One of the greatest assets a person can have is a smile that shows beautiful natural teeth. People are very sensitive about unattractive teeth. Discolored, malformed, crooked or missing teeth lead to a conscious effort to avoid smiling. Restoration of smile is one of the most appreciated and gratifying service a dentist can render. A pearly white smile is the dream of every individual.

Causes of Discoloration

Discoloration can be caused by extrinsic and intrinsic causes.

Causes of Tooth Dicoloration 

Intrinsic Discoloration

These are caused by deeper internal stains or enamel defects. Teeth with vital or non vital pulps and root canal treated teeth can be affected.

Vital Teeth may be discolored at the time of formation of crowns and the abnormal conditions involve several teeth. Causative factors include hereditary disorders, medications, excess fluoride, high fevers associated with childhood illness, and other traumas.

Tetracycline preparations can cause the most distracting type of discolorations. Different type of tetracycline induces different types of discoloration. Dark blue gray tetracycline stained teeth are more difficult to treat than teeth with mild yellow orange discolorations. The staining effects are a result of chelation of the tetracycline molecule with calcium ions in hydroxyapatite crystals primarily in dentine. Tetracycline is incorporated in to the dentine and enamel. The chelated molecule arrives at the mineralizing predentine – dentine junction via the terminal capillaries of the dental pulp. The brown discoloration is due to photo oxidation which occurs on exposure of tooth to light. All degrees of stains become more intense on exposure to artificial light and sunlight.

Minocycline: This is used to treat acne and various infections. It causes discoloration by chelating with iron to form insoluble complexes. Resultant staining is milder than tetracycline and may be amenable to bleaching and lightening.

Excess Fluoride: staining due to excess fluoride in water is usually generalized and the condition is called fluorosis. It occurs within the superficial enamel and appears as white or brown patches of irregular shape. The acquisition of stain is however post eruptive! As the teeth are porous they gradually absorb the colored chemicals present in the oral cavity. Staining due to fluorosis manifests in three ways: as simple fluorosis. Opaque fluorosis, and fluorosis with pitting.

Illness and Trauma During Tooth Formation: Effects of illness, trauma, medication like porphyria, infant jaundice, vitamin deficiency, phenylketonuria, hematological disorders etc create stains which cannot be treated by bleaching. In some disorders like erythroblastosis fetalis, porphyria, phenylketonuria, sickle cell anemia, the coagulation system is affected which leads to the presence of blood within the dentinal tubules hence the discoloration.

Ageing: As people grow older, the tooth enamel becomes thinner because of wear and allows the underlying dentine to become more apparent. Also, there is continued deposition of secondary dentine in older individuals resulting in greater dentin thickness. This deposition results in yellowing effect. Additionally permeability of teeth allows infusion of organic pigments from chromogenic foods, drinks, and tobacco products that produce a yellow color.

Non Vital Teeth can also become discolored intrinsically. The pulp may become infected or degenerate as a result of trauma, deep caries, or irritation from restorative procedures. The degenerative products from the pulp tissue stain the dentin and are readily apparent because of the translucency of enamel.

Causes of Tooth Discoloration and types of dental stains

Extrinsic Discoloration

Stains on the external surfaces of teeth are common and may be due to many causes. These stains may be related to remnants of nasmyth’s membrane, poor oral hygiene, existing restorations, gingival bleeding, plaque accumulation, eating habits, or the presence of chromogenic bacteria.

Plaque: Pellicle and calculus on the surface of tooth can give it a yellow appearance.
Tobacco: Products of tobacco dissolve in saliva and lower its ph, facilitating penetration of pits and fissures. This gives the tooth a brown/ black appearance.
Food and Beverages: Tea, coffee, red wine, berries, cola, curry results in surface and absorptive staining.
Poor Oral Hygiene: It may result in green, brown black and orange staining which is produced by chromogenic bacteria.
Chlorhexidine: It is a mouth wash and causes black and brown staining. Staining is enhanced in presence of tea and coffee. It may be related to precipitation of chromogenic dietary factors on teeth and mucous membranes. It is probable that the associated cationic group producing the bactericidal effect can attach the dietary factors such as Gallic acid derivatives found in foods and beverages such as tea and coffee and tannins to the molecule and hence to the tooth.

                                                              Causes of Teeth Coloration due to dental stains

Staining Due To Dental Restorations

  1. Eugenol used in root canal treatment may cause an orange yellow discoloration.
  2. Endodontic material and pulpal remnants may cause a grey or purple stain.
  3. Silver amalgam causes a gray brown discoloration on teeth.
  4. Leaking composite restoration can cause the tooth to appear more yellow.

Various Treatment Options Available for Teeth Whitening

There are many treatment options available for teeth whitening but before commencing with it, it is essential to question the patient to determine the etiology of discoloration.

  1. Correction of intrinsic discoloration caused by restorations entails replacement of faulty restoration
  2. Correction of discoloration by caries requires appropriate restoration.

For other types of stains teeth whitening bleaching methods should be used.

Most bleaching techniques use some form of derivative of hydrogen peroxide in different concentrations. Mechanism of action of hydrogen peroxide in teeth whitening procedures is considered to be oxidation of organic pigments.

Bleaching has an overall life span of 1-3 yrs.

Tooth whitening products and their composition

Treatment Procedures Available for Teeth Whitening

The lightening of the tooth color through the application of a chemical agent to oxidize the organic pigmentation is called as bleaching. Most bleaching techniques use some form or derivative of hydrogen peroxide in different concentrations and application techniques.

Non Vital Bleaching Procedure

When to Go For Non Vital Bleaching Procedure?

  1. To lighten teeth those have undergone root canal treatment.
  2. In case bleeding from root canals has caused discoloration.
  3. In case degraded pulpal remnants has caused discoloration.
  4. Due to staining from dental restorations and cements.

Most posterior teeth that have undergone rct require full coverage restorations that encompass the tooth to prevent fractures. But anterior teeth are mostly intact and may be restored with composite rather the full crown restorations. So most commonly it’s the anterior teeth which requires whitening procedure in case of non vital teeth.

In Office or Thermo Photo Bleaching

Thermocatalytic Technique - This consists of placement of 35% hydrogen peroxide into debrided chamber and acceleration of oxidative process by placement of heating instrument into the pulp chamber.

In this method a 2 mm layer of protective white cement barrier like zinc phosphate gic intermediate restorative material is applied on the endodontic obturator. Then a small amount of 30-35% hydrogen peroxide is placed on a small cotton pellet and is placed on pulp chamber. A bleaching gel may be used as well. Then heat is applied with a heating device or a light with temperature between 50-60c. Tooth is allowed to cool for at least 5 min and then washed with warm water.

Patient is recalled after 2 weeks for evaluation.

Walking Bleach

When to opt for walking bleach?

  1. Discoloration of pulp chamber
  2. Dentin discoloration
  3. Discoloration not amenable to extra coronal bleaching


  1. Less chair time
  2. Safer
  3. More comfortable

In this technique either superoxol i.e. 30% hydrogen peroxide by volume or a mixture of sodium perborate and superoxol is used.

Procedure of Walking Bleach

In this method, after opening the canal gutta percha is removed up to 1-2 mm apical of clinical crown and endodontic access is enlarged to ensure complete debridement of pulp chamber. Discolored dentine is exposed by trimming the excess material.

Sodium Perborate is used. One drop of saline or sterile anesthetic solution is blended with sodium perborate to form a cream paste. With a spoon excavator material is filled in pulp chamber to within 2 mm of cavosurface margin. Temporary sealing material is placed. Sodium perborate should be changed weekly. On successful bleaching chamber is rinsed and filled with a paste of calcium hydroxide powder.

In case discoloration appears again external bleaching should be done.

Vital Bleaching Procedure

When to go for vital bleaching?

  1. Intrinsically discolored teeth from ageing, trauma, drug ingestion,
  2. Alternate treatment for a failed non vital walking bleach procedure.
  3. Single teeth darkened from trauma
  4. Brown fluorosis stain.

In Office Vital Bleaching Treatment

Though the process uses very caustic chemicals it is totally under the control of the dentist.Itis expensive and has an predictable outcome. It is also called as chair side bleach or power bleach or laser bleach.

Materials used in power bleach are.

  1. 35% hydrogen peroxide liquid or gel called as power gel or laser bleaching gel.
  2. 35% carbamide peroxide
  3. Dual activating bleaching system.

How Does In Office Vital Bleaching Treatment Work?

  1. Works by lightening the enamel to give a whitened appearance.
  2. There are two theories regarding its mechanism of action.
  3. First one says that large colored organic molecules responsible for stains are reduced to smaller less noticeable molecules by oxidation.
  4. Second theory says that peroxide penetrate in enamel and dentine and oxidizes tooth discoloration.

Procedure of In Office Bleaching

  1. Teeth are cleaned by a pumice prophylaxis paste.
  2. Bleaching material is applied.
  3. Light is applied close to tooth. Plasma arc light emits 3 – 5 bursts of light. It is continued for a period of three , 3 min intervals and bleach is removed after that via high volume aspirator. Teeth are then washed and bleach is reapplied for a further time of 1 min. process is repeated for 45 min – 1 hr.
  4. Process can be repeated after 6 weeks increment until the desired shade is obtained.

Dentist Prescribed Home Bleaching Technique

This is also called as night guard technique. The main features of this technique are:

  1. Less labor intensive.
  2. Uses lower concentration of carbamide peroxide. 10-15% carbamide peroxide is used which degrades into 3% HYDROGEN PEROXIDE AND 7 % UREA.

When to Go For Home Bleaching

This is also called as night guard technique. The main features of this technique.

  1. Mild generalized staining.
  2. With age yellow discoloration.
  3. Mild tetracycline staining.
  4. Mild fluorosis.
  5. Superficial staining.
  6. Tobacco staining.

Procedure for Home Bleaching  

Alginate impression is made and good details should be achieved. It is poured immediately and bleaching trays are made.

Bleaching material should be selected. Various concentrations are available... 5%, 10%, 15%, 20%, upto 35%.check for tray fitting. Patient is provided with all the essential material comprising of bleaching paste cotton buds cotton rolls in a kit. Bleaching schedule should be informed to the patient.

Laser Bleaching Technique:

This is a New Revolution in Fast Bleaching Procedures. Laser assisted bleaching techniques have been introduced as an attempt to accelerate the bleaching process. However this is a technique for which there is least amount of clinical research. Long term affects using laser assisted bleaching are not yet established.

Types of Lasers:

There are four types of lasers being used in dentistry. Carbon dioxide, neodymium:yttrium-aluminium-garnet(nd:yag) and erbium-chromium-ytrrium-scandium-gallium-garnet(ercr:ysgg) lasers.

Lasers are used to enhance the activation of the bleaching material. The lasers provide energy for the hydrogen peroxide to break down into water and oxygen and to release the oxygen into the stained tooth. They catalyze the oxidation reaction. The free radicals of oxygen liberated in this process break apart the double valancy bond into simpler more stable, less pigmented chains.

 It may at as a jump start for difficult cases and helping to remove difficult stains caused by tetracycline and fluorosis.    

Teeth Whitening FAQs

What causes dulling and discoloration of teeth?

Discolorations can be caused by staining, aging, or chemical damage to teeth. Tooth dullness or staining is an indication that whitening should be considered. Smokers and those who drink coffee and/or tea on a regular basis accelerate the discoloration and require cleaning.

Is teeth whitening safe?

It is a very safe procedure with no pain. It involves the use of hydrogen peroxide in mild concentrations. It requires less time and sometimes may be completed within an hour.

What are the side effects of teeth whitening?

The side effects of teeth whitening are very minimal and vary by individual. If you have sensitive teeth or gums, defective restorations, or severely receding gums, you should consult with your dentist before you begin any teeth whitening procedure. Many patients who have sensitive teeth can still benefit from treatment as long as they use a milder version of the peroxide whitening formula. Patients who are allergic to peroxide should not consider traditional teeth whitening methods. Severe side effects may include chemical burns external root resorption and damage to the existing restorations.

How long does the bleaching last?

Normally the new white color lasts quite well. However the effect is dependent on what has caused the teeth to discolor in first place. If you drink lots of tea coffee cola red wine the effect may darken slightly.

How to do post bleaching care?

Patients should continue there regular maintenance visits which includes periodic oral health evaluation and visits to dental hygienist. Additional rebleaching or top up bleaching is easy and can be done every 2- 3 yrs. Foods and drinks which cause severe staining should be avoided.

Leave Comment


  • MAdi Adam

    MAdi Adam 16 - September - 2011, at 16:29 PM

  • thank you so much for your kind & help..

  • dr ritz

    dr ritz 16 - September - 2011, at 02:40 AM

  • Madi Adam, Firstly you need to know whether there are intrinsic stains or extrinsic stains present on the teeth. For the treatment of extrinsic stains, you can go for dental cleaning followed by professional teeth whitening which is the fastest and safest way of teeth whitening. Bleaching gel is used in this which has hydrogen peroxide. If there are intrinsic stains present, then you can go for veneers or lumineers or crowns for it. You can take help of your friends or can browse on net to know about good dentists at your place. It is important that you brush and floss regularly to have healthy teeth.

  • MAdi Adam

    MAdi Adam 16 - September - 2011, at 00:20 AM

  • would you kindly please show us what is the ideal bleaching or whitening that we could go for it? & how to know that whatever our dentist do is right? thank you..

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