Due to the importance of milk teeth to the physical and psychological development of children, it is important to treat milk teeth as soon as they become diseased. In particular, tooth decay, which is the most common and the earliest lesion, is not easy to detect at first, and at most, it is only a little sore when drinking cold or eating hot, and even the pain will pass after a while, so it is often ignored. However, once unbearable tooth pain, swelling or swelling of the flesh of the tooth occurs, it usually means that the pulp tissue of the tooth has become inflamed or necrotic, which may lead to the “death” of the tooth and affect the developing permanent teeth and the integrity and normal bite in the future, or even cause cellulitis and bacteraemia in severe cases.