The ancients believed that good teeth made people healthy, and health made people live longer. Sun Simiao, a famous doctor in the Tang Dynasty, advocated "getting up 300 times in the morning". When talking about the secret of longevity, Leng Qian, a centenarian birthday star in Ming Dynasty, also emphasized that "teeth should be knocked frequently". The specific methods of fixing teeth are: knocking the mortar (back) teeth 36 times in the morning, knocking the front (front) teeth 36 times, knocking the canine teeth 36 times by mistake, and finally licking the teeth with your tongue 3 ~ 5 times. Knock your teeth once in the morning, once in the middle and once in the evening. Knocking at the door in the morning is the most important thing, because after a night's rest, my teeth will be a little loose. At this time, knocking on the teeth will not only consolidate the gum and periodontal tissue, but also excite the teeth nerves, blood vessels and dental pulp cells, which is of great benefit to dental health.

Knock: teeth collide with each other. An ancient health preserving method. Yan Zhitui of the Northern Qi Dynasty wrote "Family Instructions for Yan's Health Care": "I have a toothache, my teeth are shaking, and my diet is hot and cold. There is a way to grit your teeth when you see "Bao Puzi". Just kowtow three hundred times as early as possible, even if you go for a few days. " Tang Bai Juyi wrote in the poem "Leaving Late": "I am old, and I still have a few things to hide. Sit still at night and forget to sleep. Get up and have nothing to do, bite your teeth when you close your eyes. " Song. Zhou Mi's "Preface to the Heart": "Every afternoon, sit in clothes, face east or south, sit fully, and knock your teeth for thirty-six." Clear. Cao Yin's "Huishan Cool Song": "The breeze blows the teeth and washes the cold spring, and the boat will be moved to the tail of Taihu Lake tonight."

One of the rituals of blessing in Taoism. Knocking on the left tooth is knocking on the drum, and knocking on the right tooth is knocking on the sky, which is used to exorcise evil spirits. Knocking on the door with eight teeth is used to beat drums, communicate truth and play in the morning. Wu Songming's "Chatting under the Light, Getting the Way when Falling into the Well": "The Taoist priest is the one who sticks bamboo slips, knocks on his teeth and burns incense." The seventh time in the Water Margin: "Some people kowtow and say,' Heaven on the Red Mouth and Hell on the White Tongue'." Wake the world straight, survey boots and literature Erlang Shen: "Mrs. Han kowtows."