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

Abstract

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.