Aim: To compare incisal axial inclination and alveolar bone changes after intrusion using segmented (Burstone) and utility (Ricketts) arches. Methods: The sample comprised 252 incisors in 39 patients (18 to 25 years of age). Eighteen patients were treated using utility arches, and 21 patients were treated using segmented arches. Lateral cephalograms were taken to evaluate incisal movements. CT scans with a slice thickness of 1 mm were exposed, and SSD-3D and MPR images were reconstructed. For all maxillary and mandibular incisors, changes of alveolar bone height; changes of labial and lingual alveolar bone thickness at apical level (A1 and A2), 3 mm coronal from the apex (A3 and A4), and 6 mm coronal from the apex (A5 and A6); and development of dehiscence and fenestration were evaluated after 5 months of intrusion. Results: Except for the retroclination of maxillary incisors in the Burstone group, all incisors experienced proclination. The greatest alveolar bone height loss was noted in the buccal alveolar bone height of the maxillary incisors in the Burstone group and the mandibular incisors in the Ricketts group (P < .05). There were decreases of alveolar bone thickness in both groups; however, the Ricketts group showed more bone decrease. These differences were significant for the maxilla (A1, A2, A4, and A6) and the mandible (A1 and A3) (P < .05). Conclusion: Using segmented arches (Burstone) under controlled biomechanical conditions minimizes the undesirable adverse effects of intrusion forces compared with utility arches (Ricketts). ORTHODONTICS (CHIC) 2012;13:60–71.
Key words: alveolar bone, CT scan, incisor intrusion