Which statement about fluoride varnish is true?

Fluoride varnish is a highly effective topical fluoride treatment used primarily for its cavity-preventive properties. One important aspect of its application is that it can be used in the presence of calculus. This characteristic is significant because calculus does not prevent the fluoride varnish from adhering to the enamel effectively. The varnish can be applied directly to the teeth, allowing it to provide benefits regardless of the state of the teeth, including the presence of calculus or any other surface conditions.

The approval of fluoride varnish as a cavity preventive agent by professional organizations like the American Dental Association (ADA) and the Food and Drug Administration (FDA) highlights its established efficacy and safety for use, particularly in children and at-risk populations. Therefore, while the statement claiming its application in the presence of calculus is true, the other aspects regarding its approval and application in children's dentistry are also vital for understanding its role in preventive care.