Early changes include aphthous ulceration, which may extend up into the hypopharynx and oral cavity.

The medical term for canker sores is aphthous stamatitis.

Examples include, but are not limited to, studies of the effects of beliefs, affective states, or stress on the immune system as related to the onset, progression, or treatment of oral diseases or conditions such as periodontal diseases, caries, head and neck cancers, temporomandibular joint and/or muscle disorders, herpetic and aphthous lesions, oral manifestations of HIV infection, or oral mucosal wound healing following oral surgery.