An air polisher can be used by a dental assistant if they are:

The correct choice reflects that air polishing is a function that requires specific legal and training parameters to be met by dental professionals. In many states, including Oklahoma, dental assistants do not have the legal authority to perform restorative procedures, which includes the use of an air polisher, unless they meet certain education and supervision criteria established by state law and dental boards.

This position underscores the importance of teamwork within the dental practice and the necessity for regulated actions in patient care. Only licensed dental hygienists or dentists are typically allowed to perform procedures involving air polishing, emphasizing the role of proper training and qualifications in ensuring patient safety.

While other options suggest circumstances under which an assistant might perform the task, they do not align with the legal restrictions placed on dental assistants regarding the use of specialized dental equipment without the necessary qualifications and oversight.