Division of Dental Radiology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan.
Clin Exp Dent Res. 2023 Jun;9(3):472-480. doi: 10.1002/cre2.725. Epub 2023 Mar 15.
The purpose of this study was to elucidate how masticatory muscles are involved in the generation of occlusal force.
The experiment was conducted by fabricating an experimental apparatus for a unilateral occlusion model with the masticatory muscles imparted. The experimental apparatus was fabricated by enlarging the lateral photograph of a dried adult skull specimen 3.5 times larger than that of a standard adult and drawing the outlines of the maxilla and mandible, canines and molars of the upper and lower jaws, and temporomandibular joint on a wooden board. The masticatory muscles used in the experiment were the masseter muscle, the temporalis muscle (anterior and posterior muscle bundles), and the lateral pterygoid muscle. For the measurement of the contractile force of the masticatory muscle, we used the spring scale. For the food, we used cut plastic cylinders.
The results of the experiment revealed the following: First, the occlusal force was generated under the condition that the contraction forces of all the masticatory muscles were balanced. Second, when the occlusal force was applied to food, the occlusal planes of the upper and lower jaws were parallel. Third, the occlusal force occurred perpendicular to the occlusal plane. Fourth, the occlusal force was generated with a force greater than the contraction force of the individual masticatory muscles. And finally, even if occlusal force was applied to the food, the occlusal force did not load the temporomandibular joint.
Occlusal force is not generated by the action of a single masticatory muscle but under the balanced contractile force of all masticatory muscles. The occlusal force then emerges with a force greater than the contraction force of all the masticatory muscles, and its direction occurs perpendicular to the occlusal plane.
本研究旨在阐明咀嚼肌如何参与咬合力的产生。
通过制作一个单侧咬合模型的实验装置来进行实验，该模型赋予了咀嚼肌。实验装置是通过将一个干燥成人颅骨标本的侧位照片放大 3.5 倍，并在木板上绘制上颌和下颌、上下颌犬齿和磨牙以及颞下颌关节的轮廓来制作的。实验中使用的咀嚼肌包括咬肌、颞肌（前束和后束）和翼外肌。为了测量咀嚼肌的收缩力，我们使用了弹簧秤。为了测量咀嚼力，我们使用了切割的塑料圆柱体。
实验结果表明：首先，在所有咀嚼肌收缩力平衡的情况下产生了咬合力。其次，当咬合力作用于食物时，上下颌的咬合平面是平行的。第三，咬合力垂直于咬合平面发生。第四，咬合力是在大于单个咀嚼肌收缩力的力的作用下产生的。最后，即使食物上施加了咬合力，也不会使颞下颌关节承受负载。
咬合力不是由单个咀嚼肌的作用产生的，而是在所有咀嚼肌的平衡收缩力下产生的。然后，咬合力以大于所有咀嚼肌收缩力的力出现，其方向垂直于咬合平面。
