8 months ago
There are many reasons for teeth to become discoloured and turn dark, but two main reasons usually cause this condition: root canal treatment and problems with the pulp of the tooth. A dental x-ray can help the dentist determine what’s really causing the problem.
You may notice a difference in colour between your natural, untreated teeth and your teeth that have undergone root canal treatment. Root canal teeth will not blend naturally with the rest of your teeth. They tend to look darker and duller than natural, untreated teeth. Why is this so? A tooth is made up of three layers: the enamel which is the outer layer that covers the tooth, the dentin which is the inner layer under the enamel, and the pulp which is the root of the tooth that contains the blood vessels and nerves.
When a tooth has decayed or fractured, bacteria will “eat” their way through the enamel and dentin layers until they reach the pulp. Once bacteria have reached the pulp, they break down the pulp tissue, exposing the nerves and blood vessels. This starts an infectious process within the pulp and eventually causes the blood vessels and nerves to die.
All the while, pressure from this infectious process causes you to feel pain from the infected tooth, and an abscess develops at the tip of the root. When the blood vessels and nerves die, the root turns dark brown in colour. Particles of this dead root permeate the dentin, and since the dentin is very porous, this causes the dentin to darken in colour as well. Since the enamel is translucent, the colour of the dentin shows through. This discolouration of the tooth stays the same even after root canal treatment. Unless this corrupted tissue is removed from the inside of the tooth, the infectious process would continue.
Teeth whitening may whiten your teeth and reduce discolouration. However, root canal treated teeth may not whiten as effectively and as quickly as your natural, untreated teeth. Root canal treated teeth would require more teeth whitening treatments than your normal teeth. They may need internal bleaching, or “walking” bleach, which is whitening the teeth from the inside.
Internal bleaching involves applying bleaching solution onto the nerve chamber of the tooth and sealing it with a temporary filling. This process is used because the dead roots have darkened the dentin, and the dentin is the part of the tooth that needs whitening for the enamel to look properly whitened form the outside.
Since teeth whitening and internal bleaching can be ineffective, your dentist may recommend placing dental crowns or veneers to correct the colour of your teeth. In fact in most cases, root canal teeth require a dental crown or veneer to be put in place to keep teeth strong and prevent it from cracking since its essentially dead. Whether you need a dental crown or veneer would depend on the amount of your tooth structure that still remains.
BDS (Hons.) MJDF RCS (Eng), MClinDent (FRP Lond) FICOI, MSc (Dental Implantology)
BDS (Lond) MJDF RCS (Eng)