California Code, Business and Professions Code - BPC § 1953

(a) A registered dental hygienist, registered dental hygienist in alternative practice, or registered dental hygienist in extended functions who performs a service on a patient in a dental office shall identify himself or herself in the patient record by signing his or her name or identification number and initials next to the service performed, and shall date those treatment entries in the record.

(b) A repeated violation of this section constitutes unprofessional conduct.