Angle Orthod. 2020 Nov 1;90(6):851-856. doi: 10.2319/121719-809.1.
To compare second molar angulation to the occlusal plane with cephalometric measurements corresponding to AP skeletal discrepancy.
72 patients' pre-orthodontic records were analyzed. A plane was constructed along the cusps of the upper second molar and measured to a proxy for the occlusal plane. The angle between the planes was measured. ANB, Wits appraisal, U1-SN, IMPA, A-B perpendicular to Frankfort, and overjet were measured on the patients' cephalograms. Generalized additive mixed model analysis was performed to analyze the relationship between the second molar angulation and the cephalometric measurements.
All six cephalometric measurements showed a significant relationship with the second molar angulation, with Class III patients having a larger angle than Class II and I patients.
Class III patients have upper second molars that are significantly tipped from the occlusal plane. The second molars require special attention for correction prior to orthognathic surgery for Class III patients in order to avoid deleterious effects from the malpositioned teeth.
比较第二磨牙倾斜角度与牙合平面，以及与对应矢状骨不调的头影测量值。
分析了 72 名患者的正畸前记录。在上颌第二磨牙牙尖处构建一个平面，并测量到牙合平面的一个替代物。测量两平面之间的角度。在上颌头颅侧位片上测量 ANB、Wits 评价、U1-SN、IMPA、A-B 与法兰克福平面垂直和覆𬌗。采用广义加性混合模型分析第二磨牙倾斜角度与头影测量值之间的关系。
所有六项头影测量值均与第二磨牙倾斜角度呈显著相关，III 类患者的角度大于 II 类和 I 类患者。
III 类患者的上颌第二磨牙明显从牙合平面倾斜。对于 III 类患者的正颌手术，第二磨牙需要特别注意矫正，以避免牙齿错位带来的不良影响。
