Participants in this study will have an examination of the mouth. A photograph will be taken of any abnormal areas inside the mouth. Then a small probe, about the size of a large ink pen, will be placed gently against one to two abnormal appearing areas, and one normal appearing area inside the mouth. The probe will expose the oral lining to a small amount of light. Some of this light will be reflected back into the probe, and be picked up by a computer. Pictures will be made of the tissue.