Topical fluoride treatment is often carried out by your hygienist after teeth cleaning. It can be administered by three different methods. The first method involves the application of fluoride solution called fluoride varnish.. This type of fluoride must be painted on the teeth with a small tip applicator. This first method has been proven to be the most effective so good for patients with high risk of having cavities. The second method of fluoride application is the tray technique, which is used to apply fluoride gels. The third method is the use of a concentrated fluoride rinse. The third method is the least effective but it is mostly preferred by patients, especially those who gag easily.