Because dental whitening gel is considered tangible personal property, dentists who sell the gel to their patients should collect and remit sales tax. Dentists should provide a Resale Certificate, Form ST-3, to their vendors when purchasing the whitening gel for resale. However, dentists must pay tax to vendors if they will be using the whitening gel in their practice for compensation rather than reselling it. (State Tax News Vol. 33, No. 1, Spring 2004)