混合牙列期骨性III类错合与骨性I类错合基骨及牙弓对比研究
A Comparative Study of Basal and Dental Arch in the Mixed Dentition of Skeletal Class III Malocclusion and Skeletal Class I Malocclusion

目的：通过测量混合牙列期骨性III类错合患者与骨性I类错合患者的锥形束计算机断层扫描(Cone beam computed tomography, CBCT)，对比分析上下颌牙弓、基骨弓长度与宽度差异及协调性，以期为替牙期骨性III类错合畸形治疗提供参考依据。方法：选择替牙列期骨性III类错合与骨性I类错合各30例，通过Dolphin软件处理收集到的DICOM (Digital Imaging and Communications in Medicine)医学图像数据，行三维重建并测量上下颌牙弓、基骨弓的长度与宽度，计算同一牙段牙弓宽度与基骨弓宽度之间的差值，比较骨性III类与骨性I类错牙合畸形牙弓与基骨弓宽度差值的差异。结果：1) 骨性III类错合组上颌牙弓及基骨弓长度均小于骨性I类错合组，下颌基骨弓长度大于骨性I类错合组，且差异有统计学意义(P < 0.05)，下颌牙弓长度两组对比差异无统计学意义(P > 0.05)。2) 骨性III类错合组下颌前段及中段基骨弓宽度大于骨性I类错合组，差异有统计学意义(P < 0.05)；骨性III类错合组上颌前段牙弓及上颌基骨弓宽度小于骨性I类错合组，下颌牙弓宽度及后段基骨弓宽度大于骨性I类错合组，但差异无统计学意义(P > 0.05)。3) 骨性III类错合组上颌牙弓与基骨弓宽度的差值均大于骨性I类错合组，下颌牙弓与基骨弓宽度的差值均小于骨性I类错合组，其中上颌后段牙弓宽度与基骨弓宽度差值差异有统计学意义(P < 0.05)。结论：混合牙列期骨性III类错合存在牙弓、基骨弓不调，上颌可扩大基骨弓，下颌可扩大牙弓，以期改善牙弓与基骨弓的协调性。
Objective: By measuring the cone beam computed tomography (Cone beam computed tomography, CBCT) in patients with mixed dental skeletal Class III malocclusion and Class I malocclusion, and comparatively analyzing the length and width difference and coordination of the maxcillary and mandibular dental arch and basal bone arch, to provide a reference for the treatment of skeletal Class III malocclusion. Methods: Select 30 cases of skeletal Class III malocclusion and Class I malocclusion, process the DICOM (Digital Imaging and Communications in Medicine) medical image data collected by DolPhin software, measure the length and width of the upper and lower jaw dental arch, the width of the dental arch of the same tooth segment is calculated, and the difference between the dental arch and the bony class I malocclusion is compared. Results: 1) The maxillary arch and basal arch lengths in the skeletal Class III malocclusion were lower than Class I malocclusion, the maxillary basal arch lengths were longer than Class I malocclusion, and the difference was statistically significant (P < 0.05). There was no statistically significant difference in the mandibular arch lengths between the two groups (P > 0.05). 2) The width of the anterior and middle basal bone arch in the skeletal Class III malocclusion was greater than that in the bone type I misalignment group, and the difference was statistically significant (P < 0.05). The width of maxillary anterior dental arch and maxillary basal bone arch in Class III malocclusion was smaller than Class I malocclusion, and the width of mandibular dental arch and posterior basal bone arch was larger than that in Class I malocclusion, but the difference was not statistically significant (P > 0.05). 3) The difference between maxillary arch width and basal arch width in Class III malocclusion was greater