Basic success of caries prevention: fluoride
- Benefits?
- Goal?
Fluoride
- Benefits: reduce caries, but with excessive amount in early stages of development
can form dental fluorosis
- Goal: maximize anticaries benefits, while minimizing the risk of dental fluorosis
3 mechanisms of action of fluoride
- fluoride is present when acids are produced –> will go into the tooth at the same time or before the acid.
- Stick or absorb at the surface of tiny crystals of the tooth and stop acid
from dissolving the crystals, acts like a bodyguard. - If fluoride is present when acid is neutralized –> fluoride together with calcium
and phosphate from saliva go into the tooth and remineralize or grow a new surface of crystals that is much more resistant
- *extremely important - Fluoride if present among the bacteria when producing acid –> fluoride gets taken into the bacteria, slows them down or kills them.
Reduced Demineralization and Enhanced Remineralization
• pH 5.5 or below - Hydroxyapatite starts to dissolve
• pH 4.5 or below - Fluorapatite starts to dissolve
• pH above 5.5 - fluoride enhances enamel-dentin remineralization
• Biofilm pH between 4.5 - 5.5 - fluoride available in low conc, fluorapatite
forms on surface of layers of enamel even if hydroxyapatite
dissolves
• Overall effect: reduce dental demineralization
Antimicrobial Qualities
- Inhibit bacterial enzyme enolase (interferes with production of PEP)
- PEP = source of energy for bacteria and needed for sugar uptake
Fluorosis
occurs with exposure of abnormally high conc of fluoride during early stages of tooth development –> can lead to hypo mineralization (gives chalky white lines/stains)
Systemic Fluoride Delivery
Goal: promote remineralization and reducing demineralization o Water fluoridation: primary systemic method
o Salt fluoridation: common in other parts of the world
o Milk fluoridation: Implemented in other countries
o Fluoride supplements: CDC and ADA currently recommend oral fluoride supplements used for only high-risk children in nonfluorinated areas
Topical Fluoride Delivery
toothpastes, gels, varnishes, paint-on formulation and mouth rinses that come into contact with tooth surface
Fluoride mouth rinses
Fluoride mouth rinses:
o Some may need a prescription if have higher conc
o Can contain antimicrobial ingredients, many have little to no caries-reducing effects or have not been studied for their anti-caries effects
Professional delivery of fluoride
- Given to patient with high risk of caries and if other dental care measures (good oral hygiene) are not working or being followed.
- High conc of ppm and recommended 2x/yr
Professional slow-release fluoride - currently being developed.
Added to composite and amalgam fillings, with goal to prevent secondary caries and help remineralize caries in adjacent surfaces.
Fluoride is incorporated into
the inorganic part of enamel, the inorganic phase, by substitution for either hydroxyl ions or carbonate ions within the apatite lattice.
Fluoride ingested –>
distributed from plasma to all tissues and organs of body –> gradually becomes incorporated into the crystal lattice structure of teeth in the form of fluorapatite.
Fluoride concentration
High on enamel layer
Remains constant at enamel-dentin junction
Increases inside the dentin and increases deeper into the tooth
Fluoride DOES NOT have
hemostatic mechanism to maintain the body, so regular exposure to maintain fluoride conc in enamel, saliva, and biofilm on dental surfaces
what are the common forms of toothpaste in the U.S.
sodium fluoride, sodium monofluorophosphate (SMFP), and stannous fluoride (SnF2)
Toothpastes can include
abrasives to clean teeth, binders to prevent
separation of ingredients, coloring for visual appeal, buffers to maintain product stability, flavorings, and surfactants
Fluoride dentifrices use
some combos to target different goals of the patient (plaque and gingivitis protection, tartar control, whitening, sensitivity protection, erosion protection)
In summary, dental professionals should recommend to their patients
- An accredited fluoride toothpaste.
- A toothpaste with an appropriate fluoride concentration after assessing potential caries risk and overall fluoride exposure.
- To brush twice daily; once at night and once more at another time during the day, preferably around a mealtime.
- That children be given a minimum amount of toothpaste and be supervised when brushing.
Brushing behavior should be
2x/day = 20% to 30% lower likelihood than brushing one or less daily.
Rinsing behavior
if use a cup to rinse with water after brushing –> 20% more caries than those who use their hands because with the cup more fluoride is washed away
