Mystic — A dental hygienist who worked at the practice formerly headed by Dr. Gregory Lukowski at 21 Broadway is on probation after an investigation by the state Department of Public Health.

The hygienist, Karen Walker, officially was reprimanded by the health department and is required to meet several conditions during her one-year probationary period, which began Dec. 15.

According to the health department’s consent order, which she did not contest, Walker “practiced as a dental hygienist without the general supervision of a dentist and failed to comply with the standards of infection control.”

The order does not indicate that any patients became ill as a result of the violations.

The violations apparently occurred after the death of Dr. Lukowski in July 2014, when the practice was in transition to new ownership.

Walker is ordered to complete an in-person course in infection control; to obtain the services of a licensed practitioner who will help her with the implementation of an infection-control plan and monitor compliance; as well as comply with all state and federal statutes pertaining to her licensure, among other requirements.

Violation of the terms may result in suspension of her license, according to the consent order.

Reached by phone on Monday, Walker said she currently is not working because of an injury. She declined to comment further.

A message left at the Mystic dental practice seeking comment was not returned.

Maura Downes, spokeswoman for the public health department, said Walker is permitted to continue working as a hygienist as long as she meets the terms of the order.