The most likely cause of a small meatball is a fistula in the root tip of the tooth, which is a chronic inflammation of the alveolar bone after the pulp of the tooth becomes infected and develops further, penetrating the apical foramen, and the small meatball is an outlet for the inflammation to drain pus outward. In addition, small meatballs may also be the formation of periodontal abscess fistula, i.e., from gingivitis to periodontitis, and then to periodontal abscess process and the emergence of the fistula. However, the appearance of small meatballs in the gums can not completely exclude the possibility of tumor occurrence, such as the appearance of small meatballs in the gums need to go to a professional medical institution for diagnosis.