The primary role of mammalian teeth is to cut and grind food, but also as a weapon for defense or attacking enemies, for example, the elephant’s teeth can reach about 2 meters, and the king of beasts, the tiger’s teeth are as sharp and powerful as a dagger. In the process of human evolution, with the change of food, that is, from raw food to cooked food, food is becoming more and more refined, teeth show a trend of degradation, the shape becomes smaller and the number decreases. And with the liberation of hands, the role of teeth as weapons also degenerated. With the emergence of the function of speech, the human teeth again became an auxiliary organ for pronunciation, and other functions of the teeth became more prominent accordingly. Chewing is still the first major function of teeth for us. With the help of masticatory muscles, small teeth have amazing strength, with the chewing force of adult incisors being around 15 kg, while the chewing force of posterior molars can reach 72 kg. The chewing power of teeth also affects the growth and development of children and adolescents’ jaw and facial bones, and the role of teeth for food grinding and other functions is very important for our nutritional intake. Although teeth are the hardest organs of the human body, they are not renewable and self-repairing, so we still have to love them and never bite hard objects, such as the shells of nuts or even bite bottle caps. The teeth also have the role of assisting in pronunciation. Taking the violin as an analogy, the string is the vocal cords, the resonance box is the nasal cavity, and the movement of the handheld is equivalent to the adjustment of the lips, cheeks, tongue and teeth. The teeth are very important to the formation of speech, especially the front teeth. For example, when learning English mentioned the dental sound, labiodental sound, etc.. For example, if an actor has good teeth, he or she will be able to spit out words clearly. The impact of teeth on our appearance is also very big. Having white and straight teeth will undoubtedly make people more confident, brighten their faces and make them more accessible to others. There is a saying: “If the eyes are the windows to the soul, the teeth are the door knockers to the business world.” This is indeed true. Moreover, if teeth are missing and not repaired, the skin is not supported and wrinkles and folds appear, the person will look old. Therefore, it is important for people of any age to take care of their teeth, and it is important to take precautions as well as treat them early. We hope that all of us will still have strong and straight teeth at the age of 80.