Facial improvement after mandibular midline distraction and surgically assisted rapid maxillary expansion

•A 49-year-old woman had severe crowding crowding, tapered arches, previous extractions.•She was treated with mandibular midline distraction and surgically assisted RME.•3D surgical planning and osteotomy guiding wafer improved the predictability of surgery.

This case report describes the retreatment of a 49-year-old woman with severe crowding in the mandibular incisor region and tapered maxillary and mandibular arches. Treatment consisted of mandibular midline distraction and surgically assisted rapid maxillary expansion to increase arch length. The need for proper presurgical orthodontics is described, and the complications during treatment are discussed. The results of treatment, including the superimposition of 3-dimensional facial scans, are presented. The treatment approach we used is typically indicated for patients with previous extractions of all first premolars who develop significant crowding after treatment. Surgical planning in 3 dimensions and the use of a 3-dimensional designed surgical osteotomy guiding wafer should improve the predictability of this treatment approach.