Abstract
Impacting the posterior of the maxillary bone is effective in treating skeletal open bite with retrognathic mandible. However, a slight relapse has been observed in long-term stability following impaction of the upper molar segment. We report the retention of two skeletal open bite cases five years after surgery, each treated with multi-segmented Le Fort Ⅰ osteotomy （impaction of upper molar segments） and bilateral sagittal split ramus osteotomy （advancement and counterclockwise rotation of the mandible）, respectively. Case 1: Skeletal open bite with root resorption of incisors. During surgery, the upper molar segments were impacted 5mm, the upper incisor segment was impacted 3mm, and the mandible （lower incisors） was advanced 4mm and moved upwards 5mm. Five years after surgery, the upper molars extruded 2mm and the mandibular plane angle increased 3.7 degrees. Root resorption progressed during treatment. Case 2: Skeletal open bite with temporomandibular joint deformity. Pre-surgical orthodontic treatment was followed up with surgically assisted rapid palatal expansion and extraction of the upper first premolars. During surgery, the upper molar segments were impacted 5mm, the upper incisor segment was impacted 3.5mm, and the mandible （lower incisors） was advanced 1mm and moved upwards 4.5mm. Five years after surgery, there were no significant changes. A slight relapse was observed in one of two skeletal open bite cases treated with multi-segmented Le Fort Ⅰ osteotomy and bilateral sagittal split ramus osteotomy.
