Preserved maxillary transverse width following bilateral premolar extraction in a skeletal Class III malocclusion: a case report

Background Skeletal Class III malocclusion with simultaneous anterior and posterior crossbite is uncommon and often presents with combined sagittal and transverse discrepancies. Extraction-based camouflage treatment is traditionally associated with predictable reductions in maxillary transverse dimensions during space closure. However, rare cases may deviate from this pattern. This report describes a unique presentation in which maxillary intermolar width remained fully preserved following bilateral premolar extractions, highlighting an unusual transverse response with clinical relevance for treatment planning. Case presentation: 19-year-old woman presented with a concave facial profile, anterior and posterior crossbite, and dental crowding. She declined orthognathic surgery, and a non-surgical camouflage plan was adopted. Four premolars were extracted to create space for alignment and crossbite correction. The treatment sequence incorporated an inside-out technique aimed at maintaining transverse stability while assisting correction of the posterior crossbite, sectional archwire mechanics with adjunctive Class III elastics during space closure, and a wire-plus-aligner approach in the finishing phase for high-precision detailing. Throughout the 31-month treatment period, maxillary intermolar width remained unchanged, contrary to the transverse constriction commonly associated with extraction mechanics. Both anterior and posterior crossbite were corrected, and facial esthetics improved. Conclusion This case demonstrates an unusual transverse response during extraction-based camouflage treatment of skeletal Class III malocclusion, with complete preservation of maxillary intermolar width. Recognition of such variability may help clinicians better anticipate potential transverse outcomes when planning complex Class III camouflage treatment.