For a Dental Hygienist, which of the following procedures is expressly allowed?

The correct choice, which states that a dental hygienist is expressly allowed to take impressions for orthodontic adjustments, aligns with the scope of practice defined for dental hygienists. In North Carolina, dental hygienists have the authority to perform certain procedures that are essential to patient care, within the limits established by state regulations. Taking impressions is a procedure that falls within a dental hygienist's scope of practice, as it is crucial for creating models for diagnosing, treatment planning, and executing orthodontic adjustments.

This procedure does not require specific additional training beyond what is covered in the dental hygiene curriculum. By allowing dental hygienists to perform this task, the state acknowledges the role they play in the overall dental care team, particularly in orthodontics.

In contrast, the other procedures listed are either beyond the scope of practice for dental hygienists in North Carolina or require additional training and certification that is not typically included in the dental hygiene education program. Administering anesthetics via injection and applying antibiotic agents intravenously generally fall under the purview of dentists or specialized practitioners due to the complexity and potential risks involved. Coronal polishing, while a procedure that dental hygienists can perform, usually mandates specific training to ensure proper technique and patient safety.