In the stomatology clinic, the possible causes of canker sores include genetic factors, traumatic canker sores, micronutrient deficiencies, and systemic diseases. 1. Genetic factors: long mouth ulcers may be caused by genetic factors, parents have recurrent mouth ulcers, immediate family members are also more likely to have mouth ulcers. 2. Traumatic mouth ulcers: ulcers caused by trauma or hard object cuts, trauma, etc., called traumatic mouth ulcers, such as the mouth inside the stump root residual crowns lead to ulcers, dentures after stimulation of mucosal tissues, etc. lead to ulcers. 3. Lack of trace elements: the body lacks trace elements for a long time, for example, zinc can repair the damaged mucosal epithelial cells, and the lack of zinc makes it difficult to repair the epithelial cells, which will lead to the formation of oral ulcers. 4. Systemic diseases: such as duodenal ulcer, ulcerative colitis patients, due to bacterial viral infections, also easy to trigger mouth ulcers. There are many other causes of mouth ulcers, and it is recommended that you seek medical treatment in a timely manner.