Dental
Content
Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
DENTAL PRODUCTS
Introduction Dental hygiene has been considered as important since long. In order to maintain dental hygiene, numerous dental products are available in the market. Numerous chemicals find use in their preparation as well as in dentistry. Although it is well known that clean teeth keeps good health and clean teeth cannot decay, it is not possible to clean the teeth continuously all the years. Numerous factors contribute to dental decay and the problem of oral hygiene arises. A large number of inorganic chemicals and their preparations are known which find application in the practice of dental and oral disorders. As they come in contact with the human body, they are regarded like other drugs and pharmaceuticals. Dental products include (i) Anticaries (ii) Cleaning and (iii) Polishing agents. Anticaries Agents Dental caries or tooth decay is more or less a disease of the teeth caused by acids produced by the action of microorganisms on carbohydrates. This disease is characterized by decalcification of tooth accompanied by foul mouth odour. The exact cause and mechanism of dental caries is not known with certainty. However, it is accepted that dental caries first of all starts on the surface of the teeth. Acids produced by bacterial metabolism of fermenting carbohydrates act on teeth, produce lesions where bacteria get located and dental caries gets produced. To prevent dental caries and to maintain clean and healthy teeth it becomes necessary to use dentifrices. Primary function of dentifrices is to clean the accessible surface of the teeth. There are substances having known therapeutic value. Use of ammoniated tooth paste, urea ammonia containing powders, antibiotic containing mixtures and antienzyme compounds have been in use. These compounds are having their advantages and limitations.
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
Role of Fluoride Role of fluoride in preventing dental caries has been well accepted. Administrations of traces of fluoride having salts or their use in topical use to the teeth have been reported to give encouraging results. Fluoride ion is a trace material which occurs in our body. It is generally adequately obtained from food and water. In some parts of the world, ground water is totally lacking fluoride. In such places occurrence of dental caries has been becoming in alarming proportions. Addition of fluoride to the municipal water supply, known as fluoridation (Note: not fluorination) is able to help in reducing and preventing dental caries. This is not true because those who receive slow continued ingestion of fluoride may suffer from mottling of teeth, increased density of bones, gastric disturbances, muscular weakness, convulsions and even heart failure. Due to beneficial effects in treating dental caries and in some types of osteoporosis, fluorides find use in dental practice. When a fluoride having salt or solution is taken internally, it is readily absorbed, transported and deposited in the bone or developing teeth and remainder gets excreted by the kidneys. The deposited fluoride on the surface of teeth does not allow the action of acids or enzymes in producing lesions. A small quantity (1 ppm) of fluoride thus becomes necessary to prevent caries. However, if more quantity of fluoride (more than 23 ppm) is ingested it is carried to hones and teeth and gives rise to mottled enamel known as dental fluorosis. It is possible to administer fluoride by two routes (i) orally and (ii) topically. The use of fluoridation of public water supply has been the most common and effective way of oral administration. Water supply containing about 0.5 to 1 ppm is provided which is sufficient. Alternatively, it can he given in drinking water or fruit juice in such a concentration to have about 1 ppm per day. Sodium fluoride tablets or solution of sodium fluoride in a dose of 2.2 mg per day are used. For topical application 2 per cent solution is generally used on teeth. Role of Phosphate Besides fluorides, inorganic phosphate salts have been found to he useful reducing the denial caries. Phosphate ions are needed for stronger bones as well as healthy teeth.
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
Phosphate salts both the soluble and insoluble forms are obtained from normal diets. The phosphates are normally given in deficiencies. Role of phosphate as cleaning agent is also important. Sodium fluoride Formula: NaF substance. Preparation: It may be prepared by neutralizing hydrofluoric acid with sodium carbonate. 2HF + Na2CO3 2NaF + H2O + CO2 Another method involves the double decomposition of calcium fluoride with sodium carbonate wherein insoluble calcium carbonate can be removed by filtration. CaF2 + Na2CO3 2NaF + CaCO3 Properties: It forms colorless, odorless crystals or as white powder. It is soluble in water but is insoluble in alcohol. Its aqueous solutions corrode ordinary glass bottles and hence the solution should be prepared in distilled water and stored in dark, pyrex bottles. On acidification of salt solution, hydrofluoric acid is produced. This is weak acid and is poisonous. Aqueous solution of salt yields alkaline reaction. Action and uses: Sodium fluoride due to its fluoride ion is an important agent in dental practice for retarding or preventing dental caries. Sodium Fluoride in 2 per cent aqueous solution is widely used topically; occasionally the solution is applied to the surface of dry teeth periodically over several times inn year. Fluoride ion enters the enamel of teeth and becomes part of enamel structure and thus becomes effective. Approximately 2.2 mg of NaF contains 1 mg of fluoride ion and each g of NaF is equivalent to 23.8 m mol of sodium and fluoride. Sodium fluoride and other soluble fluorides are readily absorbed from GIT. Fluoride also gets absorbed slowly from gums when applied as paste and incorporated into the teeth. Fluoridised teeth have been resistant to microorganisms causing dental caries. It also decreases microbial acid production. Sodium fluoride can he administered as solution, tablet, oral gel or varnish for systemic use or as mouth wash for local use in the mouth. Mol. wt: 41.99 It is having not less than 98.0 per cent of NaF, calculated with reference to the dried
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
A modification of sodium fluoride application is the use of acidified phosphate-sodium fluoride gels. These preparations usually contain the equivalent of approximately 1.23 per cent of fluoride and 1 per cent phosphoric acid. Stannous fluoride Formula: SnF2 water. A fresh solution (about 8.0 per cent) finds use Mot wt: 156.7 in dentistry. Stannous fluoride solution is obtained from using tin fluoride capsules by dissolving in It contains not less than 71.2 per cent of stannous (Sn2+) ions and not less than 22.3 per cent and not more than 25.5 per cent of fluoride, calculated on the dried basis. Properties: It is a white crystalline powder having unpleasant astringent- salty taste. It is soluble in water hut insoluble in alcohol and organic solvents. Aqueous solution of stannous fluoride deteriorates rapidly on standing because of oxidation of stannous cation to stannic form causing turbidity. Thus, stannous fluoride solution must he freshly made. Uses: It is used to prevent dental caries, similar to sodium fluoride and SMFP in the form of solution, gel, mouth wash or dentifrice (toothpaste). It has an unpleasant taste and may cause discoloration of teeth on over-usage. Because of instability of prepared aqueous solutions, fresh solutions are prepared at the time of application. A freshly prepared 8 per cent solution of stannous fluoride is applied to the cleaned dry teeth. A single application has been reported to be sufficient for six to twelve months. Sodium monofluorophosphate U.S.P. It is also known as SMFP. It corresponds to the formula Na2PO3F (mole mass 143.9). It is a white odorless powder. It is freely soluble in water, yielding near neutral solution. It is also used for fluoride supplement of diets (for prevention of caries), fluoridation of municipal water supply and in mouth washes. It is preferred to be included in dentifrices, particularly toothpastes. It is believed SMFP is able to induce better fluoridation of dental enamel and decreases its demineralization, than sodium fluoride.
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
Cleaning Agents or Dentifrices Dentifrice is a material which is used for cleaning of teeth and adjacent gums. One can apply it with finger or preferably with a tooth brush. The main drawback is that it will not be able to clean surfaces inside cavities and crevices between teeth, even if the material reaches them during application. The cleaning action is dependent upon abrasive property and the rubbing force used. Dentifrices are applied as powders or pastes. As brushing teeth with pastes has become a daily practice, some useful substances may be included in dentifrices for providing better oral hygiene and supply of trace materials (e.g. fluoride, antiseptics, deodorants etc.). They may be termed as medicated dentifrices. Flavors and colours are usually added to dentifrice formulations, for improving their acceptance. A good cleaning agent must remove stains from teeth and to achieve this suitable abrasiveness is essential. It becomes difficult to evaluate abrasiveness. Some tests have been designed for this but those are not comparable when tested in vivo. The role of phosphate as anticaries and dentifrice is well-known. Calcium phosphate dibasic and tribasic, sodium metaphosphate are common dentifrice in toothpaste and tooth powders. Similarly, calcium carbonate, pumice powders also serve as dentifrice agents. Calcium carbonate I. P. (See Indian Pharmacopoeia) Precipitated chalk, which is having a fine powdery texture, is used in dentifrices, both powders and pastes. It furnishes both abrasive and antacid effect in the mouth. It forms a common ingredient of tooth powder and toothpaste. Dibasic calcium phosphate I. P. It is also known as dicalcium phosphate or dicalcium orthophosphate or calcium hydrogen phosphate. It occurs as a dihydrate (CaHPO4 2H2O; mole mass 172.09). When exposed to air, it effloresces losing water to form anhydrous dicalcium phosphate (CaHPO4: mole mass 136.06). In a very fine powder form, it finds use in dentifrices. It provides good flow properties and is odourless and tasteless. Its chemistry and properties have been described in greater detail in earlier chapter. Uses. This calcium salt is having 1:1 ratio of calcium to phosphorus. It is most frequently
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
recommended for oral administration as an electrolyte replenisher. As a salt it is able to supply both calcium and phosphorus which is needed for the growth in children, pregnant woman and lactating mothers. Externally it finds use as dentifrice having cleaning action. The moderate abrasive quality makes it suitable for toothpaste and tooth powders. Pumice It is a substance of variable composition consisting of complex silicates of aluminium, potassium and sodium. It is a product obtained from volcanic origin. Properties: It forms odourless, tasteless, very light, hard, grayish-white powder with fineness. It is gritty in nature. It is stable in air and is insoluble in water. On sifting it is categorized into superfine, fine and coarse pumice powder. Uses: Depending upon the particle size it finds use in industry as a filtering and distributing medium. It also finds due to use as abrasive in metal polishes. Due to its grittiness, it is used in soaps and cleaning powders. It forms an ingredient in dental preparation as dental abrasive. Polishing Agents One main requirement of good dentifrice is to have polishing effect on the cleaned teeth. It is possible to achieve the polishing effect by abrasive action. The overall effect provides whiteness to the teeth. Besides, having polishing effect some desensisting agents are added in dentifrices for reducing sensitivity of teeth to heat and cold. The numbing effect is of short duration like that of local anaesthetic. This property is shown by astringent type compounds and due to which they get incorporated in dental products. Desensiting Agents Usually teeth are somewhat sensitive to heat and cold. Especially during teeth decay or in toothache, the perception to heat and cold has been felt strongly. Therefore, some desensiting agents are used in dental preparations so as to reduce sensitivity of teeth to heat and cold.
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
The exact mechanism of action of desensiting agents is not known with certainty. However, they act probably like local anesthetic. Examples of desensiting agents include strontium chloride and zinc chloride. Strontium chloride Formula: SrCl2.6H2O Preparation: It is prepared by adding strontium carbonate to hydrochloric acid until effervescence gets ceased. The solution is filtered, concentrated and allowed to crystallise. Properties: It forms colourless crystals or white granules. It effloresces in dry air. It is soluble in water and alcohol. Uses: It acts as desensitising agent in dental remedies. Strontium chloride is not official in any Pharmacopoeia. Zinc chloride (See Details in Astringents) Formula: ZnCl2 Uses: As discussed earlier, it finds use as a good astringent when used in solution for topical applications. It finds use in 10 per cent solution to be applied to the teeth as desensitising agent. Mouth Washes Mouth washes having zinc sulphate (for its mild antiseptic and astringent action) or zinc chloride (for its deodorant and desensitising action) or potassium permanganate (for its anti-infective and astringent action) or sodium bicarbonate (for its antacid property) or sodium chloride (for irritation) are generally used in dental practice for various reasons. Ammonical silver nitrate solution is also used for its astringent action. It is also able to decrease hypersensitivity of teeth and gums. All these have been described in earlier chapters.
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
QUESTIONS 1. What do you mean by dental hygiene? Broadly classify the products use to maintain dental hygiene. 2. What are Anticaries agents? Give examples. 3. Write down the role of fluoride in preventing dental caries. 4. Write down the role of phosphate as dental product. 5. What are the diseases due to excess of fluorides? 6. Write down the mechanism of action of fluorides and phosphates. 7. Write the preparation of sodium fluoride. 8. Write down the properties of sodium fluoride. 9. Describe briefly various inorganic chemicals used in dental products, their chemistry and specific application in oral hygiene products. 10. Write down the action and uses of sodium fluoride. 11. Write down the properties and uses of stannous fluoride. 12. In what concentration sodium fluoride and stannous fluoride are used as Anticaries agent? 13. Define dentifrices. What are their uses? 14. Dentifrices are not able to clean surfaces inside cavities and crevices between teeth, even if the material reaches them during application. Why? 15. Write down the examples of cleaning agent. 16. Write a short note on calcium carbonate. 17. Describe the method of preparation, uses and assay of: sodium fluoride and dibasic calcium phosphate 18. Give a brief account of fluorides used in dental products. Compare their relative efficacies, advantages and limitations. 19. Describe briefly various inorganic chemicals used in mouth washes, their chemistry and specific applications in oral hygiene products. 20. What are polishing agents? Explain 21. Write short note on desensitizing agents. 22. Write down the uses of zinc chloride in dental preparations. 23. Write a short note on mouth washes. 24. Write notes on the following: a. Sod. Fluoride b. Zinc chloride c. Calcium carbonate d. Stannous fluoride 25. Define: a. Dentifrices b. Anticaries agents c. Desensitizing agents 26. What are anticaries agents? 27. What is the role of fluoride as anticaries?
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DENTAL PRODUCTS
Introduction Dental hygiene has been considered as important since long. In order to maintain dental hygiene, numerous dental products are available in the market. Numerous chemicals find use in their preparation as well as in dentistry. Although it is well known that clean teeth keeps good health and clean teeth cannot decay, it is not possible to clean the teeth continuously all the years. Numerous factors contribute to dental decay and the problem of oral hygiene arises. A large number of inorganic chemicals and their preparations are known which find application in the practice of dental and oral disorders. As they come in contact with the human body, they are regarded like other drugs and pharmaceuticals. Dental products include (i) Anticaries (ii) Cleaning and (iii) Polishing agents. Anticaries Agents Dental caries or tooth decay is more or less a disease of the teeth caused by acids produced by the action of microorganisms on carbohydrates. This disease is characterized by decalcification of tooth accompanied by foul mouth odour. The exact cause and mechanism of dental caries is not known with certainty. However, it is accepted that dental caries first of all starts on the surface of the teeth. Acids produced by bacterial metabolism of fermenting carbohydrates act on teeth, produce lesions where bacteria get located and dental caries gets produced. To prevent dental caries and to maintain clean and healthy teeth it becomes necessary to use dentifrices. Primary function of dentifrices is to clean the accessible surface of the teeth. There are substances having known therapeutic value. Use of ammoniated tooth paste, urea ammonia containing powders, antibiotic containing mixtures and antienzyme compounds have been in use. These compounds are having their advantages and limitations.
1
Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
Role of Fluoride Role of fluoride in preventing dental caries has been well accepted. Administrations of traces of fluoride having salts or their use in topical use to the teeth have been reported to give encouraging results. Fluoride ion is a trace material which occurs in our body. It is generally adequately obtained from food and water. In some parts of the world, ground water is totally lacking fluoride. In such places occurrence of dental caries has been becoming in alarming proportions. Addition of fluoride to the municipal water supply, known as fluoridation (Note: not fluorination) is able to help in reducing and preventing dental caries. This is not true because those who receive slow continued ingestion of fluoride may suffer from mottling of teeth, increased density of bones, gastric disturbances, muscular weakness, convulsions and even heart failure. Due to beneficial effects in treating dental caries and in some types of osteoporosis, fluorides find use in dental practice. When a fluoride having salt or solution is taken internally, it is readily absorbed, transported and deposited in the bone or developing teeth and remainder gets excreted by the kidneys. The deposited fluoride on the surface of teeth does not allow the action of acids or enzymes in producing lesions. A small quantity (1 ppm) of fluoride thus becomes necessary to prevent caries. However, if more quantity of fluoride (more than 23 ppm) is ingested it is carried to hones and teeth and gives rise to mottled enamel known as dental fluorosis. It is possible to administer fluoride by two routes (i) orally and (ii) topically. The use of fluoridation of public water supply has been the most common and effective way of oral administration. Water supply containing about 0.5 to 1 ppm is provided which is sufficient. Alternatively, it can he given in drinking water or fruit juice in such a concentration to have about 1 ppm per day. Sodium fluoride tablets or solution of sodium fluoride in a dose of 2.2 mg per day are used. For topical application 2 per cent solution is generally used on teeth. Role of Phosphate Besides fluorides, inorganic phosphate salts have been found to he useful reducing the denial caries. Phosphate ions are needed for stronger bones as well as healthy teeth.
2
Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
Phosphate salts both the soluble and insoluble forms are obtained from normal diets. The phosphates are normally given in deficiencies. Role of phosphate as cleaning agent is also important. Sodium fluoride Formula: NaF substance. Preparation: It may be prepared by neutralizing hydrofluoric acid with sodium carbonate. 2HF + Na2CO3 2NaF + H2O + CO2 Another method involves the double decomposition of calcium fluoride with sodium carbonate wherein insoluble calcium carbonate can be removed by filtration. CaF2 + Na2CO3 2NaF + CaCO3 Properties: It forms colorless, odorless crystals or as white powder. It is soluble in water but is insoluble in alcohol. Its aqueous solutions corrode ordinary glass bottles and hence the solution should be prepared in distilled water and stored in dark, pyrex bottles. On acidification of salt solution, hydrofluoric acid is produced. This is weak acid and is poisonous. Aqueous solution of salt yields alkaline reaction. Action and uses: Sodium fluoride due to its fluoride ion is an important agent in dental practice for retarding or preventing dental caries. Sodium Fluoride in 2 per cent aqueous solution is widely used topically; occasionally the solution is applied to the surface of dry teeth periodically over several times inn year. Fluoride ion enters the enamel of teeth and becomes part of enamel structure and thus becomes effective. Approximately 2.2 mg of NaF contains 1 mg of fluoride ion and each g of NaF is equivalent to 23.8 m mol of sodium and fluoride. Sodium fluoride and other soluble fluorides are readily absorbed from GIT. Fluoride also gets absorbed slowly from gums when applied as paste and incorporated into the teeth. Fluoridised teeth have been resistant to microorganisms causing dental caries. It also decreases microbial acid production. Sodium fluoride can he administered as solution, tablet, oral gel or varnish for systemic use or as mouth wash for local use in the mouth. Mol. wt: 41.99 It is having not less than 98.0 per cent of NaF, calculated with reference to the dried
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
A modification of sodium fluoride application is the use of acidified phosphate-sodium fluoride gels. These preparations usually contain the equivalent of approximately 1.23 per cent of fluoride and 1 per cent phosphoric acid. Stannous fluoride Formula: SnF2 water. A fresh solution (about 8.0 per cent) finds use Mot wt: 156.7 in dentistry. Stannous fluoride solution is obtained from using tin fluoride capsules by dissolving in It contains not less than 71.2 per cent of stannous (Sn2+) ions and not less than 22.3 per cent and not more than 25.5 per cent of fluoride, calculated on the dried basis. Properties: It is a white crystalline powder having unpleasant astringent- salty taste. It is soluble in water hut insoluble in alcohol and organic solvents. Aqueous solution of stannous fluoride deteriorates rapidly on standing because of oxidation of stannous cation to stannic form causing turbidity. Thus, stannous fluoride solution must he freshly made. Uses: It is used to prevent dental caries, similar to sodium fluoride and SMFP in the form of solution, gel, mouth wash or dentifrice (toothpaste). It has an unpleasant taste and may cause discoloration of teeth on over-usage. Because of instability of prepared aqueous solutions, fresh solutions are prepared at the time of application. A freshly prepared 8 per cent solution of stannous fluoride is applied to the cleaned dry teeth. A single application has been reported to be sufficient for six to twelve months. Sodium monofluorophosphate U.S.P. It is also known as SMFP. It corresponds to the formula Na2PO3F (mole mass 143.9). It is a white odorless powder. It is freely soluble in water, yielding near neutral solution. It is also used for fluoride supplement of diets (for prevention of caries), fluoridation of municipal water supply and in mouth washes. It is preferred to be included in dentifrices, particularly toothpastes. It is believed SMFP is able to induce better fluoridation of dental enamel and decreases its demineralization, than sodium fluoride.
4
Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
Cleaning Agents or Dentifrices Dentifrice is a material which is used for cleaning of teeth and adjacent gums. One can apply it with finger or preferably with a tooth brush. The main drawback is that it will not be able to clean surfaces inside cavities and crevices between teeth, even if the material reaches them during application. The cleaning action is dependent upon abrasive property and the rubbing force used. Dentifrices are applied as powders or pastes. As brushing teeth with pastes has become a daily practice, some useful substances may be included in dentifrices for providing better oral hygiene and supply of trace materials (e.g. fluoride, antiseptics, deodorants etc.). They may be termed as medicated dentifrices. Flavors and colours are usually added to dentifrice formulations, for improving their acceptance. A good cleaning agent must remove stains from teeth and to achieve this suitable abrasiveness is essential. It becomes difficult to evaluate abrasiveness. Some tests have been designed for this but those are not comparable when tested in vivo. The role of phosphate as anticaries and dentifrice is well-known. Calcium phosphate dibasic and tribasic, sodium metaphosphate are common dentifrice in toothpaste and tooth powders. Similarly, calcium carbonate, pumice powders also serve as dentifrice agents. Calcium carbonate I. P. (See Indian Pharmacopoeia) Precipitated chalk, which is having a fine powdery texture, is used in dentifrices, both powders and pastes. It furnishes both abrasive and antacid effect in the mouth. It forms a common ingredient of tooth powder and toothpaste. Dibasic calcium phosphate I. P. It is also known as dicalcium phosphate or dicalcium orthophosphate or calcium hydrogen phosphate. It occurs as a dihydrate (CaHPO4 2H2O; mole mass 172.09). When exposed to air, it effloresces losing water to form anhydrous dicalcium phosphate (CaHPO4: mole mass 136.06). In a very fine powder form, it finds use in dentifrices. It provides good flow properties and is odourless and tasteless. Its chemistry and properties have been described in greater detail in earlier chapter. Uses. This calcium salt is having 1:1 ratio of calcium to phosphorus. It is most frequently
5
Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
recommended for oral administration as an electrolyte replenisher. As a salt it is able to supply both calcium and phosphorus which is needed for the growth in children, pregnant woman and lactating mothers. Externally it finds use as dentifrice having cleaning action. The moderate abrasive quality makes it suitable for toothpaste and tooth powders. Pumice It is a substance of variable composition consisting of complex silicates of aluminium, potassium and sodium. It is a product obtained from volcanic origin. Properties: It forms odourless, tasteless, very light, hard, grayish-white powder with fineness. It is gritty in nature. It is stable in air and is insoluble in water. On sifting it is categorized into superfine, fine and coarse pumice powder. Uses: Depending upon the particle size it finds use in industry as a filtering and distributing medium. It also finds due to use as abrasive in metal polishes. Due to its grittiness, it is used in soaps and cleaning powders. It forms an ingredient in dental preparation as dental abrasive. Polishing Agents One main requirement of good dentifrice is to have polishing effect on the cleaned teeth. It is possible to achieve the polishing effect by abrasive action. The overall effect provides whiteness to the teeth. Besides, having polishing effect some desensisting agents are added in dentifrices for reducing sensitivity of teeth to heat and cold. The numbing effect is of short duration like that of local anaesthetic. This property is shown by astringent type compounds and due to which they get incorporated in dental products. Desensiting Agents Usually teeth are somewhat sensitive to heat and cold. Especially during teeth decay or in toothache, the perception to heat and cold has been felt strongly. Therefore, some desensiting agents are used in dental preparations so as to reduce sensitivity of teeth to heat and cold.
6
Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
The exact mechanism of action of desensiting agents is not known with certainty. However, they act probably like local anesthetic. Examples of desensiting agents include strontium chloride and zinc chloride. Strontium chloride Formula: SrCl2.6H2O Preparation: It is prepared by adding strontium carbonate to hydrochloric acid until effervescence gets ceased. The solution is filtered, concentrated and allowed to crystallise. Properties: It forms colourless crystals or white granules. It effloresces in dry air. It is soluble in water and alcohol. Uses: It acts as desensitising agent in dental remedies. Strontium chloride is not official in any Pharmacopoeia. Zinc chloride (See Details in Astringents) Formula: ZnCl2 Uses: As discussed earlier, it finds use as a good astringent when used in solution for topical applications. It finds use in 10 per cent solution to be applied to the teeth as desensitising agent. Mouth Washes Mouth washes having zinc sulphate (for its mild antiseptic and astringent action) or zinc chloride (for its deodorant and desensitising action) or potassium permanganate (for its anti-infective and astringent action) or sodium bicarbonate (for its antacid property) or sodium chloride (for irritation) are generally used in dental practice for various reasons. Ammonical silver nitrate solution is also used for its astringent action. It is also able to decrease hypersensitivity of teeth and gums. All these have been described in earlier chapters.
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Inorganic Medicinals Department of Pharmaceutical Sciences, BIT Mesra, Ranchi
QUESTIONS 1. What do you mean by dental hygiene? Broadly classify the products use to maintain dental hygiene. 2. What are Anticaries agents? Give examples. 3. Write down the role of fluoride in preventing dental caries. 4. Write down the role of phosphate as dental product. 5. What are the diseases due to excess of fluorides? 6. Write down the mechanism of action of fluorides and phosphates. 7. Write the preparation of sodium fluoride. 8. Write down the properties of sodium fluoride. 9. Describe briefly various inorganic chemicals used in dental products, their chemistry and specific application in oral hygiene products. 10. Write down the action and uses of sodium fluoride. 11. Write down the properties and uses of stannous fluoride. 12. In what concentration sodium fluoride and stannous fluoride are used as Anticaries agent? 13. Define dentifrices. What are their uses? 14. Dentifrices are not able to clean surfaces inside cavities and crevices between teeth, even if the material reaches them during application. Why? 15. Write down the examples of cleaning agent. 16. Write a short note on calcium carbonate. 17. Describe the method of preparation, uses and assay of: sodium fluoride and dibasic calcium phosphate 18. Give a brief account of fluorides used in dental products. Compare their relative efficacies, advantages and limitations. 19. Describe briefly various inorganic chemicals used in mouth washes, their chemistry and specific applications in oral hygiene products. 20. What are polishing agents? Explain 21. Write short note on desensitizing agents. 22. Write down the uses of zinc chloride in dental preparations. 23. Write a short note on mouth washes. 24. Write notes on the following: a. Sod. Fluoride b. Zinc chloride c. Calcium carbonate d. Stannous fluoride 25. Define: a. Dentifrices b. Anticaries agents c. Desensitizing agents 26. What are anticaries agents? 27. What is the role of fluoride as anticaries?
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