Dental hygienists are licensed oral health professionals who focus on preventing and treating oral diseases. While the range of services vary by state, a licensed dental hygienist provides educational, clinical, and therapeutic services that support total health through the promotion of optimal oral health. Dental hygiene services include: performing oral health assessments, dental charting, oral cancer screening, evaluation of periodontal disease, dental radiographs, plaque and calculus removal; placement of preventive agents such as fluoride and dental sealants; and educating patients on proper oral health behaviors. Dental hygienists provide the dentist with the dental hygiene diagnosis, which is a crucial element in the development of a professional treatment plan. In addition to treating patients directly, dental hygienists may also work as educators, researchers, and administrators.