6DM FLUORIDE PREVENTION

Transcription

1 6DM FLUORIDE PREVENTION

2 Fluoride is the most effective in caries prevention when a low level of fluoride is constantly maintained in the oral cavity. An important reservoir of this fluoride is in plaque, in saliva, on the surfaces of the oral soft tissues, and in loosely bound form on the enamel surfaces.

3 Fluorides in the enviroment is the most electronegative of all chemical elements and is therefore never encountered in nature in element form may occure in a wide variety of minerals (cryolite, apatite, fluorspar, mica) fluoride concentration (F c) in soil increases with depth all waters contain fluoride in varying concentration (sea water itself contains F in level of mg/l) F is also widely distributed in the atmosphere (originating from the dust, gaseous industrial waste, domestic burning of coal fires, gases emitted in areas of volcanic activity) tea plant has a F conc. ranging mg/kg fish has a F conc. range of mg/kg

4 Fluoride metabolism and excretion Fluoride absorbtion 75-90% of the F ingested each day is absorbed from the alimentary tract (higher proportion from liquid than from solids) the half time absorbtion is 30 min peak plasma conc. occur within min. (normal level in plasma 0,14 0,19 ppm) absorbtion across the oral mucosa is limited and probably accounts for less than 1% of the daily intake plasma F levels are roughly equal to the F conc. in drinking water - 99% of the body burden of F is associated with calcified tissues

5 Fluoride excretion 10-25% of the daily intake of F is not absorbed and is excreted in the faeces the elimination of absorbed F occurs almost exclusively via the kidney ( the renal clearances of Cl, I, Br are less than 1.0 ml/min, the renal clearances of F is 35 ml/min) less than 1% of the absorbed F was recovered from the saliva( c of F in whole saliva is in the range of 0.01 to 0.05 ppm) the c of F in human milk is 0.01 to 0.05 ( no evidence of transfer F from plasma to breast milk, but F crosses placenta)

6 Fluoride in teeth F content of tooth tissues reflects the biologically available F at the time of tooth formation (in the bulk of the enamel, once formed, it remains constant, in contrast to the F levels in bone, which continue to accumulate throughout life) post-eruptive change is reflected in the outer layer of enamel owing to diffusion of F from the oral environment F distribution in teeth are in high c ( mg/kg) in surface enamel, and a lower c (50-100mg/kg) in deeper enamel layers

7 Demineralization breach of dynamic balance of enamel and the oral cavity with decreasing ph of environment, the state of undersaturation of Ph and Ca ions, the ions diffuse from the enamel into plaque and saliva surface layer of enamel is well mineralized, the loss of minerals occurs in the subsurface Decrease of ph below 5.5 means start of dissolving the hydroxiapatite component of enamel

8 Remineralization in shifting the ph to alkaline side, saliva transports ions back into the enamel remineralization process is dependent on ph, and saturation of saliva ions Ca, PO4, F

9 Demineralization/Remineralization Carious process the earliest clinical evidence of the caries process is the white spot lesion, characterized by chalky white appearence radiographically, the surface layer is intact, but the zone of demineralized enamel can be noted beneath the intact surface layer

10 Demineralization/Remineralization Carious process Ca, Ph are lost from the tooth during demineralization and may be either precipitated together somewhere else in the tooth or lost to the mouth via the plaque and saliva Calcium and Phosphate in Remineralization Ca, Ph (PO 3 4) diffuse into the tooth from saliva and/or plaque fluid and precipitate as new material inside the early carious lesion Remineralization is an enrichment of the partially demineralized tissue via formation of redeposited mineral Ca, Ph available in sufficient quantities from endogenous sources

11 Remineralization Ca - necessary component of remineralization F enhances the crystal growth - catalyst for remineralization process - inhibits demineralization of crystal surface New mineral is formed (fluorapatit-like,hydroxyapatite-like) less soluble than original fewer impurities

12 Mechanism of action of F predominant effect is topical rather than systemic F can prevent mineral loss at crystal surfaces and enhance remineralization by calcium and phosphate groups because the mode of action of F is predominantly posteruptive, the prevention of caries requires lifelong exposure. When remineralization take place in the presence of F, the rebuilt enamel is more caries resistant than the original mineral and this effect is evident in even very low F c (less than 0.1ppm) across the liquid phase surrounding the enamel matrix

13 Mechanism of action of F F has an effect on the glycolytic pathway of oral microorganisms reducing acid production and interfering with the enzymatic regulation of carbohydrate metabolism the continuous presence of low levels of F in the plaqueenamel interface provides the most effective mode of remineralization How does F help to prevent tooth caries A) F promotes tooth remineralization B) F makes a tooth more caries resistant (HFA ph 4,5) C) F inhibits oral bacteria s ability to metabolize sugars

14 Safety and toxicity of F Acute toxicity (daily intake of F 0,05 0,07mg/kg/day) CLD (Certainly Lethal Dose) of sodium fluoride varies directly with body weight CLD for adult is mg F/kg CLD for chidren is 16 mg F/kg Acute poisoning cellular metabolism blocked inhibition of enolase in the glycolytic pathway interference with calcium metabolism nerve-impulse and conduction disorders

15 Acute poisoning General signs and symptoms the clinical course in acute F toxicity develops with alarming rapidity gastrointestinal pain diarrhea salivation nausea and vomiting neurologic effects: painful spasm, paresis, weakness, convulsion, stupor respiratory paralysis and cardiac failure

16 Treatment of acute toxicity an estimation of the amount of F ingested minimizing further absorbtion removing F from body fluids supporting vital signs Management by dosage < 5mg/kg give calcium(milk) orally and observe for a few hours 5-15 mg/kg - empty stomach with emetic give calcium orally admit to hospital

17 Treatment of acute toxicity Management by dosage >15mg/kg admit to hospital immediately induce vomiting cardiac monitoring and life support intravenous calcium gluconate

18 Chronic toxicity Dental fluorosis Dental fluorosis is a qualitative defect of enamel, resulting from an increase in concentration within the F microenviroment of the ameloblasts during enamel formation Manifestation very mild white spots mild-fine white lines moderate very chalky, opaque enamel severe mottling and loss of proportion of the outer enamel

19 Forms of fluoridation Endogenous: Fluoridation of drinking water Salt fluoridation Milk fluoridation Fluoride tablets Exogenous: Toothpastes Fluoride gels Fluoride varnish Fluoride solutions

20 Endogenic fluoridation Fluoridation of drinking water F in drinking water the most appropriate c of F in drinking water is 1.0mg/l ( most appropriate" means the c which at maximum caries reduction could be achieved while limiting dental fluorosis to acceptable levels of prevalence and severity) this standard is not appropriate for all parts of the world (0.5mg/l is appropriate limit for hot climate countries)

21 Endogenic fluoridation Fluoridation of drinking water Advantages: does not require cooperation of the recipient does not require direct involvement of health professionals index of return (how many times will the unit of currency invested into the fluoridation of water return) in New Zealand 38 caries reduction 30% - 40% Technology of fluoridation: Wet process: dosing F solution at the constant concentration Dry method: F dose in powder form (fluorosilicates sodium fluorosilicates ammonium fluorosilicic acid) Optimal level of F: 1 mg/1l water Mineral water: Different content F (Mattoni 3.2 to 3.53 mg f, Baldovská 1.01 mg F)

22 Endogenic fluoridation Salt fluoridation F salt should be considered where water fluoridation is not feasible for technical, financial or sociocultural reasons F salt contains 250 ppm F (NaF, KF) in the production it comes in the form of solution Recommended for use with the F content in drinking water less than 0.6 mg / l reduces the incidence of dental caries as F drinking water Disadvantages salt-free diet for young children salt restriction in pregnant women

23 Endogenic fluoridation Milk fluoridation Fluoridated milk milk is suitable vehicle for supplementing children s fluoride intake alternative method of total fluoride Fluoride is added before pasteurization addition of 100 ml 2.2% NaF solution for 1000 l of milk First time introduced in Switzerland 30% reduction in caries in 5 to 6 year olds

24 Endogenic fluoridation Fluoride tablets fluoride supplements have limited application as a public health measure overzealous use of supplements has been associated with dental fluorosis schedule has been proposed for supplementation of patiens at high risk of caries development who live in areas where the water supply contains less than 0.5mg/l of F. This schedule does not have an upper age limit, which is consistent with the view, that individuals may continue to be of high caries susceptibility beyond 8 years of age

25 Endogenic fluoridation Fluoride tablets NaF tablets One pack contains 250 tablets (62.5 mg F) administering at least 300 days a year Recommendation: slowly dissolve in the mouth 0.55 mg NaF, 0.25 mg F caries reduction 25% - 80% Disadvantages: adult supervision needed neurotoxic to the developing brain tissue

26 Fluoride tablets ½ Tooth paste w F no no yes no yes no yes F drinking water less than 0,3 mg/l ,3 0,6 mg/l more than 0,6 mg/l

27 Exogenic fluoridation Topical use of fluoride Individual application Group application Professional application

28 Exogenic fluoridation Topical use of fluoride Fluoridated toothpastes the use of F toothpastes has led to a 25% reduction in the prevalence of caries F contain approximately ppm of F (for children ppm of F) therapeutic toothpastes ppm of F all toothpastes have a similar effectiveness F in a form of aminfluoride or NaF Use 2x a day

29 Exogenic fluoridation Topical use of fluoride Fluoride gels and solutions professionaly applied topical F is indicated only in patients with moderate to severe caries activity gels are best applied in foam-lined mouth-trays and left in contact with the teeth for 4 min patients should abstain from eating, rinsing, drinking for 30 min after proffesional application Elmex fluid, elmex gellee

30 Exogenic fluoridation Topical use of fluoride Rinsing methods For domestic applications % NaF (1-2 min) For group application 0.2% - 0.5% NaF Bergrenn s method: children brush teeth with toothpaste for 4 min clean teeth with a brush soaked in 1% NaF application 4x a year

31 Exogenic fluoridation Topical use of fluoride Indications of local fluoridation: during preventive examination patients with high caries activity (6-12 times a year) patiens undergoing orthodontic treatment rampant caries from the xerostomia which follows radiation therapy, or prolonged medication of the neck and head

32 Exogenic fluoridation Topical use of fluoride Self-application use weekly at home not recomended for children under 6 years of age Fluoride mouth-rinsing In individual programmes based upon the individual s caries activity reduces caries by 20-50% 0.05% NaF used daily 0.2% NaF used weekly or fortnightly especially beneficial for patients undergoing orthoterapy and undergoing radiotherapy

33 Exogenic fluoridation Topical use of fluoride Fluoride varnishes caries reduction ranging from 50-70% applied with small brushes or syringes should be applied at intervals of 3-6 months no contraindications

34 Local fluoridation home care, professional INDICATIONS: Reduction in dental caries by increasing the resistance of enamel (21% - Cahen et al % - madlena, 2002) Remineralization early stages of tooth decay Desensitizing exposed necks Protecting the aburment teeth (dentures, orthodontic appliances) Remineralization of enamel after treatment (removal of the stone, making fotokompozitnej fillings)

35 Fluorides ANORGANIC : natrium fluoride NaF (Mirafluor) Stannous fluoride SnF2, natrium monofluorphosphate natrium fluor silicate ORGANIC : aminfluorid (Elmex GABA) fluorsilany (Fluorprotector Vivadent)

36 Aminfluorides Organic fluorides (Olaflur and Dectaflur) 1x synthesized 1957 On the tooth surface precipitate CaF2 - Stock fluoride inhibition of glycolysis Effects of quantity and nature of plaque The advantage of organic fluoride - increased absorption and retention F - a combination of hydrophobic and hydrophilic parts

37 Means of local fluoridation Child toothpastes: 500 ppm (Elmex aminfluorid) ppm (Lacalut aminfluorid) Mixed dentition toothpastes (6-12r.) : 1400 ppm (Elmex aminfluorid) 1450 ppm (Lacalut aminfl.+naf)

38 Means of local fluoridation Adult toothpastes: 1250 ppm (Elmex), 1400 ppm (Lacalut aminfluorid+naf) Therapeutic toothpastes: ppm (Colgate Duraphat) Adults toothpastes more abrasive (silica), other flavorings ("sting"), a higher content of F - not for milky teeth, in the permanent dentition and mixed according to the content of F

39 Means of local fluoridation Elmex Gel ppm F-, 2500 ppm (0.25%) aminfluorid, ppm NaF (1%) Home fluoridation 1x week Fixed day of the week Evening after brushing A small amount of gel - 2 cm, 1-2min No rinsing (just spit out)in adults, In adults - reduction in sensitivity necks, or xerostomia

40 Means of local fluoridation Elmex fluid professional fluoridation ppm F-, amine fluoride 2x per year Groups at high risk for tooth decay to 4x per year Fluoridation is part of the preventive inspection Intensive caries prophylaxis Mirafluor gel 1,23% NaF, 2x per year