We all want to have bright smiles with clean and healthy teeth. Stained and discoloured teeth give a very ugly appearance. So we must have sufficient knowledge about TOOTH STAINING to avoid any discoloration of the teeth.

There are various reasons of stained teeth. Basically, stains on the teeth are broadly divided two types

Extrinsic Staining i.e. Staining on the surface of the tooth

Intrinsic Staining i.e. Staining inside the tooth.

Extrinsic Staining

This types of staining or discoloration of teeth is present only on the outer surface of the tooth. These types of stained teeth are because of consumption of coffee, tea, cold drinks, red wine and other types of food and drinks and smoking. These stained teeth can be because of deposition of plaque also. Treatment of this type of stained teeth is the use of proper brushing and cleaning from dentist. However some extrinsic stains get embedded into the tooth due to prolonged use of tobacco products & smoking. These teeth needs tooth whitening /bleaching from the dentist.

The various CAUSES of extrinsic staining are further divided into these subtypes:-

1. Direct staining
2. Indirect staining

Now lets get to know about each one of them.

Direct Extrinsic Staining

There are various polyphenolic compounds present in the food that we eat. These compound are believed to give the external discoloration to the tooth. When we consume food, there are various chromogens that are taken up by the pellicle present along the tooth surface which imparts colour to the tooth surface. Various beverages like tea, coffee and habits like tobacco chewing, smoking causes staining of the teeth.

Indirect Extrinsic Staining

In this type of staining, the agent that causes staining is usually colourless or of a different colour from that of the extrinsic tooth stain. It is associated with cationic antibiotics and metal salts.

Another subtype for better understanding of the topic is:

A. Non-Metallic staining

B. Metallic staining

A. Non-Metallic Staining

The plaque or acquired pellicle present along the tooth surface adsorb the various non-metallic extrinsic tooth stains. The various causative agents are dietary components, mouthrinses, beverages, medicaments, tobacco etc. The prolonged use of various mouthwashes like chlorhexidine, various quaternary ammonium compounds in mouthwashes cause extrinsic staining of the teeth.

The pic below shows satining to the teeth due to prolonged use of chlorhexidine mouthwash.

B. Metallic Staining

This type of tooth staining is caused due to occupational exposure to different metals or because of consumption of medicines containing various metallic salts. Metals cause a very characteristic staining to the teeth like iron causes black stains, copper causes green stains, potassium permangenate causes violet to black coloured stains, silver nitrate causes grey stains, stannous fluoride causes golden brown discoloration etc.

Intrinsic Staining

The colour of a tooth is determined by the colour of the dentine which is transmitted through the transparent enamel. Any change in the structural composition or thickness of the tooth structure leads to discoloration of the tooth known as

Intrinsic Staining

This type of staining can be hereditary or because of certain systemic factors, metabolic factors, trauma to the tooth or medications which are consumed when the teeth are developing e.g. tetracycline which is an antibiotic. Fluorosis which is because of high consumption of fluoride also causes intrinsic dental staining. The treatment of these types of stained teeth is either bleaching also called walking bleach done by dentist. If the teeth does not get whitened to patient satisfaction, then one can go for Veneers or other cosmetic treatments e.g. crowns, tooth colored restorations from the dentist.

Few CAUSES of intrinsic staining are as follows

Alkaptonuria: In this condition the teeth become brownish in colour. It is an in born error that leads to incomplete metabolism of tyrosine and phenylanine, which further results in the formation of homogentistic acid.

Amelogenesis imperfecta: It is a hereditary condition, mostly autosomal dominant. The enamel in this condition is hard and has yellow to yellowish brown colour. The mineralisation or matrix formation during amelogenesis (formation of enamel) is disturbed leading to discolouration of the tooth. It has further 14 subtypes and the colour changes are according to the severity of extent of the condition.

Congenital erythropoietic porphyria: In this there is error in porphyrin metabolism which is due to deposition of porphyrin in teeth, bone marrow, red blood cells, urine, faeces etc. It is an autosomal recessive disorder. The colour of the teeth changes to reddish brown but it is a rare finding.

Dentinogenesis imperfecta: The colour of the tooth changes to bluish or brown in this condition. The pulp chambers become obliterated and rapid wear takes place of the dentine. The enamel begins to chipoff, exposing the dentino-enamel junction(DEJ) As the dentine gets exposed, the teeth start appearing brown in colour. Various genetic reasons, systemic disorders and environmental factors lead to formation of these dental defects in the tooth.

Tetracycline staining Tetracycline affected teeth give a brownish grey or yellowish appearance. This colour changes to brown with age. This type of intrinsic staining is caused by systemic administration of tetracycline during development of the teeth, which leads to its deposition on teeth and bones. Tetracycline can across the placental barrier so it should be avoided in expectant females, lactating mothers and in growing children.

Congenital hyperbilirubinaemiaIn this type there is a yellowish green discoloration due to breakdown products of haemolysis.

Fluorosis: The colour of the enamel may vary from chalky white to dark brown or black. It is caused by excessive intake of fluorides. The various sources are drinking water, toothpastes, mouthwashes or tablets. The severity of the tooth staining may vary according to the age and the dose of flouride intake.  

Enamel Hypoplasia: In this condition there are pits or grooves formed on the surface of enamel. It has both LOCALISED and GENERALISED causes. The local causes include any infection of the deciduous dentition or any trauma to the milk or primary teeth. Both the cases affect the permanent tooth germ lying below the deciduous tooth, leading to its hypoplasia.

The generalised factors for enamel hypoplasia include maternal vit.D deficiency, rubella infection, hypocalcaemia or intake of various drugs during pregnancy.

The picure below shows localised enamel hypoplasia in both maxillary central incisors.

Pulpal haemorrhagic products:The colour of the tooth changes to purplish pink in this condition. Any severe trauma to the tooth causes hemolysis(breakdown) of the red blood cells leading to formation of black iron sulfide.

Root resorption:The most initial colour change is the pinkish discolouration along the cemento-enamel junction(CEJ) Root resortion always begins at the root surface. If it begins at the pulpal aspect it is known as INTERNAL ROOT RESORTION. And if it begins at the periodontal aspect it is known as EXTERNAL ROOT RESORTION. Root resorption is asymptomatic clinically.

Ageing: As a person ages, secondary dentine gets deposited on the tooth surface. The enamel becomes thinner with age, thus reflecting more colour of the darkened dentine. This causes further darkening of the colour of the tooth with age. The pic below shows loss of enamel structures because of the wearing of the teeth(attrition) due to age. This leads to exposure of the dentine.

Treatment

The best treatment available for tooth discolouration or staining is tooth whitening. Tooth whitening is best achieved by PROFESSIONAL BLEACHING.

Method: The dentist will first take a detailed history of the patient to find the cause and type of tooth discolouration. A comparision is then made between the colour of the teeth and the desired shade of the teeth using a shade guide. Then a custom made tray(mouthguard) is made according to the dental status and oral cavity of the patient. This tray is made to nicely fit along the teeth. The gingiva is protected with petroleum jelly. The ingredient is then placed on the tray and tray is then positioned it in the mouth. This ingredient mainly contains hydrogen peroxide or carbamide peroxide, hydrochloric acid, anesthetic ether etc. The solution is then placed in the oral cavity for 5mins at 1-min intervals. The tray is then removed and the solution is neutralised with baking soda solution and copious water irrigation.

For the treatment of most intrinsic toth satining tooth coloured porcelain laminate veneers have to be given.

1.   The patient should be motivated to discontinue the oral habits like tobacco chewing, smoking. The intake of various beverages like tea, coffee should be reduced.

2.   In case of any trauma to the tooth, the patient should immidiately report to a dentist to avoid any permanent damage to the tooth like pulp loss, root resorption, hypoplasia of the permanent tooth germ etc.

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