Transcript FLUORIDES - University of Kentucky

FLUORIDES
What is fluoride?
• Fluoride is the ionic form of the element fluorine.
• It is negatively charged and will not remain as a free
element.
• Fluoride has a high affinity for calcium.
– It is, therefore, very compatible with teeth and bone.
Mechanisms of Action
• Topical
• Systemic
• Antibacterial
Mechanisms of Action
•
Topical
–
–
inhibits demineralization
promotes remineralization
Mechanisms of Action
• Fluoride’s role in remineralization
– When bacteria metabolize carbohydrate and produce acid,
fluoride is released from dental plaque in response to lower
pH levels at the tooth interface (Tatevossian, 1990).
– To be more acid resistant and contain more fluoride and
less carbonate, the demineralized enamel crystal structure
takes up released plaque fluoride and salivary fluoride
along with calcium phosphate.
Mechanisms of Action
•
•
•
•
•
•
The pH in the oral cavity falls within
seconds of ingestion of dietary sugars.
The pH can stay low for up to two
hours.
Low pH leads to demineralization of
the tooth structure.
When pH returns to normal/neutral,
remineralization can occur.
The original mineral apatite structure
of teeth is rich in carbonate, has
relatively little fluoride and is
relatively soluble.
Cycles of partial demineralization and
remineralization in a fluoride-rich
environment can create fluoride-rich,
low-carbonate apatite, which is up to
10X less soluble than the original
apatite structure.
Remineralization
Demineralization
Demineralization
Remineralization
Mechanisms of Action
• Systemic
– improves enamel crystallinity
– reduces acid solubility
– improves tooth morphology (controversial)
Mechanisms of Action
• Several studies have reported that teeth formed in fluoridated
communities or exposed to fluoride supplements preeruptively tend to be smaller and have shallower pits and
fissures than teeth formed in non-fluoridated communities or
not exposed to pre-eruptive fluoride supplements (Lovius et al,
1969; Simpson, et al, 1969; Aasenden, et al, 1974).
• These researchers believe that even if the differences are small
and do not entirely explain lower caries prevalence, the very
fact that measurable alterations in tooth morphology occur
when there is pre-eruptive exposure to fluoride indicates that
there must be some effect from exposure to fluoride during
tooth development.
Mechanisms of Action
• Antibacterial
– concentrates in plaque
– disrupts enzyme systems
• Fluoride inhibits bacterial metabolization of carbohydrates to
produce acid and affects the bacterial production of adhesive
polysaccharides (Hamilton, 1990).
• When fluoride is constantly present, mutans Streptococci produce
less acid (Bowden, 1990).
Pre-eruptive vs. Post-eruptive Fluoride
• Pre-eruptive fluoride exposure = systemic fluoride
exposure
• Post-eruptive fluoride exposure = topical fluoride
exposure
According to the CDC 2001 Recommendations for Using
Fluoride to Prevent and Control Dental Caries in the United
States (at the website), “. . .laboratory and epidemiologic
research. . .indicates that fluoride’s predominant effect is posteruptive and topical.”
HOWEVER. . .
• Clinical epidemiologic data demonstrate both pre- and posteruptive caries-preventive benefits to teeth from fluoride.
A recent report showed that pre-eruptive exposure to fluoride
in Australian children 6 to 15 years old was required for a
caries-prevention effect in first permanent molars and that
exposure to fluoride after eruption alone did not alter caries
level significantly (Singh, et al, 2003).
Maximal caries-preventive effects of fluoridated water were
achieved by high pre- and post-eruption exposure.
Summary of Anti-Caries Activity of Fluoride
1.
2.
3.
4.
5.
Fluoride prevents demineralization.
Fluoride enhances remineralization.
Fluoride alters the action of plaque bacteria.
Fluoride aids in posteruptive maturation of enamel.
Fluoride reduces enamel solubility.
Fluoride
--A Brief Glimpse into History-• Fluoride’s ability to inhibit or even reverse the initiation and
progression of dental caries is well documented.
• The first use of adjusted fluoride levels in water supplies for
caries control began in 1945 and 1946 in the United States and
Canada.
• The first field study occurred in four pairs of cities—Grand
Rapids and Muskegon, MI; Newburgh and Kingston, NY;
Evanston and Oak Park, IL, and Brantford and Sarnial, Ontario
Canada.
• Sequential cross-sectional surveys were conducted over the
next 13 to 15 years.
Fluoride
--A Brief Glimpse into History-• The findings included:
– a reduction in caries of 50 to 70% in children with fluoridated water
supplies.
• As a result, in the 1940s, 1950s, and again in 1962, the U.S.
Public Health Service (PHS) developed recommendations
regarding fluoride concentrations in public water supplies.
• The recommendations occurred after patterns of water
fluoridation and caries experience across different climates and
geographic regions in the U.S. were studied through
epidemiologic investigations.
• Depending on climate, the recommended range of water
fluoridation varied from 0.7 to 1.2 parts per million (ppm).
Fluoride
--A Brief Glimpse into History-• The success of water fluoridation in preventing and controlling
dental caries led to the development of fluoride-containing
products, including toothpaste, mouth rinse, dietary
supplements, and professionally applied or prescribed gel,
foam, or varnish.
• In addition, processed beverages, which constitute an
increasing proportion of the diets of many U.S. residents, and
food can contain small amounts of fluoride, especially if they
are processed with fluoridated water.
Fluoride
--A Brief Glimpse into History-• Benefits of fluoride
– Fluoride helps to prevent tooth decay.
• People with non-fluoridated water supplies continue to demonstrate higher
rates of decay.
• A 15 year landmark study in Grand Rapids, MI showed that children who
had fluoridated water from birth had a 50 to 63% decrease in tooth decay.
• In 1993, the results of 113 studies in 23 countries were compiled and
analyzed. The review included 66 studies in primary teeth and 86 studies
in permanent teeth. Together the decay reductions were:
» 40 to 49% for primary teeth
» 50 to 59% for permanent teeth
Fluoride
--A Brief Glimpse into History-A comprehensive analysis of the 50 year history of community
water fluoridation in the U.S. demonstrated that the inverse
relationship between higher fluoride concentration in drinking
water and lower levels of dental decay continues to be true
today.
Fluoride
--A Brief Glimpse into History-• Water fluoridation is cost
effective.
• Per person, it costs on
average $ .50-1.00 per year.
• Water fluoridation is
especially beneficial for low
socioeconomic communities
where there is a
disproportionate burden of
decay and less access to
dental care and other
fluoride sources.
• Fluoride is safe and effective.
• Nearly 100 national and
international organizations
including the ADA, USPHS,
AMA, APA, AFP, IADR, the
National PTA, the ACS, and
WHO endorse optimal
fluoridation of community water.
• The ADA has endorsed water
fluoridation as safe and effective
for over 40 years.
Water Fluoridation
Surgeon General David Satcher wrote in his report, Oral
Health in America,
“Community water fluoridation is safe and effective in
preventing dental caries in both children and adults. Water
fluoridation benefits all residents served by community water
supplies regardless of their social or economic status.”
Status of Community Water Fluoridation in
the United Sates
• Fluoridated water is currently provided in 10,500 U.S. communities.
• 145 million U.S. residents currently benefit from fluoridation.
• 62% of the population served by community water system are provided
optimum levels of fluoride.
• In 2000, a total of 38 states and the District of Columbia provided access to
fluoridated water supplies to greater than 50% of their population.
• Kentucky was one of the first states to mandate that all community water
supplies had to be fluoridated. Kentucky continues to be a leader in the
percentage of the public water supplies fluoridated.
*Centers for Disease Control and Prevention, Division of Oral Health Fluoridation Census, 1992
and 2000.
Fluoride
--Other Sources-• Types of fluorides
– In the United States, there are three types of fluorides
approved by the FDA as safe and effective for use in
dentifrices:
• Sodium fluoride (for use in paste, must be bound to another
element or it will bind to the abrasive ingredient)
• Sodium monofluorophosphate (holds fluoride in complex form and
is released when exposed to phosphatase enzyme in the mouth)
• Stannous fluoride (was the first used in dentifrice, was previously
difficult to stabilize, has gingivitis-reduction properties, but has an
astringent taste and potential staining)
Fluoride
--Other Sources-• Fluorides for Professional Use
– FDA approved for professional use:
• Acidulated phosphate fluoride (APF) with 1.23% (12,300 ppm)
Fluoride
--Other Sources-• Fluorides for Professional Use (continued)
– FDA approved for professional use:
• APF
• Neutral sodium fluoride (NaFl) with 2% (9,000 ppm)
Fluoride
--Other Sources-• Fluorides for Professional Use (continued)
– FDA approved for professional use:
• APF
• NaFl
• Stannous fluoride (SnFl) with 8% (not used routinely for topical
semi-annual applications)
Fluoride
--Other Sources-• Fluoride Varnish
– There is strong evidence for the use of fluoride varnish for
caries control of permanent teeth, but the evidence for
primary teeth is, while promising, inconsistent and
incomplete (IOM Report, 2000).
– NaFl varnish delivers 2.26% fluoride (22,600 ppm), the
strongest concentration of fluoride delivered.
– Application stays on tooth surface 4 to 6 hours after
application (product is purposely colored to detect
presence)
Fluoride
--Other Sources-• Fluoride Varnish (continued)
– Effectiveness thought to be the result of substantial increase
in fluorine content of the tooth surface and subsurface
enamel
– Fluoride varnish has been used since late 1960 in Europe
and Canada as a primary preventive agent, with as much as
a 75% reduction in decay (GoranKock, 1975).
– Fluoride in varnish also gradually dissolves into the plaque,
saliva, and enamel providing bacteriocidal, bacteriostatic,
and remineralizing effects (Nelson, 1984).
Fluoride
--Other Sources-• Fluoride Varnish (continued)
– No toxic effects were found in the blood plasma levels in preschool and
school children after treatment with varnish. The use of varnishes is,
therefore, safer than gels with small children (Ekstrand, 1981).
Children younger than six years of age tend to swallow 30 to 50% of
gel products (LeCompte, 1987).
– The FDA has cleared fluoride varnish as a cavity liner or root
desensitizer. All other uses are currently considered “off-label”!
– After 2 ½ years, fluoride varnish resulted in a higher percentage of
caries reduction than 2% NaFl solution or 1.23% APF gel (Tewart,
2000).
Fluoride
--Other Sources-• Which varnish do we
currently use at UKCD?
CavityShield
Fluoride in Prophy Paste
• Contains 4,000 to 20,000 ppm
• May replace the concentration of fluoride removed by
polishing, but does not adequately substitute for
fluoride gel or varnish in treating high risk caries
patients (Stookey, 1995).
Fluoride
--Other Sources-• Fluoride for Home Use
– Home delivery modalities
• Neutral sodium fluoride
– .05% (225 ppm) –rinse
– .2% (1,000 ppm) –Rx rinse
– 1,000 – 1,500 ppm –Regular over the counter paste
– 1.1% (5,000 ppm) –Rx paste
» Example: Prevident 5000
Fluoride
--Other Sources-• Fluoride for Home Use (continued)
– Home delivery modalities
• Acidulated phosphate fluoride
– .044% (1,100 ppm) –rinse
– 5,000 ppm –Rx gel
• Stannous fluoride
– 3,000 ppm –Rx gel
– .63% --Rx rinse
Fluoride
--Other Sources-• Fluoride Dentifrices
– Best topical application for compliance
– Ingestion: 0.2 to 0.3 mg can be swallowed by pre-school
aged children when brushing twice a day
– Recommendations/instructions for use
•
•
•
•
Fluoride dentifrice (>90% use in U.S.)
Very small, pea-sized amount in pre-school aged children
Parents must supervise small children
Rinse and expectorate following brushing
Comments on the Efficacy of Fluoride
• The greatest preventive benefits are gained at fluoride levels
that are greater than or equal to 1,500 ppm of NaFl with
frequent applications (Vernon, 1992).
• As little as 1 to 3 ppm affects acid production.
– Bacteriostatic at 250 ppm
– Bacteriocidal at 1000 ppm (Van Leuveren, 1990)
• Use of regimens according to their individual risk level yields
greater probability of success and better cost effectiveness than
applying identical treatments to all patients independent of risk
levels (Anusavice, 2001).
• Due to fluoridated water and fluoride toothpaste, the salivary
level of fluoride between brushing is thought to be 0.2 to 0.8
ppm (Duckwork, 1991).
Comments on the Efficacy of Fluoride
• For children with low risk of dental caries (reference risk assessment
criteria previously discussed) “professional topical fluoride
applications are not likely to be cost effective.” (Consensus
conference of fluoride usage—see website for link.)
• Topical fluorides can be expected to prevent 0.03-0.26 decayed
surfaces per year, but only if applied every six months.
• Topical fluorides are not recommended as a routine therapy for
children at low risk for caries who live in a fluoridated
community, due to their relatively low cost-benefit
effectiveness.
• Topical fluorides have their greatest effect on smooth surface
enamel. Their impact on caries prevention is significantly less on
fissures due to the impaction of plaque in fissures. The clinical
relevance of this is that it is critically important that in applying
a topical fluoride it be carried inter-proximally (to the most
susceptible smooth surfaces of teeth) with dental floss.
Fluoride and Anticipatory Guidance
for the Pediatric Dental Patient
• Early childhood appointments provide a stage for
discussion of family water use, fluoride-vitamin
combinations, introduction and prudent use of
fluoridated dentifrice and the inappropriateness of
mouth rinses for the very young.
• Timely patient education prior to the high fluorosis
risk period between 22 and 36 months of age may
minimize inappropriate fluoride use and fluorosis
(Den Besten, 1994).
Fluoride and Anticipatory Guidance
for the Pediatric Dental Patient
• In evaluating daily fluoride exposures for young children, the
use of filters that may remove fluoride from city and well
water must be addressed.
• Water testing services exist at the Kentucky State Department
of Health.
• Most commercial infant water contains 1 ppm of fluoride.
• Other bottled water brands may have fluoride concentrations
in varying amounts; the information should be verified by
documentation requests to the particular bottling company.
Fluoride and Anticipatory Guidance
for the Pediatric Dental Patient
• Core components of anticipatory guidance for the
very young should include:
– Encouragement for use of optimally fluoridated water
– Minimal dentifrice per use
– Professional supplementation subsequent to water testing
Fluoride Supplementation Schedule
Fluoride Content of Water
Adapted from American Academy of Pediatric Dentistry Handbook, 1999
AGE
<0.3 ppm
0.3 – 0.6 ppm
>0.6 ppm
6 months – 3 years
0.25 mg/day
--
--
3 years – 6 years
0.50 mg/day
0.25 mg/day
--
6 years – 16 years
1.00 mg/day
0.50 mg/day
--
Prescribing Fluoride Supplements
• Select doses: age, water F status (based on water
analysis)
• Select supplement: drops, tablets, lozenge, rinse
• Write prescription: specific directions; maximize 120
mg per Rx
• Educate parent and patient
Pertinent Issues
• Dose/frequency—effectiveness (low dose, high
frequency is current “best” use of F)
• Bottled water (variable fluoride content, may vary
seasonally and with manufacturer)
• Filtration systems: point of use system can reduce
fluoride
• Prenatal use (not shown effective)
• Formula (0.1 – 0.3 ppm on average for both soy and
milk-based formulas)
Fluoride Supplementation Prescriptions
--Examples-• 8-Month-Old Residing in a Fluoride-Deficient Area
Rx: Sodium fluoride solution (0.125 mg F/drop)
Disp.: 40 mg
Sig.: Before bed time dispense 2 drops of liquid in
mouth
• 6-Year-Old Residing in a Fluoride-Deficient Area
Rx: Sodium fluoride tablets (1 mg F/tablet)
Disp.: 120 tablets
Sig.: Before bed time after a thorough brushing,
chew one tablet, swish, and swallow
Fluoride Supplementation Prescriptions
--Examples-• High Caries Risk Patient
Rx: NaF Gel (0.5% F)
Disp.: (varies depending on product)
Sig.: Brush on fluoride gel once/twice daily instead
of toothpaste
Example: Prevident 5000
The Fluorosis Issue
• Fluorosis is a permanent intrinsic white-to-brown discoloration
of enamel.
• Increase in prevalence due to ambient fluoride.
• Sources of ingested fluoride
– Diet/ “halo” effect from foods, beverages
– Dentifrice consumption
– Previous supplementation schedules based on presumed lower fluoride
intake
– Inappropriate prescriptions for children already receiving adequate
fluoride
• Measured by Dean’s Index (mild to severe)
Fluoride Toxicity
• Symptoms of overdose
– GI (nausea and vomiting)
– CNS
• Death in 4 hours
• Probably toxic dose =
• Certainly lethal dose =
5 mg F/kg
16 – 32 mg F/kg (Hodge
and Smith)
15 mg F/kg (Whitford)
Fluoride Toxicity
• Treatment (Augenstein et al)
– Determine child’s weight and estimate amount ingested
– <8 mg F/kg: give milk, observe > 6 hours, refer if
symptoms develop
– >8 mg F/kg: give syrup of ipecac, followed by milk; refer
immediately
– Unknown dose: if asymptomatic treat as <8 mg F/kg, if
symptomatic (already vomited) give milk, refer
immediately
– Contact poison control center: gastric lavage, IV calcium
gluconate
Guidelines for Calculating the Quantity and
Concentration of Fluoride
Ion in Fluoride Compounds
Introduction
--Why do we calculate the Fluoride Ion?-•
Fluoride by “nature” is a very active element. Its
active nature will not allow it to be found in its pure
form. As a result, fluoride combines with other
elements to form fluoride compounds. We have to
calculate the amount of fluoride ion in each
compound in order to:
1. Compare the strength of different fluoride compounds by
knowing the concentration of fluoride ion in each
compound.
2. Calculate the exact amount (“quantity”) of fluoride ion
ingested in case of accidental ingestion of any fluoride
compound.
--What are the Risks of Ingesting More than the
Recommended Dose of Fluoride?-• In contrast to the desirable anti-cariogenic effect of fluoride, it
is also a toxic substance. Acute ingestion of fluoride in large
quantities may be followed by rapidly developing signs and
symptoms, which may result in death. When it is ingested in
relatively small amounts during the period development, it
may produce changes in the quality and appearance of enamel
(fluorosis). When somewhat larger amounts are ingested over
a period of years, changes in the quality and the quantity of the
skeleton may occur. This, in fact, is the basis of the use of
fluoride ion for the treatment of osteoporosis.
Important Information Before Any Calculation
Percentage “%” means parts Percentage “%” in fluid
per hundred (pph)
means gram per 100 ml
1 ounce = 28.4 grams
8 ounces = 227.2 grams
Atomic Weights:
Na = 23
F = 19
Sn = 119
P = 31
O = 16
“ppm” means parts per
million
ppm = 10,000 x pph “%”
Example: NaF
23+19 = 42
19/42 = .45 or 45%
Calculation of Fluoride Ion in Fluoride
Compounds
•
What is the information being requested?
Concentration or Quantity of fluoride ion. Follow
three simple steps in calculating the fluoride ion in
fluoride compounds.
1. Determine the fluoride compound.
You should know the fluoride compound (e.g. NaF), its
concentration, and the weight in “milligrams” of that
product (only if you are interested in weight). This
information can be calculated from the information provided
in the product’s label.
Calculation of Fluoride Ion in Fluoride
Compounds
2. Calculate the Ratio of Fluoride Ion
This ratio is the key factor for all of the calculations of
fluoride. It is the result of the atomic weight of fluoride
multiplied by the number of fluoride atoms in the compound
divided by the total molecular weight of that compound.
For example: NaF has a ratio of .45 of fluoride ion. This
0.45 is equal to 19/42. “19” is the atomic weight of one
fluoride atom. “42” is the molecular weight of the
compound.
Calculation of Fluoride Ion in Fluoride
Compounds
3. Multiply
Multiply the calculated ratio by the percentage, ppm, or the
weight of the fluoride compound to get the percentage, ppm,
or the weight of the fluoride ion in that compound.
Calculation of Fluoride Ion in Fluoride
Compounds
• Example:
How much F is in 10 ml of Fluorigard mouth rinse?
1. Fluorigard has 0.05% NaF (from the label). From the percentage given
0.05 gram of NaF per 100 ml
= 50 milligram of NaF per 100 ml
= 5 mg of NaF per 10 ml
2. The ratio for NaF is 0.45
3. Multiply
-If we are interested in concentration of fluoride ion, then we multiply
the percentage of the compound (0.05%) by the ratio. 0.05% x 0.45 =
0.0225% fluoride ion (concentration in % pph); To get the ppm, multiply
0.0225 % x 10,000 = 22,500 ppm of fluoride ion in Fluorigard mouth wash
-If we are interested in weight or the quantity (as the example
requested), then we multiple the weight of the compound in “mg” by the
ratio; 5 mg x 0.45 = 2.25 mg of fluoride in 10 ml of Fluorigard mouth wash