Tooth Pastes - Industrial pharmacy - I B. Pharma 5th Semester PDF Notes

Tooth Pastes

Contents

• Tooth paste

• Formulation aspects

• Manufacturing of tooth paste

• Packaging and evaluation of dentifrices

Learning objectives

• At the end of this lecture, student will be able to:

– Explain the formulation of tooth paste

– Explain the manufacturing of tooth paste

– Discuss on packaging and evaluation of dentifrices

Dentifrices

• The tooth is composed of calcium, phosphorus, and other mineral salts

• The hard, shiny and outermost layer visible is called the enamel

• Dentifrices are hygienic preparations intended to cleanse the teeth, keep them shiny and to preserve the health of teeth

• Though the primary function of a dentifrice is the cleaning of the accessible surfaces of the teeth, some other functions include:

– Prevention of formation of dental plaque

– Prevention of formation of calculus

– Polishing of tooth

– Removal of stains

– Reduction of periodontal disease

Parts of tooth

Types of Dentifrices

• Tooth powder

• Tooth paste

Ideal properties of good dentifrices

• It must adequately clean teeth of stain, food, debris and plaque

• It must remove bad odour of mouth cavity and should leave sensation of cleanliness and freshness in mouth sensation of cleanliness and freshness in mouth

• It should be non-toxic

• It should be pleasant and provide good flavour in oral cavity as an after effect

• It must be easy to use

• It must reduce the teeth decay

• It should not damage tooth enamel because of its abrasiveness

• It should be economic

Tooth paste

• Tooth pastes contain several ingredients such as

– Abrasives and polishing materials

– Detergents and foaming materials

– Humectants

– Binding agents

– Sweetening materials

– Flavors

– Preservatives

– Miscellaneous or special ingredients such as

Anti caries agents

Anti-bacterial agent

Desensitizing agent

Whitening agent etc.

Abrasives and polishing materials

• Abrasiveness depends on the inherent hardness of abrasive, size, and shape of abrasive particle

• Other factors that may affect abrasiveness are:

– Brushing technique,

– The pressure on the toothbrush,

– The hardness of the bristles,

– Direction and number of strokes

• Excess abrasion may cause damage to tooth surface tooth enamel erosion

Detergents and foaming materials

• The cleansing action of the detergents is due to their lowering of surface tension

• They help in wetting the teeth which aids in removal of debris

• Sodium lauryl sulphate is one of them most widely used

• Others are magnesium lauryl sulphates, sodium lauryl sarcosinate, and diethyl sodium lauryl sulphosuccinate

Sweetening agents

• Sweetening agent is an essential ingredient

• Sodium Saccharine and xylitol is a widely used sweetening agent

• It is used in 0.05 to 0.31%

Flavouring agents

• Flavours are incorporated to provide a good flavour and to have a long term effect in the mouth

• Commonly used are peppermint oil, spearmint oil, anise oil, Clove oil, winter green oil

Humectants

• Humectants are added to maintain moisture and impart some plasticity character to the toothpaste

• They prevent drying out of toothpaste

• Usually added in concentration of 10-30%

• They aid in subsequent hardening of the product upon exposure to air

• Sugar and honey were used previously.

• Commonly used are Saccharin, sorbitol, xylitol, mannitol, propylene glycol and Glycerin

• Sorbitol – also known as glucitol, is commonly used in modern cosmetics as a humectant and thickener

• Transparent gel can be made using sorbitol

• Xyitol – also called as wood sugar, is a naturally occurring sweetening agent found in the fibers of many fruits and vegetables including berries, corn, husks, oats and mushrooms

• They aid in repairing minor cavities caused by dental caries

Binding agents

• Various hydrocolloids are used in tooth pastes to improve and maintain the consistency

• These hydrocolloids are used in 2-5%.

• Initially starch, liquid glucose and simple syrup were used

• But slowly they were replaced by mucilages, karaya gum, gum arabic, gum acacia, tragacanth, and sodium alginate

Preservatives

• Preservatives are added to prevent bacterial growth

• Commonly used are methyl and para parahydroxy benzoate (parabens) in range of 0.15%-0.02%

Colouring agents

• FD & C approved colours and opacifiers like titanium dioxide, zinc oxide are used

Miscellaneous or special ingredients

• Anti caries agents

• Anti-bacterial agent

• Desentizing agent

• Whitening agent

Miscellaneous or special ingredients

Anti-Caries / Cavity Protection	Sodium fluoride sodium monofluorophosphate	contain fluoride to stop tooth enamel decalcification and protect teeth from tooth decay and cavities	Eg. Colgate cavity protection
Anti-bacterial (Plaque & Gingivitis Prevention)	Sodium Lauryl Sulphate, Triclosane, Zinc and Stannous ions	Antibacterial and prevent the formation of dental plaque.	Eg. Crest-pro- health clinical gum protection
Desentizing	Potassium nitrate, sodium chloride	Reduces the  sentivity of teeth to hot and cold	Eg: Sensodyne
Tooth Whitening	Papain, Dimethicone Charcoal	Have either higher abrasion value than normal toothpastes to mechanically remove food, smoking and other stains from teeth.	Eg. Colgate Optical White and Colgate Pro-clinical White.

Manufacturing of Tooth Paste

First method

• Binder is wetted by humectant it’s then dispersed in liquid portion containing saccharine and preservative

• Its allowed to swell untill a homogeous mass or gel is obtained

• Flavours an detergents are added and mixed well

• The paste is then milled, cleavated and tubed

Second method

• Binder is premixed with solid abrasive

• Its then dispersed in liquid portion containing humectant, saccharine and preservative

• Its allowed to swell untill a homogeous mass or gel is obtained

• Flavours an detergents are added and mixed well

• The paste is then milled, cleavated and tubed

Packaging of dentifrices

• Tin coated lead tubes were used

• Aluminium tubes being light and strong are used commonly

• Corrosion of aluminium tubes is minimized by internally waxing or lacquering the tubes

• Inhibitors of corrosion such as sodium silicate is added

• Paste containing stannous fluoride should not be packed in aluminium tubes

• Polyolefins collapsible tubes are also used

Evaluation of Dentifrices

• Dentifrices are evaluated

– Abrasiveness

– Particle size

– Cleaning property

– Foaming property

– pH

– Consistency

Determination of abrasive particles

• The paste was extruded about 15 to 20 cm length from collapsible tube of each sample on a butter paper

• Then all the samples were tested by pressing it along its entire length by a finger for the presence of hard and sharp edged abrasive particles for all samples

Determination of spread ability

• About 1 gm of each sample was weighed and placed at the centre of the glass plate (10X10 cm) and another glass plate was placed over it carefully

• Above the glass plates 2 kilogram weight was placed at the centre of the plate avoid sliding of the plate

• The diameter of the paste in centimeters was measured, after 30 minutes for all samples

• The experiment was repeated three times and the averages were reported for all samples

Determination of fineness

• 10gm of each sample was accurately weighed and placed in a 100ml beaker

• To this 50ml of water was added and allowed to stand for 30 mins with occasional stirring until the toothpaste was completely dispersed

• This solution was passed through to 150 micron Indian Standard sieve

• Then the sieve was washed with running tap water

• Washing should be continued until all the matters passed by through the sieve

• After washing the residue remains on sieves were collected and dried in an oven at 105°C

Determination of pH

• 5 gm of all samples was accurately weighed and placed in a 150 ml beaker

• To this 45 ml of freshly boiled and cooled water was added at 27°C

• It was stirred well to make a thorough suspension

• The pH was determined for all samples within 5 minutes by using pH meter

Determination of foaming power

• About 5gm of each sample was weighed and placed in a 100ml glass beaker

• To this 10ml of water was added and the beaker was covered with a watch glass and allowed to stand for 30 minutes, this operation was carried out to disperse the toothpaste in water

• The contents of the beaker were stirred with a glass rod and the slurry was transferred to a 250ml graduated measuring cylinder, during this transfer ensure that no foam was produced and no lump paste went into the measuring cylinder

Summary

Constituent	Purpose
Abrasive	Cleaning/stain removal
Water	Solvent for ingredients
Humectants	Provide creamy texture
Detergent	Surfactant/foam builder
Thickening agent	Controls viscosity
Flavoring agent,	Enhances flavour
Sweetening agent	Improves taste
Colouring agent	Imparts colour
Therapeutic agent(s)	Active ingredient(s)
Preservative	Inhibits microbial growth
Binder	Holds ingredients together

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