1. a person trained and licensed to provide dental cleaning and preventive care under the supervision of a dentist
Usage: most common sense; professional healthcare role
2. a specialist in hygiene or public health practices
Usage: broader, less common usage

Examples

• The dental hygienist cleaned my teeth and checked for cavities.
• She works as a hygienist at the local dental clinic.
• The hygienist explained proper brushing techniques to the patient.
• My appointment with the hygienist is scheduled for next Tuesday.
• The public health hygienist developed new sanitation guidelines for the hospital.