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.
Discoloration can be caused by extrinsic and intrinsic causes.
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.
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.
Staining Due To Dental Restorations
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.
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.
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.
When to Go For Non Vital Bleaching Procedure?
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.
When to opt for walking bleach?
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.
When to go for vital bleaching?
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.
How Does In Office Vital Bleaching Treatment Work?
This is also called as night guard technique. The main features of this technique are:
When to Go For Home Bleaching
This is also called as night guard technique. The main features of this technique.
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.
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.
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