In most cases, patients receive fluoride varnish right after cleaning. If this is the scenario, there is a chance that your teeth might be sensitive.
Fluoride varnish contains a higher fluoride concentration than tap water, toothpaste, and food. Therefore, you will need to wait for about six hours before you take alcohol or any hot drink or use a mouthwash. Cold drinks are allowed shortly after treatment since they can also soothe the gums.