Orthodontic Department, St Louis University, MO, USA.
Angle Orthod. 2011 Mar;81(2):211-6. doi: 10.2319/051010-252.1.
To characterize the mixed-longitudinal craniofacial growth of untreated, white, Class III subjects 6 to 16 years of age.
Serial cephalograms of 19 females and 23 males with Class III malocclusion were evaluated at three time points (6-8, 10-12, and 14-16 years of age). A similar number of Class I controls were randomly selected and matched for age and sex. The cephalograms were traced and digitized, and 20 variables were evaluated. Growth patterns were quantified, and class and sex differences were evaluated using multi-level analyses.
In comparison with Class I subjects, Class III subjects had significantly (P ≤ .05) larger mandibular plane angles, gonial angles, mandibular ramus heights, mandibular corpus lengths, and SNB angles, with differences that were maintained between 6 and 16 years of age. Maxillary lengths and ANB angles were significantly smaller and remained smaller in Class III subjects than in Class I subjects. Lower face height, maxillary-mandibular differential, and mandibular body length were also significantly larger and increased significantly more between 6 and 16 years of age in Class III subjects. The WITS appraisal was significantly smaller in Class III subjects and decreased significantly more over time. Most linear measures showed significant sex differences favoring males; the angular measures and anteroposterior (AP) maxillomandibular relationships showed no sex differences.
The AP maxillomandibular relationship of Class III subjects worsens over time. AP discrepancies are primarily due to excessive mandibular growth, which produces a protrusive, hyperdivergent phenotype. The AP discrepancies of males are larger than those of females, with differences increasing over time.
描述未经治疗的白种人 III 类错[牙合]患者 6 至 16 岁时的混合性纵向颅面生长特征。
在三个时间点（6-8 岁、10-12 岁和 14-16 岁）评估了 19 名女性和 23 名男性 III 类错[牙合]患者的连续头颅侧位片。随机选择了数量相同的 I 类正常[牙合]对照者，并按年龄和性别进行匹配。头影测量片经描迹和数字化后，评估了 20 个变量。使用多水平分析量化生长模式，并评估类别和性别差异。
与 I 类对照组相比，III 类组的下颌平面角、下颌角、下颌升支高度、下颌体长度和 SNB 角显著更大（P ≤.05），且这些差异在 6 至 16 岁期间持续存在。上颌长度和 ANB 角明显较小，且 III 类组的这些角度始终小于 I 类对照组。下面高、上颌-下颌差和下颌体长度也显著更大，且在 6 至 16 岁之间增加更显著。WITS 评价也明显更小，且随时间推移显著减小。大多数线性测量值显示出有利于男性的显著性别差异；角测量值和前后向（AP）上下颌关系无性别差异。
III 类患者的 AP 上下颌关系随时间恶化。AP 不调主要是由于下颌过度生长所致，这产生了前突、高角的表型。男性的 AP 不调大于女性，且随时间推移差异增大。
