Internal whitening for teeth

mavrismenodontiHave you ever noticed while smiling, that one of your front teeth is darker that the rest of them?

Have you wondered why it happened and if there is a way to fix this?

Although there may be a lot of different reasons for  a tooth to be darker than the rest, the most common reason is internal discolouration or  pulp problems.

Discoloration usually happens after a trauma or root canal treatment and is the result of the degradation of the blood products inside the pulp chamber.

Enamel is affected by the degradations products and it changes its colour to brown, orange or dark gray. The problem may be noticed in both anterior or posterior teeth but the truth is our patients rarely care, unless the tooth is located at the front of their mouth.

Discoloration of a root canal treated tooth or a dead tooth is an esthetic problem that can easily be fixed with the technique of internal whitening.

Internal whitening is an economical dental treatment that does not affect the shape of the teeth, nor its position on the dental arch. Sometimes internal whitening may take place before an all ceramic prosthesis, in order to improve the colour of the abutment tooth that will allow the light to move easier through the abutment, improving the final esthetic result.

Before internal whitening the dentist has to make sure that your tooth has been treated endodontically with a good quality root canal treatment. This is usually done with the help of a periapical x ray.

Sometimes a tooth may loose its vitality due to a trauma and may suffer change of its colour without being ever endodontically treated. In a case like that root canal treatment has to be the first step of the treatment .

If the tooth is endodontically treated successfully, then we can proceed to the internal whitening immediately.

The treatment starts by removing the white filling on the top of the root canal treatment. Right after that we seal the root canal treatment with special materials that have as a purpose to isolate the root canal treatment from the whitening agent. As soon as this step is completed, we place the whitening factor in the space left on the crown of the tooth.

There are a lot of different types of whitening agents and the dentist chooses according to their preference. Some are light or heat activated while some, whiten the teeth over time. Sometimes the result is immediate while others the whitening agent may need replacement  on a follow up visit. 

If the root canal treatment is not good enough, internal bleaching should be avoided, unless a new root canal treatment is performed. The same goes for cases that have a minimal amount of healthy tooth structure or very large fillings.

Treatment usually results in teeth whiter in the middle and incisal part of the tooth. The lower third that is located closer to the gum line is harder to whiten because of the increased width of dentin. 

The picture presents a case from our practice where the central incisor had been whitened with the technique of internal whitening. 

internal whitening

Tooth discolouration may come back after a few years, but the scientific facts do not agree on how common this is. The percentages presented in the literature differ from 4% to 70%. We usually monitor these cases closely and when a relapse becomes important to our patient, we usually redo the procedure or make a crown or porcelain veneer. 

Internal whitening may have some side effects too. The most common side effect is the chemical burn that may happen due the material leackage during the whitening procedure. The most significant side effect is the external resorption of the root of the treated tooth. It is not clear though if the external resorption is due to the procedure or due to the trauma the tooth had suffered originally that had resulted to its root canal treatment in the first place. 

Do you have a dark anterior tooth? Have you ever had it whitened internally? What is your experience?

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