Flouride Effects and Dental Flurosis

At the beginning we`ll start talking about Flouride Effects ;

The main and first most important effect of fluoride is the

Inhibition of dental caries:

1 -Direct effect on the development of the enamel ; by which the fluoride replaces the OH group of the hydroxyapatite to form calcium fluroapatite which is more resistant to solution by acid than the hydroxyapatite

2 -Topical Effect : fluoride in the saliva interacts with carious process in three ways :

a. F has antibacterial propertiesb. It inhibits demineralization and enhances re-mineralization of Ca and P in the

enamel of incipient lesions during acid challenge " a better more resistant surface "

3 -Its suggested that the fluoride reduces the tendency of the enamel to adsorb salivary proteins and by this plaque wont build up quickly ,it also works on affecting the bacterial enzymes , two of these enzymes are : Endolase and ATPase.

**Note : Endolase Enzyme is related to bacterial metabolism and is important in glycolysis process " Important process by which sugar in analyzed to use energy to

the bacteria"

**Inhibiting The ATPase will inhibit the hydrogen pump and then the PH of the cell becomes more acidic and then the Bacterial cell will eventually die.

#Now we`ll Discuss The Flouride Therapy: Mainly two types:

1 -systemic type : water fluoridation / supplements

2 -Topical type: a. professionally applied : gels , prophy pastes , F-varnishes.

b. Self- applied : dentifrices , mouthrinses

--------------

Lets start with the systemic type: A- Water fluoridation :

1-most effective method in preventing caries in which the patient will be getting the max. benefit with the least cost .

2-It offers caries reduction "50% - 70%"

1 | P a g e

3 -doesn’t require any cooperation from the patient

4 -available to everyone , safe and economical.

**Discontinuation of F-water results in a return to previous levels of carious activity " F-protection is reversible "

-The range or concentration of fluoride varies between 0.7 – 102 " this depends on the climate ; hot climate means people are drinking more water so ; it`s 0.7 and vise versa "

-regarding Flouride protection ; it`s higher on the anterior teeth than the posterior " because of the fluoride ability to to resist caries on the smooth surfaces than on the

pits and fissures "

-F- Deficient area`s patients are at higher risk to caries " so they`re advised to take supplements which are chewed and swallowed "

-Amman`s water supply contains only (0.1- 0.5 ) ppm of fluoride while in irbid it`s near optimum " 0.6" ppm

the highest amount of fluoride was detected in "zai " water station in 2007 .

Jordan water company "meyahona" has started a fluoride study in cooperation with various governmental and non-govermental institutions.

B- Fluride supplements : Before prescribing them , we should take in consider the following :

1 -total fluoride intake " if the child is taking fluoride from other sources like F-water ,dentifrices, foods or drinks "

2 -Caries Risk status " we only prescribe them to children with high caries risk status "

prescription are also based on the american academy of pediatric dent. , where the 1- age , 2- level of fluoride are both involved .

Table in the slides " page 16 "

As you can see , we don’t prescribe anything for patients up to 6 months.

we usually prescribe for those who have water fluoridation less than 0.3 ppm or 0.3 – 0.6 " more than 0.6 ppm we don’t prescribe supplements"

*dosage as we previously said ; depends on the age and F-waterDisadvantages of the Supplements :

2 | P a g e

1 -expensive 2 -poorer attitude of the parents may lead to less knowledge and acceptance of F .

3 -development of enamel opacities and fluorosis " if excessive"

*we should instruct the patient to first chew then swallow and we should take care in prescribing them to patients before "3-6 years " because of fluorosis risk .

**50 – 80% caries reduction

------

Now we`ll discuss the second type of fluoride therapy whichis the Topical type:

1 -professionally applied: a. Flouride Gel : "mostly used "

1 -easier to apply 2-adherent to the tooth

3 -wont penetrate proximal areas " use floss to apply it between the tooth "

*no difference in the chemical components compared to the Flouride solution , " some preperations comes in the form of solution which is not as thick as the gel and it`s good in areas where we need fluoride to go between the teeth in the inter-proximal

areas "

***Indicated in moderate – high risk caries patients and non-flouridated communities "

Gels- Preparations :

1 -SnF 8% The bad thing about it is that it may cause staining of the teeth + it`s taste is not well accepted by children "metallic taste "

2 -NaF 2% " am not sure about this , in the slides it`s written 1% but during the lecture the doctor mentioned that it`s 2% "

" "� جدًا مهمة ًالنسب

so , Back to the NaF , it has a neutral PH so it`s good in enamel erosions , carious exposed dentines and where the enamel surface is porous " people with tooth

sensitivity "

3 -APF " acidulated phosphate fluoride : " used in the clinic , and comes in a concentration of 1.23 , %

it consists of " NaF , Hydrofluric acid and orthophosphoric acid.

3 | P a g e

-better taste -no tooth staining

low PH because of the acid in it " enhance fluoride uptake / because acid etched enamel absorbs fluoride better "

-presence of P help suppressing the enamel dissolution

-Longer lasting benefits following the termination of treatment.

**Regarding the application frequency : -semi annual " twice a year " and it can be changed depending on the caries risk of

the child

**Caries reduction : 30-50%

**Thixotropic gel " a type of gel that becomes a solution upon pressure / no need for cleaning prior to application"

b. Fluoridated prophylaxis paste : it`s not essential before the application of fluoride because it removes up to 4 micrometer of the enamel surface " which is most rich in fluoride so significant loss

of fluoride may occur , " but if you have heavy plaque or calculus then they have to be removed before applying the fluoride " if a patient cleans his mouth regularly then you don’t have to

use a prophy paste before fluoride application "

c. Fluoride Varnishes : vehicle for holding F in a close contact with the tooth for a long period of time because they are adhesive and efficacious in delivering and retaining F on the tooth structure.

**40-56 % Caries Reduction.

**Uses :1 -High carie risk children "specially to arrest incipient lesions "

2 -caries control in special need patients

3 -children with head and neck radiation and on chronic oral medications

4 -ortho- patients " prevent de-Ca beneath the ortho bands"

-easy and safe .

*Reapplication Is Necessary / Main cariostatic effect of the varnishes is the remeniralization of early carious lesions.

**application freq : .

-Semi annual " twice a year " but for high caries risk patients it should be "3-4 x/ year "

4 | P a g e

**Fluoride Varnishes Types :

1 – duraphat 5% NaF

2 -Fluoro – protector 1% di – F –Silane

3 Durafluor " it`s nice and similar to duraphat but it has xylitol In addition / to improve the taste and pt. acceptability "

4 -Cavity shield – most recent type – 5% NaF in resinous Base / avoids wastes , prevents over application because it comes in separate carpules for each patient so less chance of toxicity too .

*Application technique : 1-prohylaxis – plaque removal is`nt critical prior to application " unless oral hygiene

is terribile "

2 -Isolation – dry the teeth , place cotton rolls.

3 -varnish dispensed 0.5 – 1ml for the entire dentition / apply with disposable brush / dental floss for interproximal areas , avoid getting on ST , sets in few sec .s

4 -entire process takes 3- 4 minutes.

**It takes one minute for 95% of fluoride in varnish to get absorbed

**The only disadvantage of the varnish is that is causes yellowish – brown discoloration " temporary "

**you should instruct the parents that the staining is temporary and that it will vanish upon brushing / but children should avoid brushing for the rest of the day and also should avoid eating for 2 hours " in fluoride Gel , child mustn't eat for 30 minutes " ,

also soft diet for the rest of the day is advised as well.

*F- varnishes not intended to adhere permenantly to the tooth but to remain in close contact with the enamel for several hr.s and then we end up with a F- rich tooth surface.

2 -Self – Applied Fluoride " Topical Type: "

a. Dentifrice (TB) : Contents :

1 -Amine fluoride or SnF (0.4 % ) or 0.76 % sodium MFP ( 1% fluoride ion ) ( colgate / colgate –palmolive co )

2 -SMFP better than SnF / no staining / neutral PH

3 -Ca pyrophosphate abrasive (crest & gamble )

5 | P a g e

*make sure that the dentifrice used is ADA approved.

*most appropriate F concentrations recommended by ADA : 500- 550 ppm in children

1500- 2500 ppm in adults

***Correct TB amount is bean size for children and even less for infants.

b. Mouthrinses:

- Indications : rampant caries / ortho therapy / salivary depression caused by pathologic conditions or medications / jaw fixation/ dental hypersensitivity .

**NaF = agent of choice it reduces caries by 40 % compared to APF which reduces only 20 – 30%

**Recommended Dosage: 1 – Daily rinsing " low conc . 0.05% " / 1-2 mins twice a day

2 – weekly rinsing : " high conc. 0.2% / once weekly"

#Based on a study by erricsson , preschool children injested average of 0.4 mg of F per rinse because of inadequate swallowing reflexes , that`s why they decided that children below the age of 6 years shouldn’t use mouth rinse

من , أكبر هم لمن فقط بنوصفو إيا بنوصفلهم فما بمضمضوًا هم و يبلعوًا 6ممكنسنوًات .

other types of self – applied gels: -High concentration APF gels for semi-manual office application / not found in

pharmacies.

-there are also lower concentrations of 0.5% APF gels or 0.5% NaF or 0.4 % SnF or other fluoride gels wich are available in the pharmacies and can be used directly by the patient`s parent.

*we should worn the parent if their child is brone to fluorosis or staining.

*Dr. Asked About the type of fissure sealant in the last slide in the fluoride 1 lecture " page 28 "

-ans . Fujii-VII

6 | P a g e

Fluoride Toxicity : increase in the levels of fluoride

two types :

1 -acute toxicity : high amount / excessive amount of fluoride / symptoms of acute toxicity : systemic manifestations

2 -Chronic toxicity : high amount of fluoride for a long period of time / causes fluorosis

**now we`ll discuss the term fluorosis : Revirsible condition , and it`s caused by exposure of a developing tooth to an increased amount of fluoride resulting in mineralization defects of the enamel

*slide page 3 = dental fluorosis in a 8-9 yrs child grew up in fluoridated Auckland in newzealand

*Clinical appearance : -Bilateral opaque white areas in the enamel

-tooth is fully functional and resistant to acid attack " fluoride makes it very resistant to acid attack actually. "

-enamel more porous / can get stained.

*Types of fluorosis: 1 -very mild : small – paper white areas , involves less than 25 % of the enamel

2 -mild : opaque areas " 50 % of the enamel"

3 -moderate : whole enamel may be affected with paper white or brown areas.

4 -severe : enamel is grossly defective , opaque , pitted , stained , brown and brittle

**Please go back and check the slides for picture although they are not clear**

*Histopathologic appearance : -non pitted fluorotic enamel with subsurface porosity below well –mineralized

surface zone

-this surface porosity is what creates the white opaque appearance

-with increased severity of fluorosis , porosity extends toward DEJ , breakdown and pitting of enamel may result.

*The question is ; When does fluorosis occur? -Enamel formation stages are :

7 | P a g e

1 -presecretory stage

2 -secretory ( protein synthesis and secretion , early mineralization )

3 -maturation ( matrix removal and mineral deposition ) where most of the trouble occur

So, - presecretory stage =high amount of fluoride will affect the aminoblast and

their differentiation to polarized cells .

-secretory stage = fluoride may affect the secretion of extracelluler organic matrix

-Early maturation = the ameloblast secrets the protenase , the fluoride can inhibit the protein secretion " increased fluoride in matrix"

-Maturation = when the matrix has to be removed and the mineral deposit , the fluoride will also inhibit this process through something which is called the " zone refinement hypothesis " = Decrease in the number of ZR cycles ( cycles = removal of protein and addition of minerals ) change in the crystal size and morphology in subsurface of fluorosed enamel.

**go back to the slides

-Critical factors in Fluorosis formation : Dose & Dosage:

If the dose > 0.1 mg/ kg = fluorosis riskDuration is = late secretion / early maturation period " maturation is more

sensitive " -if patient exposed to both durations then it`s more severe .

-permenant incisors and canines affected by fluorosis at age of 1.5 – 2.5 yrs .

-permenant post. Teeth affected mostly at the age 3-6 years.

**Characteristics of fluorosis : -mottling is usually endemic in areas where F . 2 ppm in drinking water " so if

you find one member of the family affected , usually most of the family will be affected "

-only those who lived in a high F- area during dental development show mottling , older visitors to the area wont be defected

-Deciduous teeth are rarely effected /if affected mostly the E`s will get fluorosis

8 | P a g e

**Risk Factors :

1 -Very Long Exposure to fluoride "duration related" 2 -Increased risk with excessive use of fluoride supplements " dose related"

3 -lowest risk is during secretory stage " < 13 months of age "

4 -highest risk during both secretory and maturation " birth – 4 years"

5 -Risk increases with increasing the dose

**So , Factors : Dose , Duration , Age , Timing , other F sources.

**How to differentiate between the Fluorosis and the Enamel Hypoplasia ?

1 -Family history : if fluorosis most of the members of the family and people living in that area should be affected

2 – History of trauma : hypoplasia

3 -Hx of fluoride intake = fluorosis

4 – Localized Defect = Hypoplasia

5 -Generalized defect = Fluorosis

*Management : the problem is cosmetic ; many options of management:

-restorative options -microabrasion -composite resin

-porcelain veneers when they become adults -tooth mousse – good for moderate cases

**Fluoride toxicity :

1 -Certainly Lethal toxic dose = death

- acute Lethal dose = syptoms of toxicity / acute lethal dose of F in the form of NaF in an adult male 32- 64 kg weight results in death within 2-4 hrs if first aid is`nt applied immediately

-CLD for 70 kg adult = 5-10 gram , corresponds to F-dose for 32-64

-CLD for a child 10 kg " 12- 18 month of age " is 320 mg of fluoride

2 -Probably toxic dose=

9 | P a g e

symptoms of toxicity

5 mg F/ kg

تناسب و نسبة

The example in the slide fluoride II page 19 :

the child is 11.3 kg

PTD = 5 mg F / kg

means ; 1 kg of wt 5mg of fluoride

11.3 kg of wt X

X= 56.5 ( approximately 57 ) mg

This quantity of Fluoride is contained in :

1 -57 g of 1000 ppm F dentifrice 2 " -half the amount " 38 g of a higher conc. " 1500 ppm F dentifrice"

3 -approximately 500 ml mouthrinse " pepsi can or mug of a mouthrinse"

4 -57 x 1.0 mg F- tablets

5 -4.6 ml of 1.23% APF

**No clear relationship between fluorosis and cancer

now symptoms of acute toxicity:

1 -block of celluler metabolism / inhibition of glycolysis , nerve impulse and conduction disorders

2 -nausea

3 -vomiting

4 -hypersalivation

5 -diarrhea

6 -abdominal pain " irritation of the GIT through formation of HF acid "

7 -sweating , headache

8– myopathologic signs ; spasms ,hypotension , cardiovascular failure ,

10 | P a g e

disturbance of electrolyte balance and restoration is depressed insevere cases and may develop to respiratory acidosis and pt. may undergo unconsciousness / disoriented patient

**Management : 1 -estimate the amount injested

2 -minimize further absorbtion3 -remove Fluoride supplements

4 -support vital signs 5 -if vomiting hasn’t occurred give milk

6 -Hospitalization

in the past the used to use emetic syrup which is the ipecac / not used nowadays because the vomiting it induces doesn’t rid the body of the poisoning it also causes burning of the esophagus

another way of management is "management by dosage" if you estimate that the child has injested less that 5 mg / kg then give milk " Calcium content " the

observe up to 4 hours .

if the patient has injested more than 5 -15 mg / kg hospital admission

if more than 15 mg / kg hospitalization and more advanced management

**Death Reported due to F-toxicity : 3 cases :

1 -3 years old child died because he swallowed 24-38 mg F / kg" SnF " death after 3 hrs "

2 -27 months old / male / injested 100 F- tablets / 5 days later died

3 -3 yrs old inested 200 tablets / death occurred 7 hours latter

Next Lecture Calculations will be discussed.

Done by Ghadeer Afaneh

11 | P a g e

12 | P a g e