The gap between the teeth may be periodontal disease, dental caries and other causes. 1. Periodontal disease: If the patient has gingivitis and does not maintain good oral hygiene habits. As the patient grows older, gingivitis may gradually develop into periodontitis. Periodontitis may lead to gum recession, alveolar bone resorption and root exposure, resulting in larger gaps between teeth. Large gaps caused by periodontal disease are usually seen in older patients. 2. Dental caries: If the patient has caries on the adjacent surfaces of the teeth, it may also lead to defects on the adjacent surfaces of the teeth. When the patient eats, food can easily be embedded in the defects, resulting in a wider gap between the teeth. There are many other reasons for the gap between teeth to become larger, it is recommended that the patient timely consultation, and under the guidance of the doctor for formal treatment.