Which of the following is a practice already in a dental hygienist's scope of practice?

Monitoring of patients receiving nitrous oxide inhalation analgesia falls within the scope of practice for dental hygienists as it is considered part of patient care during dental procedures. Dental hygienists are trained to monitor vital signs and the overall well-being of patients while they receive nitrous oxide, which is a common sedation method used in dental settings. This responsibility ensures patient safety and comfort throughout the procedure.

In contrast, certain other practices, such as placing orthodontic brackets, typically require specialized training beyond that of a dental hygienist and may fall under the purview of orthodontists or dentists. Exposing radiographs is often allowed for dental hygienists, but it may come with specific restrictions depending on the regulations of the state or practice facility. Finally, performing all preventive dental procedures could be misleading, as there are certain advanced procedures that may not be within a dental hygienist's scope, emphasizing the importance of understanding the boundaries of practice in the profession.