Tooth bleaching or tooth whitening is a wide spread procedure among dentists that perform it as part of other cosmetic dentistry treatments. There are various procedures for whitening the surface of teeth, from in-office whitening to over the counter teeth bleaching gels or strips. However, in devitalized teeth, the change in color appears due to internal stains caused by structural changes of the tooth, by blood and other fluids which may have penetrated the tooth. Therefore, whitening a devitalized tooth is a different procedure which focuses on the interior part of the tooth.
Internal Tooth Bleaching Defined
Internal bleaching is the procedure used by dentists to whiten teeth which have been under an endodontic treatment or a root canal treatment. The treatment consists in treating the pulp or removing the infection and the nerve tissue from the pulp of the tooth. This procedure can cause changes in the tooth’s color, which may also be due to bleeding during the procedure or the insertion of other colored fluids that affect the toot.
The internal tooth bleaching consists of the insertion of an oxidizing chemical substance into the tooth’s pulp, using a small drilled incision into the pulp chamber. Before the actual bleaching agent is inserted, the area is cleaned and the canals are sealed. If the first amount inserted did not succeed in whitening the tooth properly, the bleaching gel can be replaced in a few days.
The internal bleaching gel has the same effect as the external bleaching products, but it acts from the inside of the tooth. The procedure can be performed as a self standing procedure or correlated with external whitening procedures. However, you have to ask your dentist whether it is recommended to combine the two, because the condition of the tooth does not always allow it, or it might not be necessary.
Techniques for Internal Tooth Bleaching
Internal tooth bleaching can be done via two techniques:
- The chairside technique, which involves the use of 30%-35% Superoxyl combined with hydrogen peroxide. The technique is sometimes used with heat and is very efficient. But, given the concentration of the oxidizing substance, it can cause burns. There is also a high chance of cervical absorption.
- The walking bleach technique, which involves the usage of sodium perborate and water. This procedure is safer that the other one and can be used if the former does not work or if you want to avoid cervical absorption.
Indications for Internal Tooth Bleaching
There are cases when internal bleaching is not performed. In case the stains can be removed through external whitening, this procedure is preferred. The tooth has got to be strong and healthy enough so that the drilling and the insertion of bleaching chemical substances do not damage it. This is why sometimes additional treatments are performed before the bleaching.
Internal bleaching is recommended when the color changes originate in the pulp and if the stains cannot be cleaned externally. If there are cavities, composites which changed color, serious loss of dentine, enamel surface stains or enamel deformation, the internal tooth bleaching is not recommended.