The formation of dental caries is mainly the result of chemical reaction between tartar and sugar in food, forming acidic substances to corrode teeth. When people eat, tartar has reacted with sugar in food, and acidic substances have been formed. It's too late to brush your teeth. Only by removing tartar before meals can the formation of acidic substances be significantly reduced, thus keeping teeth clean and healthy. Of course, brushing your teeth after meals is helpful to remove food residues, which is also necessary.