Internal Tooth Whitening: Restoring Discoloured Teeth After Root Canals

One of the main aesthetic challenges we face as dentists, is a dark discoloured front tooth. This usually results from after a root canal treatment which may be needed for a variety of reasons but is usually from trauma. The reasons for the discolouration do vary. This could be from remnants of the pulp tissue being left within the root canal system and then decomposing within the tooth permeating into the dentine. There can also be rupture of the blood vessels within the pulp allowing blood products to seep into the dentinal tubules and discolour the tooth as this degrades. Another common reason is not so well known. Studies have shown that another factor could be the result of not removing all of the root canal sealant material once the tooth has been treated. van der Burgt TP, Mullaney TP, Plasschaert AJ. Tooth discoloration induced by endodontic sealers. Oral Surg Oral Med Oral Pathol. 1986;61:84–9. [PubMed] [Google Scholar] [Ref list]
The chromophores resulting from the disintegration of root canal sealer remnants penetrate through the dentinal tubules into the coronal tooth structure gradually causing progressive discoloration. The key factor is that most root treated teeth do appear darker than non root treated teeth and when this is on a front tooth, it is a major aesthetic issue.

The key factor for internal tooth whitening is that the root canal treatment is of a high quality and the filling material has been sealed properly in the coronal aspect ( top part) of the tooth. Our dedicated process involves careful placement of 6% hydrogen peroxide, usually Daywhite ZOOM by Phillips directly into the opening from the back of the tooth. In most cases, we will open the area so that the exact size of the syringe from the whitening tube can be directed into the area so that there is zero guess work. A slow insertion and pull back technique is needed so that the whitening gel just exudes from the tooth. Then a specially made tooth whitening tray or orthodontic retainer is placed over the top. This should be left for 3-4 hours and then replenished with some new gel. Ideally, this takes place over 2-3 days so we generally advise starting on a Friday and then coming back to us on Monday or Tuesday. We will then fill the back of the tooth with a white composite material.

This has worked incredibly well over many years at the practice as our case below will highlight. Once the internal tooth whitening has been completed, conventional external whitening should be undertaken for a period of 1-2 weeks for the best results.

Our case of the month involves internal whitening a central tooth which was discoloured for many years following a root canal treatment. The treatment was completed within a few days using our very own technique as described above.

If you have a similar problem and would like to effectively resolve the issue, contact us at our dental practice in Fulham and we will arrange your first appointment towards a whiter and naturally aesthetic smile.