Andrews Will A, Rudmann Adam J
Visiting Lecturer, Department of Growth and Development, School of Dentistry, UCSF, San Francisco, California; Private Practice, San Diego, California.
Private Practice, Cincinnati, Ohio.
J World Fed Orthod. 2025 Oct;14(5):274-279. doi: 10.1016/j.ejwf.2025.05.006. Epub 2025 Jul 3.
To assess anteroposterior (AP) displacements of the jaws and incisors relative to the forehead in untreated growing subjects with normal (Class I) occlusions.
Serial lateral cephalograms from 74 untreated subjects (37 female, 37 male) with Class I dental relationships were obtained from the AAOF Craniofacial Growth Legacy Collection. Mean age at T1 was 9.9 years; T2 was 17.6 years. T1 tracings were secured over millimeter graph paper with Frankfort Horizontal aligned horizontally. Superimpositions were guided by anterior cranial base structures, then shifted along Frankfort Horizontal so that glabella on T1 and T2 shared a common vertical plane (Glabella-Vertical [GV]). AP displacements of Point A (Pt A), Point B (Pt B), maxillary central incisor's FA point (U1FA), and mandibular central incisor's FA point (L1FA) were measured relative to GV. Changes in occlusal plane (OP) inclinations were also measured.
Average AP displacement at Pt A was -0.47 mm; Pt B +0.71 mm; U1FA +0.32 mm; and L1FA +0.82 mm. OP inclination decreased 2.3 on average. Displacement of L1FA was significantly different between genders (M, +1.16 mm; F, +0.47 mm; P = 0.04). No significant differences between genders were found for any other variable.
AP jaw and incisor positions were effectively static relative to GV during normal growth between ages 9 and 18 with untreated Class I occlusions. On average, no site underwent AP displacement relative to GV that exceeded 1 mm. The OP tended to rotate counterclockwise. In subjects with Class I dental relationships, pretreatment jaw, and incisor positions do not undergo significant AP changes relative to GV during growth after 9 years of age regardless of gender. GV could thus serve as a reliable AP diagnostic landmark in growing patients.
评估未经治疗的生长发育期正常（I 类）咬合患者颌骨和切牙相对于前额的前后移位情况。
从美国正畸医师协会颅面生长遗产数据库中获取74例未经治疗的I类牙关系患者（37名女性，37名男性）的系列头颅侧位片。T1时的平均年龄为9.9岁；T2时为17.6岁。将T1描图固定在毫米方格纸上，使法兰克福平面水平对齐。以前颅底结构为引导进行重叠，然后沿法兰克福平面移动，使T1和T2上的眉间点位于同一垂直平面（眉间垂直[GV]）。测量A点（Pt A）、B点（Pt B）、上颌中切牙的FA点（U1FA）和下颌中切牙的FA点（L1FA）相对于GV的前后移位。还测量了咬合平面（OP）倾斜度的变化。
Pt A的平均前后移位为-0.47mm；Pt B为+0.71mm；U1FA为+0.32mm；L1FA为+0.82mm。OP倾斜度平均降低2.3度。L1FA的移位在性别间有显著差异（男性，+1.16mm；女性，+0.47mm；P = 0.04）。其他变量在性别间未发现显著差异。
在9至18岁正常生长且未经治疗的I类咬合患者中，颌骨和切牙相对于GV的前后位置有效保持稳定。平均而言，相对于GV，没有任何部位的前后移位超过1mm。OP倾向于逆时针旋转。在I类牙关系患者中，9岁以后生长期间，无论性别，治疗前颌骨和切牙相对于GV的前后位置无显著变化。因此，GV可作为生长发育期患者可靠的前后诊断标志。
