What is Fluoride and how does it help our teeth?

Fluoride comes from the element fluorine.  Fluorine is a natural element found in the earth’s crust, in water and air.  Fluoride is safe and is proven to help us maintain our teeth in many ways, all of which are equally important. It helps prevent tooth decay by decreasing the effect of “decay causing” oral bacteria, by becoming incorporated into tooth enamel and strengthening it, and by remineralizing tooth enamel that is in the early stages of break down.

Enamel is the hard covering of the teeth, the surface we brush to keep free of plaque or bacteria build-up. When we eat sugars, we are feeding oral bacteria and they begin to produce acids that break down our teeth, or the enamel.  If the acid is neutralized, the process of demineralization of the enamel will stop.  Fluoride helps prevent the process of decay by slowing down the acid production of bacteria, and encouraging remineralization of enamel.  When this enamel remineralizes, it becomes stronger and more resistant to decay. It is important to note that once demineralization of enamel has occurred and it reaches the second internal layer of the tooth, the dentin, fluoride can not “fix” or remineralize the cavity.

Fluoride can be administered in two ways, systemically or topically.  In children up to age 7, systemic, (ingested,) fluoride is given so that it becomes incorporated into the developing enamel, making it stronger and more resistant to decay.  Topical Fluoride helps in all of the ways listed above and is applied directly to the teeth.  There is discussion that the most effective administration of Fluoride is by topical application.

Methods in which we receive fluoride

For patients that live in an area where the water source is fluoridated, it is taken into their system every time they drink tap water.  Fluoridated water helps children with developing teeth by providing fluoride that becomes incorporated into developing enamel and making it stronger as it is made.  It helps all patients by becoming part of the saliva that coats the teeth.  Saliva with fluoride helps to neutralize the bacteria in the plaque, and aids in remineralization of the enamel.  Fluoridated water also provides a topical effect of fluoride by the water itself coming in contact with teeth.

In areas that do not fluoridate the water supply, children can be given fluoride supplements during tooth development.  These are small tablets that are chewed and swallowed.  By chewing and swallowing, the child is providing fluoride in a topical and systemic manner. With this being said, later in this paper we will discuss the risks of too much fluoride. Because of the risks associated with too much fluoride exposure during tooth development, it is important to discuss supplementation with your pediatrician or dentist.

Fluoride is also found in toothpaste.  Keep in mind that there are also toothpastes made that do not contain fluoride.  Due to its effect in decreasing tooth decay, it is important that fluoridated toothpaste is used for brushing teeth.  It is also important to make sure that children are not receiving too much fluoridated toothpaste.  Children who can not rinse and spit effectively should not be using toothpaste with fluoride.  TheAmericanAcademyof Pediatric Dentistry suggests that a smear of toothpaste be used for children who are less than 2 and can rinse and spit to some degree. This is recommended for children growing up in non fluoridated water areas.  Fluoridated toothpaste should not be used until age 2-3 if the child is growing up with a fluoridated water source. Children ages 2-5 can use a pea size amount of toothpaste to brush with, again, being sure that they rinse and spit after brushing.  For children lees than age 6 it is important to limit tooth brushing to 2 times a day with fluoridated toothpaste and for all teeth brushing to be supervised by a parent or guardian.

There are many things to take into consideration when recommending fluoridated toothpaste for children.  The Center for Disease Control and Prevention suggests that for children less than age 2, other sources of fluoride ingestion need to be considered before the parent decides to use fluoridated toothpaste.  We will discuss the risks of too much fluoride during tooth development later in this paper.

Children in fluoridated and non fluoridated areas should focus on low dose, high frequency approaches to fluoride exposure.  Twice daily use of fluoridated toothpaste coupled with professional application of topical fluoride gel, foam or varnish is a great place to start in preventing tooth decay.  Other fluoride regimens can be recommended by your health care professional once a caries risk assessment is done.

Recommendations for Fl supplementation

It is very difficult to provide a flat out rule for fluoride supplementation that will cover all patients.  For adults who are living in areas with fluoridated water, using fluoride toothpaste and receiving fluoride treatment twice a year during your dental visit is sufficient if you are not prone to decay.  If you are prone to decay, you will want to add a fluoride mouth rinse o prescription strength fluoride toothpaste to your daily regiment of oral care.

For adults in non fluoridated areas, using fluoride toothpaste, receiving a fluoride treatment at your biyearly dental visit and a fluoride mouth rinse will keep decay at bay.

Fluoride supplementation is not so cut and dry for the pediatric patient growing up in a non-fluoridated area.  Due to the fact that children have teeth developing, we want to be sure that enough fluoride is incorporated into the developing teeth to help strengthen them, but not so much to cause fluorosis.  Fluorosis is a condition in which the teeth have too much fluoride and they become spotted, pitted, and/or stained.  Children who are growing up in an area where the water source has fluoride, can begin brushing with a small amount of fluoridated toothpaste after age 2 and receive fluoride treatment from their dentist twice a year during their dental visit.  Children in non fluoridated areas need to have evaluation of their fluoride contact prior to any fluoride supplementation. The chart below shows the basic rules that are followed for supplementation with systemic fluoride.

Water Fluoride Concentration in parts per million

Age                                         less than 0.3               0.3-0.6             greater than 0.6

 Birth to 6 months                            0                                    0                           0

 6 months to 3 years                      .25                                    0                           0

 3 years to 6 years                           .50                                 .25                         0

 6-16 years                                        1.00                              .50                          0

With this chart to follow, parents must take into consideration all forms of possible fluoride exposure, such as if the child is in a daycare/ school setting where the water is fluoridated or what their home water source is and what amount of natural fluoride may be in their water source. All forms of possible fluoride exposure must be determined before supplementation is determined.  It is helpful for your child’s physician or dentist to have this information prior to describing supplements or giving fluoride usage instructions. Other factors that your health care provider will consider are the risk of caries that a particular child may have.

It is important to note that fluoride does not cross the placenta or breast milk so fluoride supplements are not recommended pre or post natal.

Precautions for Fl intake

Just like anything, fluoride beyond appropriate dosing can have adverse effects.  The development of fluorosis can occur if a person is exposed to too much fluoride.  This condition can actually increase susceptibility to tooth decay as well as having effects on the rest of the bones.

The possibility of fluorosis is the reason that the amount of fluoride in the drinking water be monitored carefully, whether it is being added by the water company or occurs naturally.  It is also the reason that children need to be supervised while using fluoridated toothpaste and why all sources of fluoride exposure needs to be determined prior to supplements being prescribed.

Children ages 0-6 are susceptible to developing fluorosis because their permanent teeth are developing.  Dental fluorosis can not occur after 7-8 years of age due to the fact that the permanent teeth are already developed even though they are not all erupted.


The take home from this write up is that our teeth need fluoride.  It is safe and effective in decreasing tooth decay in all age groups when teeth are exposed to it topically. Given systemically, it also helps strengthen teeth during permanent tooth development.  Parents must be very aware of the sources of fluoride intake prior to requesting a fluoride supplement from their child’s health care provider.  Just like anything else, too much of a good thing can have adverse effects.

Dr. Bloomquist, and all of us at SoundBridge Center for Dental Arts are happy to answer any questions you may have about fluoride and its role in preventing tooth decay.