EGF and head and neck carcinoma: The exclusion criteria consisted of factors that are known to affect the intraoral environment or saliva secretion and salivary EGF levels and were as follows: current smoking; chronic alcohol use; ongoing dental treatment; recurrent oral mucositis due to conditions other than SS; treatment with antiparkinson drugs or psychiatric drugs such as antidepressants, anti-anxiety agents, and antipsychotic agents; severe diabetes mellitus; severe reflux esophagitis; past history of head and neck carcinoma; previous radiation therapy to the head and neck region; and previous chemotherapy for cancer.