Assessment of changes in selected parameters of Arnett's soft tissue cephalometric analysis (STCA) in patients...

Maxillary constriction in adults often requires surgically assisted maxillary expansion. While skeletal and dental changes are well described, soft-tissue effects remain less clear. This study evaluated soft-tissue changes using selected parameters of Arnett's soft tissue cephalometric analysis (STCA) after bone-borne SARME.

This retrospective observational cohort study included 42 adults (mean age 27.67 years) who underwent SARME with a bone-borne distractor. Lateral cephalograms were obtained preoperatively and 6-8 months post-expansion. Sixteen STCA parameters and angles (SNA, SNB, ANB) were measured by two calibrated observers. Statistical analysis was performed using the Wilcoxon signed-rank test and Spearman's correlation.

SARME was associated with in a mean clockwise rotation of the maxillary occlusal plane of + 1.52° and the mandibular occlusal plane of + 1.72°. Vertical soft-tissue changes included an increase in maxillary anterior height (+ 0.62 mm) and upper lip height (+ 0.56 mm). Sagittally, nasal tip projection decreased (-0.44 mm) and chin to forehead distance decreased (-3.11 mm), indicating posterior chin displacement. Airway analysis showed a significant increase only at the Pog level (PAS-Pog + 1.94 mm). SNB decreased and ANB increased significantly, consistent with mandibular clockwise rotation. No differences were found between skeletal Class II and III groups.

Bone-borne SARME was associated with measurable vertical and sagittal soft-tissue changes. Clockwise occlusal plane rotation was linked to increased facial height and posterior chin movement. STCA can support communication and planning in adult maxillary expansion.