Which of the following would NOT be needed for a varnish application set-up?

For a varnish application set-up, dental floss is not typically required. The primary purpose of dental floss is to clean interproximal spaces between teeth, which is not a necessary step during the application of varnish. The varnish application itself focuses on applying a protective coating to the tooth surfaces, specifically in treatments such as fluoride varnish to enhance remineralization.

Cotton rolls are often used to keep the area dry and clear of saliva, which is essential for a successful varnish application. The applicator brush allows for the precise application of the varnish material onto the tooth surfaces, ensuring that the treatment is evenly distributed. Finally, the varnish material itself is the core product being applied, which provides the protective and therapeutic benefits. Thus, while each of the other items plays a vital role in effectively applying varnish, dental floss does not serve a function in this specific procedure.