Dental hygienists are licensed health care professionals that specialize in preventing oral health problems and diseases. To become a licensed, registered dental hygienist requires successful completion of an ADA accredited dental hygiene program, The National Dental Hygiene Board Examination, and a state or regional examination. The primary responsibility of a dental hygienist is to treat and educate patients in the control and prevention of oral diseases. Typical functions of the clinical dental hygienist include assessment of health histories, evaluating and charting oral conditions, removing deposits (plaque, tartar, and stain) from the teeth, exposing and processing dental x-rays, applying preventive agents to the tooth surfaces such as fluoride and sealants, and providing individualized oral hygiene instruction services.