Evaluation of alveolar bone defects on anterior region in patients with bimaxillary protrusion by using cone-beam CT / 北京大学学报(医学版)

ABSTRACT

Objective:To investigate the alveolar bone defects of anterior alveolar bone in patients with bimaxillary protrusion by using cone-beam computed tomography ( CBCT ) . Methods: The samples consisted of 50 patients with bimaxillary protrusion, who were assigned to the teenage group[20 cases, (13. 1 ± 1. 0) years] and adult group[30 cases, (22. 9 ± 4. 2) years] . The adult group included 9 hy-po-divergent, 11 normo-divergent and 10 hyper-divergent patients. The images were obtained by using NewTom VG CBCT and the alveolar defects were evaluated. Results:The ratio of the patients had alveo-lar bone defects was 94. 00%. Meanwhile, the defects were associated with 38. 60% of all the teeth. Most defects occurred on labial alveolar bone ( 98 . 66%); fenestration was found more in the maxillary alveolar region and dehiscence occurred more in the mandible. The dehiscences (3. 06%) and defects prevalence (30. 13%) of the teenage group were significant lower than those of the adult group (11. 73% vs. 42. 46%), P0. 05). The hypo-divergent group had lower fenestrations prevalence (22. 22%) than the normo-divergent (33. 84%) and hyper-divergent groups (37. 50%), P<0. 05. The upper central incisor had the lowest alveolar bone defect prevalence. Conclusion: Alveolar bone defects are common findings in patients with bimaxillary protrusion before orthodontic treatment. The prevalence of defects is affected by age and vertical-growth type.