Tooth Discoloration and Its Treatment
Healthy teeth have a specific color for themselves, perhaps closest to white but not quite white. This very light yellow color of teeth is caused by the dentin and enamel. While the former causes the tooth's yellowness, the latter endows it with its whiteness. As people age, the enamel wears out thus gradually allowing the yellowness of the dentin to set in as the overall tooth color.
Generally, teeth may become discolored as a result of the following conditions:
1- Discolorations of the surface - These are due to germs, plaque, food colorings, and tobacco. These discolorations can be removed by regular brushing of the teeth, cleaning (that is, removal of germs from the teeth's surface) and polishing the teeth regularly by a dentist and/or dental hygienist, changing eating habits and limiting the amount of coffee and soft drink intake, and refraining from tobacco.
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2- Discolorations of the edges of fillings and inside tooth cracks - Teeth and composite fillings tend to crack from the inside over time as a result of aging, eating very solid edibles such as ice, certain nuts, etc. These cracks absorb the pigments inside the oral cavity and become discolored. Such cases will not be treated by mere cleaning; the discolored proportions should be restored by white materials.
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3- Discolorations caused by tetracycline - If children over the age of eight whose permanent teeth are growing use the antibiotic tetracycline or their mothers used this antibiotic when pregnant, their permanent teeth could be discolored and become yellow, gray, or brown. Bleaching and composite and/or porcelain veneers are suitable treatment plans for such cases.
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4- Discolorations due to tooth decay (caries) and faulty fillings - The mouth like many other human organs houses certain bacteria as a natural phenomenon. Excess of these bacteria and inadequate oral hygiene result in gradual decay of the teeth followed by discoloration. The best treatments for such discolorations is removing the decayed and discolored substance and faulty fillings and refilling with white materials.
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5- Discolorations caused by fluorosis - This discoloration impacts the surface layers of the enamel and makes the tooth turn opaque white to brown. The treatments are microabrasion and bleaching.
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6- Discolorations as a result of injury incurred to the tooth nerve - If a tooth receives a hard blow, the dental blood vessels and nerves at the end of the tooth may be torn thus blocking the blood circulation inside the tooth. In these cases, the tooth becomes gradually discolored and opaque. To deal with these conditions, root canal therapy is primarily required followed by bleaching. If the crown were damaged and even broken, composite fillings, porcelain laminate, and porcelain caps (in more serious conditions) could be used to restore the tooth.
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● Treatments for Tooth Discoloration
As stated above, tooth discoloration appears under various grounds and needs to be attended to differently, based on its cause of emergence. The most common methods of treatment are:
● Cleaning and Polishing
This is the easiest treatment process and the first step in all cosmetic procedures, particularly when the discoloration is caused by germs, plaques, and surface discoloration of the teeth.
● Bleaching or Whitening
Bleaching or whitening is essentially utilizing an oxygen-releasing substance which can whiten the teeth. This is the least damaging treatment procedure for tooth discoloration and consists of three categories depending on its functionality.
1-Home Bleaching
The dentist produces a plaster cast of the patient's two jaws and makes a night-guard out of it. Subsequently, the patient puts the bleaching materials into the night-guard and, depending on the concentration of the bleaching material, puts the night-guard in his/her mouth between 1-6 hours daily. The patient does this of course at home. The time required for the teeth on each jaw to become white is one to two weeks. This period could go up to six months in certain discolorations, especially those caused by tetracycline. The patient's teeth might become sensitive towards cold while using bleaching materials. It is advisable to decrease the hours of using the night-guard under these circumstances or even stop the process for one day. Using mouth washes and anti-sensitive toothpastes could help the patient recover. In any case, it is recommended that one inform his/her dentist should such sensitivity develop.
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2-Non-Vital Bleaching
In cases where a tooth becomes dark due to having received a blow, severe decay, or nerve treatment, the tooth must first undergo a complete nerve treatment, then all the dark substances should be cleaned from the tooth crown, and subsequently the bleaching materials should be injected inside the crown and restored with temporary material.. This material should remain inside the tooth crown for 1-2 weeks to remove the discoloration. Bleaching can remove black and gray discolorations better than orange ones. Sometimes there is need for several sessions of treatment. Once the crown is sufficiently white, the bleaching material is removed from the inside of the crown and filled with composite following one week of swab and.
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3-Office Bleaching
For those patients who are not in favor of home bleaching and seek quicker results, office beaching is the option. First, the teeth are cleaned and covered by bleaching materials. Then these materials are activated by light or heat thereby whitening the teeth. Under certain circumstances, nevertheless, a few sessions of treatment would be necessary for this procedure to take effect.
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4-Enamel Microabrasion
In cases where the discoloration has taken place in the surface layers of the enamel, bleaching alone may not do the trick; for such cases, microabrasion which is the slight removal of the enamel layer with attrition pastes is recommended
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● Composite Restorations (White Fillings)
Composites are white filling materials which are mainly polymerized and hardened by blue light (technically known as light cure). These materials can be used to restore or even cover the external layer of a discolored tooth. Composites are bonded to the teeth through dental adhesives technically called bonding.
Among the advantages of composites besides their beauty is the conservation of the tooth's healthy tissues throughout the filling process since there is no need to contour parts of the tissues as is the case with amalgam fillings. Yet, composite fillings require more precision and delicacy compared to amalgam. Hence, it would be best to refer to a dentist who is adept in such fillings.
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The durability of a composite filling varies from 3-8 years, provided they get polished once every few months and that the patient observes the dentist's recommendations well enough. Solid substances should not be bitten or broken by teeth which have been restored with composite since they could crack under such pressures. Having chocolate and coffee should be minimized especially in the first 24 hours after the treatment.
● Porcelain Laminate Veneers
Laminates are a thin porcelain or composite layer, which may be analogized to an artificial nail, covering the outside layer and edge of a tooth. These layers are bonded to the teeth with dental adhesives and composite cements and if well taken care of, can remain efficient between 5-12 years. Porcelain laminates are less influenced by color compared to composites and are more useful among those who smoke.
Porcelain laminates are produced by a dental technician in labs and then fixed permanently on the patient's tooth by the dentist. This treatment plan begins with opening a space so that the thin pieces of porcelain could be placed and bonded to the tooth. For this, 0.5-1 mm of the outer enamel of the tooth should primarily be grinded. Then an impression of the teeth is taken and sent to the lab for the dental technician to build up the required laminates on the dental cast. This procedure usually takes between 7 to 14 days to complete and once the laminates are ready and sent back to the office, the dentist would need one session to bond them to the teeth.
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Porcelain laminates are more expensive than composite fillings and if broken due to insufficient hygienic care or blow, are difficult to restore and it would be best to replace them. To preserve laminates, one must:
● Capping
In cases where the tooth's crown has been damaged seriously or that its discoloration has been such that it cannot be restored through aforementioned means, capping is the only remaining resort. Capping is the most detrimental method of treatment when it comes to preserving the health of the tooth's tissues. At least half to two-thirds of the healthy tissues of a tooth are grinded in this method to allow enough room for the crown to be mounted on the tooth.
Caps or crowns are categorized with respect to the kind of material used. The most common type of crowns is porcelain/metal in which the inside is made of metal covered by porcelain on the outside. Such crowns enjoy a high solidity and if produced with high quality, could achieve what both the dentist and the patient are looking for in terms of beauty. Different metals are used in crowns; those which contain gold are best when it comes to the marginal fitness of the crowns. Naturally, these are more expensive than crowns with cheaper metals.
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The second type of caps are metal-free crowns which contain no metal. These are more translucent and appear more natural in the mouth. Nonetheless, lacking metals, they have lower strength and are best used only for parts of the mouth which are readily seen.
As is the case with porcelain laminates, crowns are produced by dental technicians in a lab and thus require several sessions including impression taking of the teeth. Their duration varies from five to fifteen years depending on:
