An oral cancer screening is usually performed during a comprehensive or recall (check-up) exam. Screening is painless and only takes a few minutes. The dentist or hygienist will use a laser light to assess the soft tissue for cell changes that might be indicative of oral cancer. If such cell changes are present, a small biopsy will be taken and sent to a laboratory for review. If the biopsy indicates that oral cancer is present, an excision (removal) will generally be performed.