Widefield Fluorescence and Reflectance Imaging Systems and Oral Tissue Samples in Monitoring Participants at Risk for Developing Oral Cancer

PRIMARY OBJECTIVES: I. To compare images of oral mucosa, obtained at various wavelength combinations including 350 nm, 380 nm, 400 nm, and 450 nm excitation, to standard white light images, pathologic analysis of any biopsied tissue when available, and carcinogenic progression. OUTLINE: Participants' oral cavities are inspected by a clinician using a standard white light headlamp. Participants then undergo oral mucosa examination using wide-field reflectance and fluorescence imaging, and/or fluorescence spectroscopy imaging. Standard oral brush biopsies are also performed and examined microscopically. Participants may undergo repeated imaging procedures and biopsy during subsequent follow up visits.