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  1. Mechanisms of Caries Reduction by Fluoride lecture -4-
  2. Studies revealed that fluoride taken systemically (before tooth eruption) and topically (following eruption of teeth) greatly reduces dental caries. The precise and complete mechanisms of actions F in relation to dental caries are not fully understood. There are three theories present explaining this role:
  3. 1st theory (Pre eruptive theory): This is a widely accepted theory claims that when F is taken during the period of tooth formation may cause changes in composition and morphology of teeth. Fluoride ions taken from surrounding tissue fluid may replace the hydroxyl group of the hydroxyapatite crystal forming a new crystal known as fluoroapatite crystal. Ca10(PO4)6(OH)2 + 2 F- Ca10(PO4)6 F2 + 2 OH-
  4. •2nd theory (post eruptive theory): •F ions present in saliva and dental plaque (from dental products; topical) will react with the outer enamel surface to enhance re-mineralization. Two types of reactions may develop: • The main reaction is formation of calcium fluoride, while the 2nd type of reaction is the formation of Fluoroapatite crystal.
  5. •Calcium fluoride is not permanent as it dissociated to calcium and F ions. •There for fluoridated products need to be applied continually and at a high concentration, •These types of reactions can be initiated at any time of subject life.
  6. •The presence of F in high concentration (more than 40 ppm) in dental plaque may affect the growth and fermentation of bacteria. •These by: Interference with bacterial adherence by retardation of extra cellular poly saccharide. Inhibition of intercellular enzymes as enolase and phosphatase. Thus inhibit the bacterial glycolysis and metabolism. In a high concentration, F is toxic to bacteria.
  7. The general mechanisms where by fluoride reduces dental caries involve the followings: •Increase enamel resistance or reduction in enamel solubility (Inhibition of de- mineralization) •Re mineralization of incipient lesion. •Interference with plaque microorganism. •Improved tooth morphology.
  8. Artificial water fluoridation Controlled adjustment of a fluoride compound to a public water supply in order to bring the fluoride concentration up to a level which effectively prevents caries.
  9. History of fluoride in dentistry • Dr. F. McKay begun extensive (1901,1908) studies……Brown stain……mottled enamel……now is called Dental fluorosis. •G.V. Black, USA in 1916 ……histological studies on teeth with brown teeth …..hypocalcification with no dental caries. •H.V. Churchill …..analyses the water ….high percentage of fluoride in water (13.7 ppm).
  10. History of fluoride in dentistry Dr. H.T. Dean …dentist carry out a series of epidemiological studies….. 1 ppm….. Inverse relationship between dental fluorosis and dental caries.
  11. •Dental fluorosis: •It is a developmental hypoplastic defect (; hypoplasia) caused by excessive fluoridation during the period of tooth formation. It is the 1st sign of chronic toxicity appears clinically as a white spots or lines involving incisal edge or cusps of posterior teeth or as a white opaque or brown area, in sever cases a corroded appearance will occur.
  12. •Using light and electron microscopy, in principle increased exposure to F during period of tooth formation •increased enamel porosity. •porous enamel because of increase of inter crystalline spaces; •these spaces are occupied by water and protein more than enamel. •In more sever condition changes involve enamel as well as dentin. •break down of the outer enamel surfaces.
  13. 10 9 8 7 6 5 4 3 2 FLUOROSIS 0.0 0.5 1.0 2.0 3.0 4.0 DMFT PPM F IN DRINKING WATER slight severe moderate mild F in excess of 0.1mg/ kg body weight = fluorosis
  14. The optimal level •The optimal level is (the level of F in drinking water causing maximum reduction of dental caries but with no clinical signs of dental fluorosis). • Epidemiological and observational studies however showed that a more sever dental fluorosis do develop some times in certain area of hot climate at one part per million, thus the optimal level of fluoride was changed to 0.6 – 1.2 ppm according to the temperature. In winter is 1.2 ppm and in summer is 0.6 ppm.
  15. Communal water fluoridation: •It is the controlled or artificial adjustment of the level of F in a communal water supply to achieve maximum reduction of dental caries and clinically no significant level of fluorosis. • Fluoride was 1st added to water supply in 1945 in Grand Rapids (Michigan) while Muskegon was the control. •Caries reduction was reported to be 55%. In USA, now more than 126000,000 people are receiving systemic fluoridation. It is also applied in Europe and other countries.
  16. Artificial water fluoridation Controlled adjustment of a fluoride compound to a public water supply in order to bring the fluoride concentration up to a level which effectively prevents caries.
  18. Alternative to water fluoridation:
  19. School Water fluoridation
  20. ##Supplements should be given daily, not with milk In prescription of F tablets several important factors should be taken in consideration. • - F content of the water supply, (communal or bottled water). Applied only in non F. area or those with low F. level. • - Age of the child. • - Co - operation of parents. Fluoridated tablets (drops ). NaF, 2.2mg (1 mg F). 1.1mg (0.5 mg)
  21. • •
  22. Drops: 10 drops = 1 mg F/ L = 1ppm (also available in 0.125 mg, 0.25 mg and 0.5 mg/ L). Another Program: - Started at 3 years of age give 0.5 mg/day till 13 – 15 years. - In presence of dental caries (0.25 mg/day till 3 years) then 0.5 mg/ day till 13-15 years. Instructions: 1- Given daily. 2- Tablets crushed between teeth. 3- Each bottle contains not more than 264 tablets, to avoid acute toxicity after the accidental ingestion of fluoride tablets. 4- Dentifrices used should be with out F, or with a low concentration.
  23. •Studies showed that tablet taken in the first 7 years of life provide reduction of 39% - 80%. •Caries reduction in children was found to be more in primary teeth when pregnant mother taken fluoride, •other studies showed no differences as placenta regulates amount of fluoride reaching fetus.
  24. Fluoridated Salt: •It is controlled addition of F to domestic salt for purpose of caries prevention. • It was introduced first in Switzerland, 1955. •It is considered next to water fluoridation regarding caries reduction. • F is added to salt inform of, KF or NaF in different doses, 250 mg KF/ kg (or 225 mg NaF/ Kg) salt, •based on adult salt consumption estimates of daily salt, about one mg is ingested daily.
  25. Advantages of salt fluoridation are; •low cost •ease of implementation •no personal efforts is needed. •Effective in caries reduction for permanent as well deciduous teeth. •Safe as there is minimum possibilities of dental fluorosis. Disadvantage: • children would start to use salt too late in life, or they used to take small amount of salt. •Salt fluoridation need community education and promotion, •in addition there is international efforts to reduce sodium intake for controlling hypertension. •
  26. Fluoridated milk: •Human and bovine milk contain a low level of F about, 0.03 ppm. • Milk is a good food for infant and children, it is a suitable vehicle for supplementary F to children, it is an excellent source for calcium and phosphorous in addition to vitamin D. •Milk is essential for development of bones and teeth. • The concentration of F in milk is 2.5 ppm to 6 ppm, as calcium in milk may react with F reducing the amount of free ionic fluoride actually absorbed.
  27. The bioavailability of F from milk is in similarity to water, other studies showed that milk may retard the absorption of F from GIT, but does not prevent F absorption. Fluoridated milk can be used in home and school programs, with caries reduction of 70%. •The disadvantages of milk fluoridation are the high cost, thus the consumption of milk vary between different socioeconomic level. •Another disadvantage of milk, is that producing f milk need a high level of expertise, explaining its high cost. • Some children dislike milk, for them a fluoridated juice can be used.
  28. Topical fluoride therapy: • This term refers to the use of systems containing relatively large concentration of fluoride applied locally or topically to erupted tooth surfaces in order to prevent or arrest dental caries. The primary reactions product involved the transformation of surfaces hydroxyapatite to calcium fluoride.
  29. •Calcium fluoride is a loosely bound fluoride, dissolved rapidly and therefor to increase fixation of fluoride it needs to be applied frequently and continuously. •The use of topical fluoridation started in 1940, to control dental caries. • The best time of application of topical agents is in the post eruptive maturation period that is the two years after eruption. •Ionic exchanges continue between the oral environment and outer enamel surface.
  30. •1- Self – applied fluoride; a relatively low concentration of fluoride applied by individuals themselves. The concentration of fluoride is about 1000 ppm. This system includes: •- Dentifrices •- Mouth rinses •- Fluoridated gel •Agents can be used once or twice a day used once or twice a day, and a combination of two types can be applied.
  31. Professionally applied fluoride It is the periodic application of a high concentration of fluoride to the erupted teeth by dentists or dental hygienist The concentrations of fluoride are 9000 – 19000 ppm, it may reach for some agents to 23000 ppm or more. This system involves: •Solutions •Gel •Varnishes •Prophylactic paste(pumice) •Others (; foam, slow- release device) Agents can be applied periodically according to the need of the patient (every three or six months) or once a year.
  32. Efficacy of topical fluoride: The concentration of fluoride used. With increase of fluoride ions concentration in the topical agents give more chance for reaction of ions with outer enamel surface to enhance re-mineralization. The frequency and duration of application. Application of fluoride agent more than once daily (for self - applied fluoride) or every three or six months (for professionally applied fluoride), will increase the efficacy and benefits of agents. The specific fluoride agent or compounds. The solubility of fluoride compounds differs thus affecting the concentration of ionic fluoride release, thus the benefits of the agent. Further, presence of other metal ions as tin as for (SnF2) may enhance re mineralization compared to other type of agents.
  33. Self-applied topical fluoride A-Fluoridated dentifrices The first clinical trail of fluoridated dentifrices initiated by Bibby 1942, the active agent was sodium fluoride, and the abrasive was dicalcium phosphate (DCP). The general functions of these dentifrices are: Physico – mechanical function; that is by the action of the abrasive materials and the toothbrush. Chemical function; that is by the reaction of fluoride with the outer enamel surface and the antimicrobial effect.
  34. Types of fluoridated agents in dentifrices include; •Sodium fluoride (NaF). •Stannous fluoride (SnF2) • Sodium monofluorophosphate (MPF) •Amine fluoride •Combination of NaF and MPF
  35. •The range of fluoride concentrations in these agents is 500 – 1500 ppm. •The content of fluoride in dentifrices will decrease with the increase in the time of storage i.e six months or more. • The type of fluoride agent used must be compatible with the constituents of the tooth paste especially the abrasive systems. Types of abrasive; •Ca- pyrophosphate •Na- metaphosphate •Silica •Others
  36. •Following brushing there will be retention of fluoride in the oral fluid and dental plaque. Fluoride ions released gradually in the saliva and there by maintains a degree of protections against caries. •The increase in the frequency of brushing will increase the benefits of fluoride. Studies recorded caries reduction by using fluoridated dentifrices about 25 – 30%.
  37. •A brush full of 1000-ppm paste may contain (1 mg F ions). • Child may swallow pastes accidentally, at this age the child cannot control muscles of swallowing. •Thus brushing twice a day with 1000 ppm fluoridated paste the child may swallow 0.5 mg F/day. •The child may be at risk to be affected by dental fluorosis, especially in fluoridated area or taking fluoride supplements. •
  38. Clinical recommendations for using fluoride toothpaste in childern
  39. •Twice daily use of fluoride toothpaste, in combination with oral hygiene instructions, is the cornerstone of any preventive programme for children, irrespective of caries risk. •Although the caries-preventive effect is recorded only for concentrations of 1000 ppm and above, toothpastes with lower concentrations (500-550 mg/g) may have some beneficial effects and could be considered for children at low caries risk where the risk of fluorosis is of concern. •Brushing under supervision is essential. •Note: mg/ g is equal to ppm.
  40. Good practice points on brushing behaviour: •Tooth brushing should be conducted so each tooth surface is reached and brushing should exceed 1 min, also in preschool children. •• Children should avoid rinsing with a lot of water afterwards. •• Children’s teeth should be brushed using either a soft manual or power toothbrush.
  41. B-Fluoridated mouth rinses It was started in the early 60,s of the last century. Used for individuals, and in school programs. It is indicated in following conditions: Primary preventive programs for children and adults In subjects with high risk to dental caries. Patients with rampant caries. Patients with hypo-salivations or xerostomia. Patients with sensitive teeth due to tooth wear as (abrasion, attrition, erosion) or because of exposed root. Patients with periodontitis and root caries. Patients with orthodontic appliance.
  42. Types of agents used: Sodium fluoride, it is the main type used in health programs, it is of two types neutral or acidified (APF) forms in a water vehicle. Concentrations 0.2% (900 ppm F) applied once a week. 0.05% (225 ppm) applied daily.  Stannous fluoride, Concentration 100, 200, 300 ppm. Others, Amine fluoride or ammonium fluoride. A 10 ml of rinse used by forcefully swishing of liquid around the mouth for one minute then expectorate.
  43. Fluoridated mouth rinse should not be given: •To children under six years of age, as they cannot control muscles of swallowing. •Children living in fluoridated area or receiving fluoride supplements. Studies reported a caries reduction about 30% by the use of F rinse. Note: Fluoridated mouth rinses should not substitute fluoridated dentifrices, rinses is usually supplement toothpaste.
  44. C-Fluoridated Gel •It is used in home programs. Types of agents: •Sodium fluoride or acidulated phosphate fluoride (concentration 5000 ppm). •Stannous fluoride (0.4%). These can be applied using special tray or applied directly to teeth by toothbrush. Applied for 1- 5 minutes, then expectorate. Patients advised not to rinse by water or eat or drink for at least 30 minutes.
  45. C-Fluoridated Gel Indications for use: Patients with rampant caries. Patients with xerostomia. Patients with sensitive teeth due to tooth wear as (abrasion, attrition, erosion) or because of exposed root. Root caries.
  46. C-Fluoridated Gel •It can be used for four weeks course, when the onset of the disease is stopped the patient can switch back to mouth rinse. •Fluoridated gel is not recommended for children under 6-years of age. • It is used in combination with dentifrice, and not preferable to be used with mouth rinse. •
  47. Professionally applied fluoride: #Medicaments typically dispensed by dental professional in the dental office to prevent or arrest dental caries. #Materials applied are in forms of solutions, gel, foam, varnishes, pumices, others (fluoridated restorative materials, fluoride release devices). •
  48. Professionally applied fluoride: Different agents are available as: - Sodium fluoride - Stannous fluoride - Potassium fluoride - Zirconium fluoride - Titanium fluoride - Others. The concentration range of fluoride in these agents is 9000 – 22000 ppm. •
  49. Professionally applied fluoride: General method of application: Techniques followed for application of fluoride in the dental office are: - Tray technique: a small amount of fluoride is added to a tray then inserted in the patient mouth. Trays come in different shapes and types as foam lined or paper, custom vinyl etc. - Paint on technique, by which fluoride material applied to teeth by cotton applicator of brush.
  50. For both techniques: - Teeth are cleaned first (scaling and polishing) to remove dental plaque, calculus, stain and debris. These may interfere with the uptake of fluoride ions and reduce its effectiveness. - Teeth are isolated using cotton roll and saliva ejector. The patient seated in upright position with the head tilted downward to avoid accidental swallowing of the materials . - The fluoridated agent applied following dryness of teeth for 4 minutes (or according to manufacturer’s instruction). The amount of agent used must not exceed 4 ml to prevent acute toxicity. - Use un waxed dental floss to push the material between teeth. - Following treatment ask the patient to expectorate several times in disposable cup . - Instruct the patient not eat or drink for at least 30 minutes.
  51. Apply no more than 2-2.5 grams of gel per tray (40% of the tray’s volume) no more than 1/3 of the tray height
  52. Indications of use: In general materials indicated to be used at any age in: • -Prevention of dental caries • -control of rampant caries. •- Sensitive teeth and root caries.
  53. These materials are available in form of powder, solution or gel. The concentration of fluoride is 2 %. When powder is used 0.2 gram dissolved in 10 ml distilled water. When the agent is added to outer enamel surface calcium fluoride is formed. The following reaction take place involves; Sodium fluoride (NaF):
  54. The CaF2 reacts with hydroxyapatite to form fluoridated hydroxyapatites thus increase the stability of crystals and resistance to acid attack, furthermore it will enhance the re-mineralization of initial caries.
  55. •These agents have a basic pH, chemically stable when stored in plastic or polythene containers. •It should not be stored in a glass bottle as a fluoride ions will react the silica of the glass forming silicon di oxide reducing the free ionic fluoride necessary for caries reduction. • A flavoring and sweetening agents however can be added. •These materials are not irritant to the gingival, and do not cause discoloration to teeth.
  56. Method of application: •According to (Knutson,s technique), NaF fluoride agents are added in a series of 4 – weeks at ages of 3, 7, 11 and 13 years. Coinciding the eruption time of permanent teeth and also for protection of primary teeth. •The one disadvantage of this agent is that the patient need to visit dentist four times to accomplish this technique.
  57. •The success of any topical fluoridated agent depends on its capability of depositing fluoride ions in the enamel as fluoroapatite and not only calcium fluoride. • Fluoroapatite crystals are stable not like calcium fluoride. Acidulated phosphate fluoride (APF):
  58. •There are two ways of speeding to the reactions that lead to formation of fluoroapatite. •1- Increase concentration of fluoride ions in the agent. •2- Lowering the pH, that is making the solution more acidic. •Increase the concentration of fluoride ions lead to formation of calcium fluoride and phosphate, •while the presence of acid leads to break down of the outer enamel surfaces (hydrolysis of hydroxyapatite and release of calcium and phosphate) thus formation of DCPD (dicalcium phosphate dehydrate) Acidulated phosphate fluoride (APF):
  59. Acidulated phosphate fluoride (APF):
  60. •In both reactions phosphate formed. The increase in phosphate concentration causes the shift in the equilibrium of the reaction to right side that is in the direction of formation of fluoroapatite as well as hydroxyapatite crystals. •In another word, the increase in the concentration of fluoride ions and lowering the pH in presence of phosphate lead to increase deposition of ions in form of fluoroapatite crystals (ie increase fixation of fluoride ions in the enamel surface).
  61. •Acidulated phosphate (APF) is composed of NaF to which acid is added. The concentration of fluoride is 1.23%, the acid is in form of orthophosphoric acid the pH is 3.0. •(Note: APF solution can be prepared by dissolving 20 gm of NaF in one liter of 0.1 M phosphoric acid this known as Brudevold,s solution ).
  62. •APF comes in form of solution, gel and foam, to these coloring and flavoring agents added. • It is chemically stable when stored in plastic containers, and does not cause discoloration to teeth. •However it can - not be stored in glass containers as reducing the free F ions. •Other dis advantage of APF, that the repeated exposure of teeth with porcelain and composite restoration to it may cause loss of material and surface roughening with cosmetic change because of its high acidity. •The gel is more preferable than solutions as it increase the time of retention of the materials on the tooth surface.
  63. •The gelling material is in the form of carboxy methyl cellulose or hydroxyethylcellulose. •Another type of gelling material added known as thixotropic gel, it is a gel like material (not a true gel) as under pressure it behaves like solution and flow between teeth, at the same time it became viscous by low pressure thus will not flow behind the tray to enter the patient throat.
  64. Stannous fluoride (SnF2) •It contains cation (stannous) and anion (fluoride), both react with enamel surface forming calcium fluoride, stannous fluoroapatite and hydrated tin oxide.
  65. •These complex agents increase resistance of enamel to acid dissolutions. •Caries reduction by SnF2 was reported to be greater than NaF. •Stannous fluoride used in form of solutions. It is available in powder that is prepared by dissolving appropriate weight in distilled water.
  66. •For children the recommended concentration of stannous fluoride is 8% (dissolve 0.8 mg in 10 ml of distilled water) applied once a year (Muhler’s technique). • For adolescents and adults the recommended concentration is 10 % (dissolve 1 mg of powder in 10 ml distilled water).
  67. Advantages of SnF2 1- Effective in preventing caries, by rapid penetration of fluoride in deeper layer of enamel thus increase of the resistance of enamel against acid. 2- Highly insoluble tin- fluoro- phosphate complex act as a protective layer against acid attack. 3- Re mineralization of initial carious lesion. 4- De sensitization of teeth. 5- Antibacterial, includes both specific antibacterial effect against cariogenic bacteria, and non- specific effect against other type of bacteria. 6- Has an additive effect by tin ions in addition to fluoride ions.
  68. •1- Not stable in aqueous solution, it under goes rapid hydrolysis and oxidation to form stannous hydroxide and stannic ions. These may reduce the effectiveness of fluoride. Thus, stannous fluoride solution need to be freshly prepared. •2- Un pleasant taste with metallic astringent taste and highly acidic (pH 2.1- 2.3). •3- Reversible irritation to gingival, as gingival bleaching may occur. It is not recommended to be used in sever gingival inflammation. •4- Discoloration of hypo calcified area and staining of margin of restoration. Disadvantage
  69. Indication of use: 1- Primary preventive programs (once or twice a year). 2- High risk group and rampant caries (every 3 or 6 months). 3- Initial caries (3 or 6 months) 4- Desensitizing agents (once a week then every 3 – 6 months) 5- Patients with xerostomia ( 3- 6 months). 6- Patients with hypoplasia or calcifications (as amelogensis imperfecta or dentionogensis imperfecta). 7- Root caries.
  70. Fluoridated varnishes •These are slow release or semi-slow release agents. • Prolonged exposure time and high fluoride concentrations result in the formation of a large calcium fluoride reservoir. •Fluoride release continues for a long time, as for at least 8 hours or even for several weeks according to the type used. •Studies showed that the use of fluoridated varnishes resulted in the most significant caries reduction among topical fluoride agents (30-70% caries reduction).
  71. Types: 1- Duraphate: • It contains 5% NaF (2.26% F). It is viscous, resinous varnish. In contact with saliva, Duraphate hardens into a yellowish brown coating. 2- Fluor protector: • It is a polyurthan-based varnish contains 0.9% silane fluoride (0.1% F). The varnish is acidic and hardness in air in to a colorless, transparent film within 2-3 minutes. The silane fluoride, is insoluble in water but reacts on contact with saliva, releasing small amounts of hydrogen fluoride that penetrates enamel more rapidly than other types of fluoride. 3- Bifluoride 12: • Is a clear varnish containing 6% NaF and 6% CaF2, The varnish base consists of collodion and organic solvents.
  72. Indication of use: •- high risk group (to be applied 2-4 times / year). •- Initial caries even for children under 6 years of age as can be applied on the affected surface only. •- Highly indicated for sensitive teeth. •- Root caries. •Varnishes should not be applied in presence of sever gingival bleeding to prevent the development contact energy with the components of the varnishes.
  73. Fluoride containing prophylactic paste •Before applications of fluoride agents, it recommends to clean teeth and restoration by polishing with a rubber cup using pumice, in order to remove all exogenous deposit.
  74. Different types are available as: __Zirconium silicate contains stannous fluoride; __Silicon dioxide contains acidulated phosphate fluoride. __This paste is not a substitute for the topical agents; they are used in order to increase the accessibility for fluoride ions by tooth surface. __Thorough prophylaxis will remove a thin layer of enamel (1 – 4 µm), thus it is always recommend using F pumice.
  75. Fluoride and restorative material: •Different restorative material may contain fluoride to be released slowly to prevent recurrent caries as glass ionomer cement, resin modified glass ionomer cement, resin composite, amalgam. Fluoride may be added also to fissure sealants. Fluoride release devices: •Devices allow for a slow release of F ions, as glass beads, copolymer membrane type and others. Indicated for patients with high risk group and those wearing orthodontic appliance. • Not to be given for a child receiving fluoride supplements. •
  76. Fluoride toxicity •There are two types of toxicity related to fluoride: •1- Acute fluoride toxicity due to single ingestion of a large dose of fluoride at one time. •2- Chronic fluoride toxicity due to long term ingestion of small amount of fluoride for a long time.
  77. Acute fluoride toxicity: •It is the rapid excessive ingestion of fluoride at one time, the speed and severity of ingestion depend on amount of fluoride ingested and the weight and age of the victim. The certainly lethal dose (CLD) for adults, 70 Kg weight is 5 – 10 gm F/ Kg body weight. •For children the CLD is not well known but the probable toxic dose is • 5 mg / kg body weight. •It is always recommended not to dispense more than 264 mg of F at any time. •Note: the PTD is the threshold dose that trigger immediate emergency.
  78. General factors affecting acute toxicity: 1- Form of administration: Fluoride toxicity from solution agents is greater than others form because of faster absorption of fluoride ions. 2- Rate of absorption: acidity and empty stomach in addition to highly soluble agents may increase the rate of absorption of F ions thus toxicity. 3- Age: toxicity is more among younger children, also the body weight is an affecting factor, as increase body weight may have less toxicity.
  79. Signs and symptoms of acute toxicity: •GIT; nausea, vomiting, diarrhea, abdominal pain, and cramps. •CNS, paresthesia, tetany, CNS depression and coma. •CVS; weak pulse, hypotension, pallor, shock, cardiac irregularities and ultimately failure •Blood chemistry; acidosis, hypocalcaemia, hypomagnesaemia.
  80. Emergency treatment depends on the dose ingested: 1- Less than 5 mg/kg body wt., - give calcium orally or milk to relive gastro intestinal symptoms. - Induce vomiting if necessary - Keep child under observations. 2- More than 5 mg F/ kg body wt.; - Empty stomach by induction of vomiting using emetic materials. - If vomiting is not possible as for infant or young child or retarded patient then endotracheal intubation is performed before gastric lavage. - Give solution as milk or Ca- gluconate 5% or Ca – lactate solution. - Admit to hospital.
  81. 3- More than 15 mg / kg. - Admit to hospital immediately. - Cardiac monitoring - IV administration of 10 ml of 10% Ca gluconate solutions. - Monitoring of electrolyte especially Ca and K. - Adequate urine out- put by diuretic. - Supportive measures for shock.
  82. Recommendations to avoid toxicity: 1-Use small amount of topical fluoride agents in the clinic (not more than 4 ml). 2- Self applied fluoride for children need to be observed by parents. 3- Keep F supplements out of the reach of children.
  83. Chronic Fluoride toxicity: It is long term ingestion of small amount of F for years, in teeth is dental fluorosis and in bone is skeletal fluorosis. Chronic toxicity affecting teeth may lead to dental fluorosis, while affecting bone may lead to skeletal fluorosis. Dental fluorosis: Dental fluorosis, a hypoplasia tooth enamel or dentin, ranges in intensity from barely noticeable whitish striations to confluent pitting and staining. Various indexes or classification systems have been used in surveys to measure the presence and severity of enamel fluorosis.
  84. Dean's classification system has been used most frequently over the years for assessing fluorosis.
  85. Skeletal fluorosis: A term used to describe any changes in bone because of ingestion of at least 8 ppm of fluoride for years. Signs: - More dense bone. - Diffuse bone. -Thickening of cortical bone. -Numerous exostoses. Through- out the skeleton. -Calcification of ligaments and tendon -Crippling fluorosis in severe cases.
  86. The severity of these signs depends on: 1- The duration of fluoride intake. 2- Total amount of fluoride ingested. 3- Concentration of F ingested. 4- Age of the individual. This condition is seen in polluted area due to industrial factories or volcanic actions.