When adjacent caries occurs, a filling is recommended. If neighboring caries is not treated, it may cause adverse reactions such as food impaction, pulpitis, and affecting aesthetics as follows. 1. Food impaction: Because caries occurs in the neighboring surface, the normal contact area of the neighboring surface will be destroyed, and when eating, the food is not blocked by the contact area, so it is very easy for food impaction to occur. 2. Pulpitis: because of the hidden location of adjacent surface caries, daily cleaning can not be cleaned, so the development speed is faster, when the bacteria invade the pulp tissue, it will cause pulpitis. 3. Impact on aesthetics: Caries tissue is usually black, if the adjacent caries occurs in the front teeth, it will affect the aesthetics. If the adjacent surface caries is serious or accompanied by other symptoms, it is recommended to go to the hospital in time.