicians choose to treat it with functional appliances. The present study therefore evaluated whether functional appliances with asymmetric activation can promote more symmetrical growth of the mandibular condyles and rami. Methods: Eighty-five patients with MA were retrospectively selected based on cervical skeletal maturation stage 2 or 3, the presence of skeletal and dental Class II malocclusion, and the availability of good-quality orthopantomograms taken before and after treatment. Among the enrolled patients, 40 were treated with functional appliances to protrude and re-centre the mandible (study group), while 45 were treated only with a rapid maxillary expander (positive and treated control group). This control group was chosen because it has no direct effects on the mandible and avoided the ethical concerns associated with postponing time-sensitive treatment to recruit a negative control group. Ramus and condyle asymmetry were evaluated pre- and post-treatment using Habets’ method. The Mann–Whitney U-test was used to compare pre- and post-treatment asymmetry indices between the two groups. Results: Although both groups showed a post-treatment symmetry improvement, no statistically significant between-group differences were observed (p = 0.712, effect size r = 0.14 for ramal symmetry; p = 0.663, effect size r = −0.01 for condylar symmetry). Conclusions: Within the limitations of this study, functional appliances did not demonstrate greater skeletal effects than the positive control treatment.
Tepedino et al. (2026) studied this question.