Dental Products Sample Assignment

DENTAL PRODUCTS

Dentifrices, role of fluoride in the treatment of dental caries, Desensitizing agents, Calcium carbonate, Sodium fluoride, and Zinc Eugenol cement

SCOPE

This chapter deals with the monographs of inorganic drugs and pharmaceuticals.

OBJECTIVES

Upon completion of this Assignment one shall be able to:

Know the types of dentifrices as inorganic drugs and pharmaceuticals also understand the medicinal and pharmaceutical importance of inorganic dental compounds

INTRODUCTION

The teeth are accessory digestive organs. People use their teeth to bite and chew food, the first step in the digestion of food. The long, sharp canine teeth tear up food (like meat). The wide, flat molars grind and mash up food. While we chew food, the tongue pushes the food to the teeth and saliva helps digestion and wets the food. A number of inorganic compounds are used in maintaining the oral and dental hygiene. Most of them are over the counter (OTC) products. Dental products include:

1. Anticaries agents
2. Polishing agents
3. Desensitizing agents

1. ANTICARIES AGENTS

Dental caries, or tooth decay, involves a gradual demineralization (softening) of the enamel and dentin. If it is not treated then microorganisms may invade the pulp, causing inflammation and infection, with subsequent death of the pulp and abscess of the alveolar bone surrounding the root’s apex, requiring root canal therapy. Dental cavities are formed by the growth and implantation of cariogenic microorganisms.

1. Bacteria (primarily Streptococcus mutans and lactobacillaceae) produce acids, mostly lactic acid that demineralize the enamel. The demineralized enamel initially appears as a white, chalky area and eventually becomes brown or yellow.
2. Diet is another factor in the development of dental caries. Diet with a high concentration of fermentable carbohydrates increases the risk of dental caries.
3. Masses of bacterial cells, sticky polysaccharide (produced from sucrose) and other debris adhering to teeth constitute dental plaque.

The formation of bacterial plaque also helps the decay process by forming pockets or crevices on the tooth surface in which the food particles can stick and be decayed by the bacteria. If plaque is not removed it calcifies into calculus when calcium salt precipitates from the saliva.

Preventive Measures

1. Dentifrices can prevent the dental caries and also maintain oral and dental hygiene. These are the products that enhance the removal of stain and dental plaque by the toothbrush.
2. Administration of fluoride is the most accepted approach to prevent caries includes flossing and brushing.

(i) Dentifrices

Dentifrices are the materials which are used for cleaning/polishing/filling 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 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). They may be termed as medicated dentifrices. Flavors and colors 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.

The role of fluoride, phosphate as anticaries agent and dentifrice is well-known. Calcium phosphate dibasic and dibasic sodium metaphosphates are common dentifrice in toothpaste and tooth powders. Similarly, calcium carbonate, pumice powders also serve as dentifrice agents.

(ii) Role of Fluoride

Role of fluoride in preventing dental caries has been well accepted. Fluoride is anticariogenic as it replaces the hydroxyl ion in hydroxyapatite with the fluoride ion to form fluorapatite in the outer surface of the enamel. Fluorapatite hardens the enamel and makes it more acid resistant. Fluorapatite has also shown antibacterial activity. Fluoride is most beneficial up to an age of 12 or 13 because unerupted permanent teeth are mineralizing during that time. 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 2-3 ppm) is ingested it is carried to bones 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 the useful reducing the denial caries. Phosphate ions are needed for stronger bones as well as healthy teeth. 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.

2. POLISHING AGENTS

Dentifrices contain agents for cleaning tooth surfaces and providing polishing effect on the cleaned teeth. These agents are abrasive in nature. They are responsible for physically removing plaque and debris. Besides, having polishing effect some desensitizing 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 anesthetic. This property is shown by astringent type compounds and due to which they get incorporated in dental products. Examples include dicalcium phosphate, sodium metaphosphate, calcium pyrophosphate, calcium carbonate and calcium monohydrogen phosphate. Pumice is too abrasive for daily use in a dentifrice.

3. DESENSITIZING 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 desensitizing agents are used in dental preparations so as to reduce sensitivity of teeth to heat and cold.

4. OFFICIAL COMPOUNDS

(i) Sodium fluoride

Formula: NaF Mol. wt: 41.99

It is having not less than 98.0 per cent of NaF, calculated with reference to the dried substance. Preparation: It may be prepared by neutralizing hydrofluoric acid with sodium carbonate.

Another method involves the double decomposition of calcium fluoride with sodium carbonate wherein insoluble calcium carbonate can be removed by filtration.

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 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. Fluoridated 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.

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.

(ii) Stannous fluoride

Formula: SnF₂ Mot wt: 156.7

Stannous fluoride solution is obtained from using tin fluoride capsules by dissolving in water. A fresh solution (~ 8.0 %) finds use in dentistry. 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 but insoluble in alcohol and organic solvents. Aqueous solution of stannous fluoride deteriorates rapidly on standing because of oxidation of stannous ion to stannic ion form causing turbidity. Thus, stannous fluoride solution must he freshly made.

Uses: It is used to prevent dental caries, similar to sodium fluoride 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.

(iii) 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.

(iv) Calcium carbonate I. P.

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 calcium hydrogen phosphate dehydrate salt (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 odorless and tasteless.

Uses. This calcium salt is having 1:1 ratio of calcium to phosphorus. It is most frequently 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.

(V) DISINFECTANTS

Disinfectants are antimicrobial agents that are applied to non-living objects to destroy microorganisms. The process is known as disinfection. Disinfectants are different from antibiotics and antiseptics in that, antibiotics, destroy microorganisms within the body, and antiseptics, destroy microorganisms on living tissue. Bacterial endospores are most resistant to disinfectants, however some bacteria and viruses also possess some tolerance. A perfect disinfectant produces complete sterilization, without causing any harm to other forms of life, is inexpensive, and non-corrosive. Unfortunately, there is no ideal disinfectant. Most disinfectants are also, by their very nature, potentially harmful (even toxic) to human beings. They should be treated with appropriate care. Most of them come with safety instructions printed on the packaging, which should be read completely before using the disinfectant. They are frequently used in hospitals and dental surgeries; to kill infectious organisms. The selection of the disinfectant to be used is made according to the particular situation. Some disinfectants kill a wide range (kill nearly all microorganisms), while others kill a smaller range of disease-causing organisms but are preferred for other properties (that may be non-corrosive, non-toxic, or inexpensive).

(vi) Zinc-Eugenol Cement

Preparation

Zinc-Eugenol cement consists of two parts and is prepared as follows:

Part A

The Powder: Zinc Acetate 0.5 g Zinc Stearate 1 g Zinc Oxide 70 g Rosin 27.5 g Rosin is powdered and mixed with about an equal weight of zinc oxide. The mixture is sifted through a sieve of not less than 100–mesh. The material retained on the sieve is regrinded with additional zinc oxide, and sifted again. The process of regrinding and sifting is repeated until all of the material passes readily through the sieve and the two mixtures are then mixed with the remainder of the zinc oxide.

Part B

The Liquid: Eugenol 85 ml Cottonseed Oil 15 ml the liquids are mixed together in the proportion specified. Zinc-Eugenol cement is prepared by mixing 10 parts of the powder with 1 part of the liquid to a thick paste immediately before use. For obtaining any desired consistency the amount of the liquid may be varied.

The Powder Identification Tests:

1. 10 parts of the powder is mixed with 1 part of the liquid and the resulting mixture is transferred to a beaker containing water at 25^oC. The mixture hardens in not more than 20 minutes.
2. 1 g of the powder is triturated with 10 ml of solvent hexane. The mixture is filtered and to the filtrate 10 ml of freshly prepared cupric acetate solution (1 in 200) is added, shaken for a few minutes, and allowed the liquid layers to separate. The solvent hexane layer is green.
3. The residue obtained in the assay for total zinc as zinc oxide, dissolved in a slight excess of hydrochloric acid, gives reactions for zinc.
4. 5 g of the powder is triturated with 25 ml of water, the triturate is filtered and to 10 ml of the clear filtrate, 1 ml of ferric chloride TS is added in a color comparison tube. A standard is prepared by adding 1 ml of ferric chloride TS to 10 ml of water in a matched color-comparison tube. The intensity of the color produced in the filtrate is more than that of standard color when viewed downwards against a white surface.
5. Assay for Rosin: About 1 g of the accurately weighed powder is placed in a beaker, to this 50 ml of chloroform is added, and stirred for several minutes. The resultant is filtered through a tarred porcelain filtering crucible and the insoluble material is transferred as completely as possible with additional portions of chloroform. The crucible is washed with chloroform, dried in an oven at 80°C, cooled, and weighed. The loss in weight of the powder taken should not be less than 300 mg.
6. Assay for total Zinc as Zinc oxide: Ignite the residue obtained in the assay of rosin to constant weight, cool, and weigh. The weight of the ZnO so obtained is not less than 680 mg and not more than 720 mg. The Liquid Identification Test: 1 ml of the liquid is shaken with 20 ml of water, filtered, and to 5 ml of the clear filtrate, 1 drop of ferric chloride TS is added. A transient pale yellow-green color is produced.
7. Specific Gravity: Between 1.043 and 1.048.
8. Refractive Index: Between 1.528 and 1.531 at 20°

Uses: It is temporary cement with a zinc oxide Eugenol base for crown and bridge procedures. It can be used in dentistry as a filling or cement material. It is used in temporary restorations, in managing dental caries as a temporary filling. It is also used as an impression material during construction of complete dentures.

Zinc-Eugenol cement has anesthetic and antimicrobial effect due to the eugenol content and is used in painful conditions of dental pulp.

Table: 1 Official Compounds Used as Dental Products

Table: 2 Plant Products Used as the Dental Products

VI IMPORTANT TERMS

Abrasive: a substance or material such as sandpaper, pumice, or emery, used for cleaning, grinding, smoothing, or polishing.

Acidification: to become an acid or to make something become an acid.

Anesthetic: a substance that induces insensitivity to pain.

Anticariogenic: are the substances that inhibit or arrest dental caries formation.

Antiseptics: are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction.

Astringent: causing the contraction of skin cells and other body tissues.

Calcifies: hardens by deposition of or conversion into calcium carbonate or some other insoluble calcium compounds.

Carbohydrates: any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body.

Convulsions: a sudden, violent, irregular movement of the body, caused by involuntary contraction of muscles and associated especially with brain disorders such as epilepsy, the presence of certain toxins or other agents in the blood, or fever in children.

Corrosive: tending to cause corrosion.

Demineralization: is a process in which, the enamel starts losing its minerals and begins to crumble.

Dental Caries: is a multifactorial microbial infectious disease characterized by demineralization of the inorganic and destruction of the organic substance of the tooth.

Dental Plaque: is defined as the soft deposits that form the bio film adhering to the tooth surface. Plaque is composed of organic, inorganic materials derived from saliva, gingival crevicular fluid & bacterial products.

Desensitizing Agents: are defined as drugs that alleviate painful. sensations that sometimes occur in exposed dentin and cementum.

Enamel: an opaque or semi-transparent glossy substance that is a type of glass, applied by vitrification to metallic or other hard surfaces for ornament or as a protective coating.

Endospores: a resistant asexual spore that develops inside some bacteria cells.

Fermentation: the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat.

Flossing: clean between (one's teeth) with dental floss.

Hydroxyapatite: a mineral related to apatite which is the main inorganic constituent of tooth enamel and bone, although it is rare in rocks.

Hygiene: conditions or practices conducive to maintaining health and preventing disease, especially through cleanliness.

Microorganisms: a microscopic organism, especially a bacterium, virus, or fungus.

Molars: a grinding tooth at the back of a mammal's mouth.

Mottling: mottling of enamel is a chronic endemic form of hypoplasia of the dental enamel caused by drinking water with high fluoride content when a child is in the time of tooth formation.

Numbing: depriving one of feeling or responsiveness.

Osteoporosis: a medical condition in which the bones become brittle and fragile from loss of tissue, typically as a result of hormonal changes, or deficiency of calcium or vitamin D.

Polishing Agents: An abrasive used to achieve a smooth, lustrous finish to a tooth surface

Polysaccharide: are polymeric carbohydrate molecules composed of long chains of monosaccharide units bound together by glycoside linkages, and on hydrolysis give the constituent monosaccharide or oligosaccharide. They range in structure from linear to highly branch.

Pyrex: a hard heat-resistant type of glass, typically used for ovenware.

Replenished: to make full or complete again, as by supplying what is lacking, used up, etc.

Root Canal Therapy: also known as endodontic treatment, is a dental procedure in which the diseased or damaged pulp (core) of a tooth is removed and the inside areas (the pulp chamber and root canals) are filled and sealed.

Turbidity: Turbidity is the cloudiness or haziness of a fluid caused by suspended solids that are usually invisible to the naked eye.

VII COMMONLY COMPOUNDED DENTAL MEDICATIONS

1. Analgesics
2. Antivirals
3. Antibiotics
4. Topical Anesthetics
5. Sedatives
6. Dry Socket Mixtures
7. Root Canal Paste
8. Plaque Removal Solutions
9. Oral Rinses
10. Adhesives
11. Bleaching Gels
12. Crown Preps
13. Combination mouth rinses for oral ulcers containing a combination of antibiotics, antihistamines, antifungals, anesthetics, corticosteroids, misoprostol
14. Transdermal pain gels for neuralgias and temporomandibulary joint disorders (TMJ)
15. Dry Mouth Treatments

VIII KEY POINTS

• The teeth are accessory digestive organs.
• Dental products include Anticaries agents, Polishing agents, and Desensitizing agents.
• Dental cavities are formed by the growth and implantation of cariogenic microorganisms.
• Dentifrices can prevent the dental caries and also maintain oral and dental hygiene.
• Administration of fluoride is the most accepted approach to prevent caries includes flossing and brushing.
• Fluoride is anticariogenic as it replaces the hydroxyl ion in hydroxyapatite with the fluoride ion to form fluorapatite in the outer surface of the enamel.
• Phosphate ions are needed for stronger bones as well as healthy
• Disinfectants are different from antibiotics and antiseptics as they are applied to non-living objects to destroy microorganisms.

VII REFERENCES

1. Becket & Stenlake. Practical Pharmaceutical Chemistry. Vol. 1& 2. 4th edition, 2005. CBS Publishers, New Delhi.
2. M. Verma. Analytical Chemistry. IIIrd edition, 2007. CBS Publishers, New Delhi.
3. M. Atherden, Bentley and Driver's Textbook of Pharmaceutical Chemistry, Oxford University Press, Delhi (Latest Edition).
4. Anand & Chatwal, Inorganic Pharmaceutical Chemistry.
5. Indian Pharmacopoeia