锥形束CT在评价双颌前突患者前牙区牙槽骨缺损中的应用

Evaluation of alveolar bone defects on anterior region in patients with bimaxillary protrusion by using cone-beam CT

目的:应用锥形束CT(cone-beam computed tomography,CBCT)评价治疗前双颌前突患者前牙区牙槽骨缺损情况。方法:选取50名未经正畸治疗的患者,根据年龄分为成人组[30例,平均(22.9±4.2)岁]与青少年组[20例,平均(13.1±1.0)岁],其中成人组根据垂直骨面型分为低角组(9例)、均角组(11例)与高角组(10例),所有患者在相同参数条件下进行CBCT扫描,在其CBCT图像上诊断牙槽骨开窗与开裂的情况并分析其分布特征。结果:双颌前突患者发生牙槽骨缺损的人数比为94.00%。所有接受检验的牙齿牙槽骨缺损发生率为38.60%。牙槽骨缺损绝大多数发生在唇侧(98.66%);牙槽骨开窗主要发生在上颌,而骨开裂主要发生在下颌。青少年组牙槽骨开裂(3.06%)及骨缺损(30.13%)发生率明显低于成人组的骨开裂(11.73%)及骨缺损(42.46%)发生率,P<0.05;而两组的牙槽骨开窗发生率差异无统计学意义(P>0.05)。低角组骨开窗(22.22%)的发生率低于均角组(33.84%)和高角组(37.50%),P<0.05。牙槽骨缺损发生率最低的牙位为上颌中切牙。结论:双颌前突患者在正畸治疗前即存在广泛的牙槽骨缺损,缺损的发生率受年龄、垂直骨面型等因素影响。

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%）, P〈0. 05; while there was no significance of the fenestrations prevalence between the two group （P〉0. 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.