Department of Orthodontics, Faculty of Dental Sciences, Sri Ramachandra Institute of Higher Education and Research, Chennai, India.
Department of Orthodontics, SRM Dental College, Ramapuram, Chennai, India.
J Orofac Orthop. 2024 Sep;85(5):340-349. doi: 10.1007/s00056-023-00450-w. Epub 2023 Feb 24.
Cranial base flexure is an overlooked topic in craniofacial research. The aim of this retrospective observational study was to compare a new parameter, the planum clival angle (PCA), which represents cranial base flexure, in skeletal class I, II, and III malocclusions using cone beam computed tomographic images (CBCT) and correlate PCA with the stages of the fusion of the spheno-occipital synchondrosis (SOS).
A total of 125 CBCTs were divided into two groups based on chronological age (19-25 years and 12-18 years). The CBCT images from 57 subjects (19-25 years old) were categorized into three groups based on their skeletal malocclusion for measuring PCA and cranial base angles (CBA). In the second group, comprising 68 CBCT data sets of individuals in the age group of 12-18 years, the PCA angle was correlated with stages of fusion of the SOS. Data were statistically analyzed using independent samples t test, one-way analysis of variance (ANOVA, intergroup), Pearson correlation, and χ test.
There was a statistically significant linear correlation (P < 0.001) between the two parameters PCA and CBA but no significant difference was found in PCAs between the three groups. One-way ANOVA to compare the PCA values in the three stages of fusion of the SOS revealed a highly significant relationship in male subjects (p < 0.001), thereby, suggesting that as fusion progresses, the planum clival angle increases. The χ test to compare the planum clival angle in males and females revealed that SOS fusion occurred earlier in females.
There is a constant dynamic change in the value of the parameter PCA that progresses until completion of SOS fusion. The SOS fuses earlier in females. Assessment of the stage of fusion of the SOS can be used in deciding whether growth modification of the craniofacial complex is still possible during orthodontic therapy.
颅底弯曲是颅面研究中被忽视的一个课题。本回顾性观察研究的目的是比较一个新的参数，即代表颅底弯曲的斜坡平面角（PCA），在骨骼 I 类、II 类和 III 类错颌畸形中使用锥形束 CT 图像（CBCT），并将 PCA 与蝶枕结合处（SOS）融合阶段相关联。
总共 125 个 CBCT 根据年龄（19-25 岁和 12-18 岁）分为两组。根据骨骼错颌情况，将 57 例（19-25 岁）CBCT 图像分为三组，用于测量 PCA 和颅底角（CBA）。在第二组中，包括 68 例年龄在 12-18 岁的个体的 CBCT 数据集，将 PCA 角与 SOS 融合阶段进行相关性分析。使用独立样本 t 检验、单向方差分析（组间）、Pearson 相关和 χ 检验对数据进行统计分析。
PCA 和 CBA 之间存在显著的线性相关（P < 0.001），但三组之间的 PCA 无显著差异。在比较 SOS 融合三个阶段的 PCA 值的单向方差分析中，男性受试者具有高度显著的相关性（p < 0.001），因此，随着融合的进展，斜坡平面角增加。比较男性和女性的斜坡平面角的 χ 检验表明，女性的 SOS 融合较早。
参数 PCA 的值存在持续的动态变化，直到 SOS 融合完成。女性的 SOS 融合较早。评估 SOS 的融合阶段可用于决定在正畸治疗期间颅面复合体的生长修正是否仍然可行。
