Could you tell me what are canker sores and what are their leads to..?

Virus: Most of them are caused by the chicken pox virus that you had as a child. No quick remedy for healing them. Warm salt water rinses and baby teething numbing solutions work best.

Canker sores: = aphthous ulcers are localized surface ulcers that usually occur on the soft tissues in your mouth & are of unknown etiology. It is thought that it is related to an autoimmune response. They are very different but often confused with cold sores that occur more often on the outside of your lips & are caused by a virus (hsv-1) http://www.Ada.Org/sections/scienceandresearch/pdfs/patient_48.Pdf.

Herpes simplex: Almost everybody gets exposed to the herpes simplex virus as a child. After that first exposure, the virus takes up residence in your body for life. Some evidence has been found in mummies. So, maybe for longer than life is possible. Anyway, later on, when your resistance drops at times, these viri produce the sores. These things last about a week. Almost everybody has this condition.