For which of the following is general supervision permitted?

General supervision in dental hygiene refers to the situation where a dental hygienist can perform procedures in the presence of a dentist who is not necessarily on the premises, as long as there is an established relationship and the dentist has diagnosed the condition.

Fluoride treatment falls within tasks that are able to be performed under general supervision because it is considered a preventive measure that is typically straightforward and does not require complex decision-making at the moment of care. The dentist can provide standing orders for fluoride treatments, allowing the hygienist to perform them without the dentist needing to be present.

Understanding the context of the other options clarifies why they may not fall under general supervision. Soft tissue curettage and local anesthesia generally require direct supervision due to the nature of the procedures, which involve more significant clinical judgment and potential patient risks, necessitating the presence and immediate input of a dentist. Study cast impressions may not require specific supervision but are usually done under the direct oversight of a dentist to ensure accurate diagnosis and treatment planning.

The distinction lies in the complexity and potential risks associated with each procedure, with fluoride treatments being more routine and thus suitable for general supervision.