Patients don’t always know how decay is created or how to prevent it. Tooth decay is also called worm tooth, not really worm. Teeth are a kind of salt which is difficult to dissolve, although it is the hardest and most resistant tissue of human body, but it will be damaged. Salt will hydrolyze when it meets acid, and teeth will demineralize in an acidic environment, releasing calcium. When we eat, bacteria metabolize the sugar in the food and produce acid, at which point some of the calcium in the teeth is hydrolyzed. It takes about an hour before the mouth returns to a relatively alkaline environment and the demineralized teeth remineralize again. For people who do not eat snacks and sweets three times a day, the teeth can reach a balance between demineralization and remineralization, so some people do not have much caries. But if snacking every hour is eating something, this balance is broken, and the teeth will develop in the direction of gradual decomposition. In addition, sweet food is not necessarily sweet food, such as potato chips or something is not sweet, but it is starch is polysaccharide is also a kind of sweet food. That’s why some people say I don’t eat much sweets but also grow tooth decay. There are also some people who are prone to acid reflux because their stomach is not good, and they often have caries, and in this case, they need to cooperate with gastroenterology treatment. Therefore, the most important thing to prevent tooth decay is to eat less snacks and sweets, of course, brushing good teeth can help to prevent tooth decay, but it is more important to prevent periodontal disease.