Movement of Mandibular Incisors in Patients With Skeletal Class III During the Surgical Orthodontic Treatment

This study investigated changes in the morphology of the mandibular symphysis and the movement of the mandibular incisor over time during surgical orthodontic treatment for skeletal class Ⅲ.

Twenty-two patients with skeletal class Ⅲ malocclusion treated with combined orthodontic treatment, and orthognathic surgery were included. Multidetector computed tomography (CT) and lateral cephalograms were obtained from these patients to assess changes in mandibular incisor inclination, position, labial and lingual bone area, alveolar bone thickness at the mandibular central incisors and canines, and the morphological evaluation of the mandibular symphysis.

The lower alveolar bone thickness at the incisors showed a significant increase, whereas the lingual alveolar bone area significantly decreased. Additionally, the incisor mandibular plane angle (IMPA) significantly increased. Labial tipping of the mandibular incisors during presurgical orthodontic treatment resulted in the root apices moving closer to the lingual cortical bone. During postsurgical orthodontic treatment, the position of the incisor root apices remained stable, while the incisor crowns underwent lingual movement.

Mandibular incisors incline labially during presurgical orthodontics accompanied by the lingual inclination of the mandibular symphysis. These findings highlight the dynamic changes in alveolar bone and root position during orthognathic surgical treatment.