Tooth enamel is the hardest part of the human body. It protects the teeth against strong chewing forces, which can vary between 300 and 600 Newtons in healthy people. The enamel also gives the teeth their aesthetic color.
The enamel itself consists of tightly packed crystals of hydroxyl apatite (consisting of calcium, phosphate and hydroxyl ions). Saliva is rich in the very minerals which form the enamel. Thus a reversible chemical action sets in when saliva is wetting the teeth. Apatite tends to pass into saliva (demineralization), and apatite in the saliva tends to pass to the tooth surface (remineralization). At the normal pH (about 7) apatite concentration in saliva is sufficient to maintain a balance, and enamel is preserved.
If plaque is present, bacteria found in plaque act with sugars and carbohydrates to produce acid. This lowers the pH around the plaque region, and the balance of the chemical process shifts in favor of demineralization. This tends to make the enamel weak and porous, and can cause white spots on the teeth. Over a period of time this process results in development of cavities.
Fluoride Promotes Remineralization
If salts containing fluoride are eaten, fluoride ions will increase their concentration in the saliva. This will lower the pH, and tilt the balance of the chemical process in favor of remineralization.
Fluoride Reduces Demineralization
Further, fluoride ions will replace hydroxyl (OH-) ions in the apatite in the enamel, and form fluorapatite. Fluorapatite crystals form a surface layer on the enamel. The critical pH, above which demineralization will be favored, is around 5.5 for hydroxyapatite and around 4.5 for fluorapatite. Thus, presence of fluorapatite in the surface layer of the enamel will make the enamel more resistant to demineralization due to acid, and hence, reduce the chance of caries.
Fluoride Can Discourage Bacteria Action
Fluoride cannot penetrate the cell wall of bacteria in ionic form. However, in the presence of acid, hydrofluoric acid molecules are formed, which can easily penetrate the bacterial cell wall. Once inside, the acid dissociates to hydrogen and fluoride ions. The fluoride ions have the ability to retard bacterial activity. The fact that fluoride is more effective against bacteria in an acid environment is significant because it is the bacteria which create the acid. Fluoride is thus a very desirable substance for health of one’s teeth.
How to Provide Fluoride
Fluoride can be provided to a patient in various manners, namely through natural food items, as supplements, and applied topically. This is explained below.
Naturally Through Foods
Certain food items are rich in fluorides. Compared on per calorie basis, pickles, cucumber, and dill top the table for fluoride content, followed by grape juice, spinach, tomato, apples, carrots, citrus juices, and most vegetables.
Fluoride intake is best supplemented through a community water supply. The recommended level of fluoride in drinking water is 0.7 parts per million (ppm). It is to be noted that excess fluoride content may cause fluorosis. Children in development stage are particularly susceptible to dental fluorosis, a condition in which causes roughening and pitting of the enamel, in addition to stains that are permanent, and are not removed even after bleaching.
Other than fluoridated water, fluoride supplement drugs are available in liquid or tablet form. Such drugs are to be prescribed by the dentist or the physician. Supplements will normally not be prescribed if the community water is being properly fluoridated. The dentist will see that the total intake of fluoride will not exceed a safe level.
Supplemental fluoride is normally given at ages between 6 months and sixteen years.
Fluoride may be directly applied through the use of fluoridated tooth pastes, gels, mouth wash, or special varnishes. Topical fluoride treatment may also be given by the dentist in his office.
Controversy has surrounded fluoride use in public water systems and administration in children for over a decade. Yet all the data discussed above far outweighs any reasons people fight against fluoride use. We highly recommend it. If you have further questions, feel free to give our Arlington office a call or chat us up at your next dental visit.