1. a healthcare professional who specializes in dental hygiene and cleaning teeth
Usage: most common sense; typically works under the supervision of a dentist
2. a specialist in hygiene or public health practices
Usage: broader professional sense

Examples

• The dental hygienist cleaned my teeth before the dentist examined me.
• She works as a hygienist at the local dental clinic.
• The hygienist recommended flossing daily to prevent gum disease.
• A public health hygienist develops sanitation standards for hospitals.
• My appointment with the hygienist is scheduled for next Tuesday.