Oral cancer screenings should be quick, painless exams performed by dentists to detect early or existing signs of cancer or precancerous conditions in the mouth. These screenings can be done during regular dentist visits. VELscope inspects the tissues inside the mouth with a blue light source and a viewing scope. Healthy tissues are bright green, whereas abnormal or precancerous tissues are darker. An abnormal screening, however, does not always indicate cancer. A second scan may be scheduled to see if the same abnormalities appear again. A brush biopsy may be performed as well to ensure that the dark spots are not cancerous or precancerous.