Internal Bleaching (Whitening a Single Discoloured Tooth)
Whitening a root-treated or trauma-discoloured tooth from the inside.
Why Does a Single Tooth Darken?
After an impact to the tooth, bleeding within the pulp tissue can cause blood components to spread into the dentinal tubules. Over time the breakdown products of these components colour the tooth tissue from within. In root-treated teeth, loss of tissue vitality and residues of certain materials can cause similar discolouration. The colour change may appear years after the impact.
Why Doesn't External Whitening Work?
In-office or home whitening addresses externally sourced discolouration on the enamel surface. Trauma-related discolouration, however, is located in the inner layer of the tooth, in the dentine. Surface applications therefore do not create a noticeable difference in a single dark tooth; the neighbouring teeth would also lighten, so the colour difference would not close.
How Is the Procedure Applied?
First the status of the tooth's root canal treatment is assessed radiographically; adequacy of the root filling is a precondition. An access is opened from the back surface of the tooth, the upper part of the root filling is removed to a certain level and a sealing barrier is placed at the canal entrance. The bleaching agent is then placed in the pulp chamber and temporarily sealed. The agent is renewed at intervals; once the desired shade is achieved, the tooth is closed with a definitive restoration.
How Many Sessions, and Is the Result Permanent?
The number of sessions varies according to the degree of discolouration and the tissue's response to the agent; several applications may be needed. The degree of lightening achieved and its permanence vary between individuals. Partial colour relapse may be seen over time and the procedure may need to be repeated. Expectations are therefore discussed together beforehand.
Alternative and Complementary Approaches
If the discolouration is accompanied by loss of structure, fracture or marked deformity, whitening alone may not be sufficient; options such as composite restoration or a laminate veneer may be considered. Which approach is suitable is determined by the current condition of the tooth.
Frequently Asked Questions
How is internal bleaching carried out?
In a tooth whose root canal treatment is complete, a protective barrier is placed over the root filling and the bleaching agent is placed inside the crown of the tooth. It is sealed with a temporary filling and the agent is left in place for a period. Once the shade reaches the desired level, the space is filled with a permanent restoration. Because the procedure works from inside rather than outside the tooth, it is considered for internally originating discolouration where external whitening is insufficient.
How many appointments does it take?
The number of appointments varies with the depth of the discolouration and how the tooth responds to the agent. The agent is generally left in place for a few days, the shade is assessed at a review appointment and renewed if needed; this cycle may be repeated more than once. A definite duration cannot be stated in advance, as the rate of lightening differs between individuals.
Will the shade darken again?
Some return of colour over time is possible; this is the expected course and does not mean the procedure has failed. How quickly it returns depends on the original cause of the discolouration, the restorations in the tooth and oral hygiene. The procedure can be repeated where indicated. A permanent shade cannot be committed to.
Are there risks with internal bleaching?
The principal risk reported in the literature is external root resorption beginning at the neck of the tooth. Placing a protective barrier over the root filling and selecting an appropriate agent are important in reducing this risk. For this reason the state of the root canal treatment is assessed radiologically beforehand and the tooth is reviewed at intervals afterwards.
The information on this page is for general information purposes and does not replace a clinical examination. The suitability, duration and alternatives of treatment can only be determined by your dentist after clinical and, where required, radiological evaluation.
This treatment is carried out at the clinic in Yeşilbahçe, Muratpaşa, Antalya. Location and directions.