Can a dab of liquid really stop a cavity from growing? Everything you need to know about Silver Diamine Fluoride.

How does a cavity get there and what can be done to treat it?

A cavity is a hole in a tooth that forms when certain types of bacteria, that are found in the mouth, eat sugars and produce acid.  The acid takes mineral out of the tooth and causes it to soften.  If enough mineral is lost, the tooth surface starts to break down and the cavity is formed.   Decay is another word for the part of the tooth where the cavity is present.  This area is broken, soft/leathery, and houses the bacteria that cause the problem in the first place.

Cavities are usually treated by removing the decayed or infected portion of the tooth.  This “rotten” part of the tooth is removed with a traditional “drill” and usually requires the tooth to be numb for this procedure to be completed comfortably.  Then a dental filling is placed in the hole left behind to strengthen the tooth and prevent further breakdown or re-infection, while restoring function for eating, speaking, and general esthetics.  This can be an unpleasant experience for some people.    But what if the drill and needle weren’t necessary?

Silver diamine fluoride, also known as SDF, can be the answer in some situations.

What is SDF?

Silver diamine fluoride (SDF) is a liquid substance that is made up of four parts: silver, water, fluoride, and ammonia.  It is applied directly to the decayed tooth surface with either a fuzzy little brush or a thick, braided string of floss.  The cool part is that studies show it can stop cavities from growing and can even prevent other cavities from forming.

While SDF has been used outside the United States for decades, it has more recently made a ripple in the United States dental community.  It was approved by the FDA in 2014 and in 2017 the American Academy of Pediatric Dentistry (AAPD) updated their guidelines to include SDF as a recommended treatment of cavities in children and adolescents.  In 2018, the American Dental Association noted it as an effective treatment for older adults as well.

How does it work?

The silver portion of the mixture is what kills the bacteria that cause cavities to form in the first place.  In this process the silver ions (particles) attack the active bacteria and also imbed themselves in pores in outer tooth structure and block these holes from further bacterial activity.  They can protect the surface from future bacterial attacks.  The fluoride also becomes part of the tooth to strengthen that outer layer that had softened and prevent future cavities from forming in the same place.

In most cases SDF is applied and then re-applied at a follow-up appointment 2-4 weeks after the first application.  It then may require re-application every 6-12 months to remain effective in preventing bacterial activity.  If there is an actual hole (late stage cavity) in the tooth that collects food or is difficult to clean, it can be filled via a different filling technique known as the “SMART” restoration technique that does not require anesthetic (numbing).

Is SDF different than sealants or in-office topical fluoride application?

Yes, SDF is different than both of these procedures.  Sealants prevent cavities from forming by coating the deep grooves of the teeth.  This prevents food and bacteria from getting into these areas.  If sealants are not placed, it can be difficult to clean the teeth entirely and cavities will form in the grooves on the biting surface or sides of the tooth.

Fluoride Varnish is applied to keep the enamel (the outer tooth layer) hard and strong to help resist cavities from forming.  Fluoride makes the tooth more resistant to acid and softening.  It cannot stop a cavity from progressing once it is already present.  As mentioned above, SDF uses silver to kill bacteria and stop a cavity from progressing and then the fluoride allows the tooth to re-harden to its usual strength.

Is it safe?  What are the side effects of SDF?

When SDF is applied to a tooth surface, it will turn the portions of the tooth that are infected or decayed BLACK but leave any healthy tooth structure its natural color.  The portions of the tooth that turn black will remain black permanently.  This is the part of the tooth that would have been removed with a traditional “drill” technique.  If SDF is not applied carefully or if there is movement from the patient during the procedure (which only lasts 1 minute), there is the possibility of staining the surrounding tissue like the gums, tongue, cheek or lips.  These stains are more like a temporary tattoo and only last 1-2 weeks.  During the application or for the first 24 hours, the patient may notice a metallic taste or an increase in sensitivity to cold or sweets on the tooth in question but this resolves within the first day.  In fact SDF is also used as a hypersensitivity treatment for teeth with and without cavities.

SDF is very safe.  It is applied to only small isolated areas and is either rinsed or dabbed off after application.  None of the product is swallowed and because application is so quick and direct there is little chance for the liquid to be placed in unintended areas or to spread.   The fluoride in 1 drop of SDF (which can treat up to five teeth) is very minimal, the equivalent of a properly fluoridated liter of water.  This is less than you would find in a topical fluoride. Silver nitrate has been safely used in dentistry and medicine since the 1800’s without any reported incidence.  Silver is used to in eye drops on infants to prevent eye infections and to treat burns and skin infections.  It is considered safe for medicinal use.

Who is a good candidate for SDF treatment?

Since there are no drills, no needles, no pain and it is a relatively quick procedure, SDF is especially useful in the treatment of young children and people with special needs that have trouble sitting through traditional treatment.  It can also be useful in treating cancer patients and the elderly, who are more prone to cavities due to the use of multiple medications or radiation which can result in severe dry mouth.  It can also be used to “put out the fire” in patients with large amounts of decay, or extensive treatment needs that take extra time and resources to complete.

As a newer treatment option, not all dental offices offer SDF.  Dr. Kelly started working with SDF back in 2017 and has completed 30+ hours of continuing education on the use of this specific therapy.  She has completed countless successful cases both at Children’s Hospital of Wisconsin and at Generations Dental.  This experience helps her to sort out what cases will be most successful with this type of treatment.  SDF may not be right for everyone.  If there is an abscess or the decay is too severe, SDF cannot be used.  Also, it may not be ideal for tooth surfaces that show in an adult smile due to the permanent dark stain that is left behind (though sometimes this can be worked around).  Some teeth treated with SDF will require a separate final treatment at a later date.   It should be noted that research shows that SDF treatment is effective in 80% of cases.  This means that even with good cooperation and a properly timed application sequence 20% of cavities treated with SDF will continue to grow.  However, with adjunct therapies such as diet modification or the use of different over the counter or prescription oral care products we can often achieve a higher success rate than the 80% listed above.   Although SDF is not a “silver bullet” that is 100% effective, it is a wonderful tool in our tool box that offers a conservative, pain free option for the treatment of cavities.

In our office, we use this treatment regularly on kids, special needs patients, elderly patients, and around crowns and fillings, in deep grooves, and on root surfaces of adult teeth.  If you would like to learn more about this treatment and if it would work in your mouth, give us a call.  We would love to offer a pain free option to return your mouth to health.