Association of masticatory function with morphology and function of the central nervous system

近年来，人们对牙齿的重要作用以及与之相关的咬、嚼、咀嚼等功能进行了研究。在此背景下，本研究拟以大鼠、小鼠为实验动物和人类为研究对象，探讨口腔颌功能对其他组织器官，特别是中枢神经系统发育的影响。在一项骨质疏松（op/op）小鼠破骨活性缺陷和牙齿萌出的实验中，咀嚼功能的减少导致中枢神经系统神经元数量的减少。这种现象在正常小鼠和大鼠身上也同样被观察到，这些小鼠和大鼠受到人工减少咀嚼和体育锻炼产生的机械刺激。通过人工注射破骨细胞诱导剂，这些发现在一定程度上被消除，接近正常对照，产生牙齿萌出和咀嚼功能恢复。此外,。对大鼠牙齿的机械刺激诱导了中枢神经系统中特定的C-fos蛋白。同时，使用便携式肌电记录仪对人类的这种关联进行了研究，证明了有节律差异受试者咀嚼功能的本质。综上所述，强调来自口颌功能的外部机械刺激对中枢神经系统的发育有实质性的影响，表明牙列及其咀嚼功能在中枢神经系统发育中起着重要的作用。

In recent years, an important role of the tooth and the relevant functions such as biting, chewing and mastication has been addressed. Under such background, the present study was designed to investigate the influences of stomatognathic functions on the development of the other tissues and organs, the central nervous system in particular, by use of rats and mice as experimental animals and human subjects.In an experiment with osteopetrotic (op/op) mice involved with defects in osteoclastic activity and tooth eruption, the reduced masticatory function produced a decrease in the number of neurons in the central nervous system. Such phenomena were similarly observed in normal mice and rats subjected to artificial reduction in mechanical stimuli from mastication and physical exercise. These findings were eliminated to some extent, approaching the normal controls, by an artificial injection of osteoclast induction agents, which generate tooth eruption and recover in masticatory function. Furthermore, . mechanical stimuli to the teeth in rats induced a specific C-fos protein in the central nervous system. Meanwhile, such association in humans has been studied by use of a portable electromyogram recorder, demonstrating the nature of masticatory function in subjects with occiusal discrepancy. In conclusion, it is emphasized that external mechanical stimuli from stomatognathic functions substantially affect the development of the central nervous system, indicating an important role of the dentition and the related masticatory function.