This may seem obvious to dental professionals yet I did not know that continued rubbing of my denture against a canker sore prevented the canker sore from healing. My dentist made an adjustment to the denture when he heard my complaint of pain but he didn't tell me the canker sore was caused by the denture rubbing when i chew. My MD flet canker sore is caused by herpes simplex 1. this didn't make sense to me yet he gave me a prescription for Valtrex which is thought to maybe help healing of canker sore. He gave me a referral to a Dental Surgeon who told me to get the remaining two teeth on my lower gum extracted but he did not say the canker sore was caused by the denture rubbing. None said the continued rubbing would prevent the canker sore from healing. I realized the canker sore was not healing because of the continued rubbing when my dentist told me to eat without the dentures but still he didn't tell me the continued rubbing was the reason the canker sore did not heal. I was getting one canker sore after another for five months! the last canker sore was bothering me for seven weeks until i learned that continued rubbing of the sore by the denture was the problem. I hope others can learn from this post. I hope dental professionals be specific when speaking with lay people about canker sore and denture.