Final answer:
It is never acceptable for a licensed person to perform professional services beyond their scope and competence.
Step-by-step explanation:
It is never acceptable for a person licensed to perform professional services beyond the scope of his/her license and field of competence, as established by his/her education, experience and training. This includes, but is not limited to using an instrument or device in a manner that is not in accordance with the customary standards and practices of the dental hygiene profession.