Changes of vertical dimension and alveolar bone remodeling in patients with second molar scissors bite during orthodontic correction

The aims of this retrospective study were to assess changes of vertical dimension and alveolar bone remodeling in cases with second molar scissors bite (SB) before and after intermaxillary cross-elastics (ICE) treatment. 36 patients with unilateral SB (SB group) and 36 subjects with normal occlusion (Control group) were included. CBCT records were taken before (SB-T0) and after orthodontic treatment (SB-T1). Alveolar bone height (ABH) and thickness (ABT), tooth and alveolar bone inclination, molar and facial height were measured. No changes on the vertical dimension were observed during treatment. Surrounding alveolar bone displayed synchronous changes in the inclination with molars for both arches. After ICE, the maxillary alveolar bone was found thinner at buccal side ( P  < 0.05), while no difference was found at the palatal side. The mandibular alveolar bone was found thicker at buccal side and thinner at lingual side ( P  < 0.05). Nevertheless, no difference in the alveolar bone thickness was observed between SB-T1 group and Control group. ICE is a safe method to correct SB with stability of vertical dimension and safety of periodontal bone. Buccolingual inclination of the alveolar bone changes with the molar tooth movement, showing a bone bending tendency during SB correction.