Growing up doesn't mean outgrowing the need for fluoride varnish

Just because insurance coverage for fluoride varnish often stops when a patient turns 18 doesn’t mean your fluoride varnish recommendations should stop. Erin Elliott, DDS, explains why and how you should talk to your adult patients about topical fluoride treatment.


Erin Elliott, DDS

People—specifically some patients—don’t make sense. Recently a patient came in for an emergency with a broken filling on No. 3. Just before I numbed him, he asked if I could look at numerous lower teeth on which he has noticed some brown stain along the gumline. He was concerned about cavities. This is how our exchange proceeded.

Me: Yes. You definitely have some stain. And unfortunately, one of these teeth does have decay. You will need a filling. Do you happen to chew tobacco?

Patient: Yes, but I move it around.

Me: Well, this will continue to happen. What I would suggest is a fluoride treatment of some sort to help strengthen the other areas, especially along the root surface. Cavities can happen faster and easier there.

Patient: What can I use that doesn’t have fluoride?

Me: Because you think fluoride is poison?

Patient: Yes.

Me: Um . . . and chew isn’t?

Now, I am not writing this to get into the fluoride debate, but it has led me to investigate how topical fluoride works and why varnish is the best form to suggest to patients. What I discovered is how important topical fluoride is, even in adults. I remember being so excited to turn 18—not so I could vote but so I could stop fluoride treatments at my dad’s dental office. I hated the trays, I hated sitting there with the suction, and I hated not eating or drinking for an hour. But little did I know how much we still need fluoride as we mature. (I don’t want to remind anyone that we’re getting older.)

A perfect storm of factors is needed for decay to begin: Streptococcus mutans, a low pH, a carbohydrate source, and tooth surface. If we can minimize risk factors, then we can prevent decay. Unfortunately, our exposure to carbohydrates does not end at the age of 18. Let’s focus on how we can make the tooth surface stronger, so even if we have an environment conducive to decay formation, the tooth will not cavitate.

A matrix of sorts makes up our teeth, and if we can make the matrix stronger, we can prevent its breakdown. Fluoride varnish has been found to decrease the incidence of decay and reverse incipient caries by strengthening the teeth and reducing the effects of the acid attack.1 Fluoride ions also disrupt cariogenic bacterial attacks. Fluoride varnish, in particular, reduces the amount of S. mutans by tenfold.2 Fluoride varnish has also been approved to treat dentinal hypersensitivity by occluding the dentinal tubules.3

Let’s look at the economics. Most dental insurance providers stop covering fluoride when patients turn 18, but again, its use is important to adults. Fluoride varnish has a cost-benefit ratio of 1.8 to 1, while fluoride rinse’s cost-benefit ratio is only 0.9 to 1.4 It is easy to apply and tastes good, and although it leaves a film for four to six hours, the benefits last months.

We explain to our adult patients that most likely they will have to pay the $30 out of pocket, and most are happy to pay to possibly prevent a more costly filling. The majority of my patients have xerostomia, clinical attachment loss, root exposure, and many restorations. This is one scientifically proven step that will prevent extensive dental work and patchwork while still boosting hygiene production. While the hygiene team and dentists see the benefits, the patients do too. If ingestion is a concern, the stickiness of the fluoride varnish makes it negligible.

When I do school visits to local middle schoolers, I focus on the “ingredients” it takes to form a cavity and explain that if we can take any of these away, they can prevent cavities. I tell them, “I would love to sit around and twiddle my thumbs, but instead I am doing way too many fillings.” And I’m not lying. If I can prevent cavities, I am happy, but most importantly, my patients are happy. I focus on proper hygiene, brushing, and flossing. I talk about the fact that mom and dad aren’t always there, making snack choices for them, so they need to choose wisely—but mom and dad often don’t make wise choices either. So if we can make the breakdown of enamel more difficult with a simple, cost-effective, and efficient fluoride varnish, then everyone wins.


1. Marinho VC, Higgins JP, Walsh T, Clarkson JE. Fluoride varnishes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2013;11(7):CD002279.

2. Jeevarathan J, Deepti A, Muthu MS, Rathna Prabhu V, Chamundeeswari GS. Effect of fluoride varnish on Streptococcus mutans counts in plaque of caries-free children using Dentocult SM strip [sic] mutans test: A randomized controlled triple blind study. J Indian Soc Pedod Prev Dent. 2007;25(4):157-163.

3. Gaffar A. Treating hypersensitivity with fluoride varnish. Compend Contin Educ Dent. 1998;19(11):1088-1090,1092,1094.

4. Sköld UM, Petersson LG, Birkhed D, Norlund A. Cost-analysis of school-based fluoride varnish and fluoride rinsing programs. Acta Odontol Scand. 2008;66(5):286-292.

Elliott Erin NewErin Elliott, DDS, is a practicing general dentist in Post Falls, Idaho, where she has successfully integrated dental sleep medicine into her busy general practice. She lectures extensively and leads a hands-on workshop focusing on practical strategies for successful implementation of sleep medicine into the general practice. She is an active member of the American Academy of Sleep Medicine and American Academy of Dental Sleep Medicine. She is a past president and diplomate of the American Sleep and Breathing Academy. Contact her directly at

More in Preventative and Hygiene