You’ve had a root canal. The procedure was successful — the pain is gone, the tooth is saved. But over the following months, you notice something: the tooth is getting darker. Grey. Sometimes nearly black. The adjacent teeth are fine. The discoloured tooth is conspicuous, particularly if it’s a front tooth.
This is a well-understood, clinically common, and crucially — entirely treatable consequence of root canal treatment. It is called non-vital tooth discolouration, and the treatment for it is internal bleaching (also called non-vital bleaching or walking bleach).
Novo Care performs internal bleaching in Addis Ababa as a specialist procedure for patients with internally darkened teeth whether from root canal treatment, previous trauma, or other causes of pulp death.
Why teeth darken after root canal treatment
When a tooth undergoes root canal treatment, the dental pulp the soft tissue that contains the blood supply and nerve is removed and the space is sealed with a filling material. The tooth is effectively no longer “living” in the biological sense.
The darkening that follows happens through two mechanisms. First, if blood has leaked into the dentinal tubules (the microscopic channels within the tooth structure) during the pulp’s deterioration or during treatment, the breakdown products of haemoglobin — particularly iron sulphide compounds — stain the dentine permanently from within. Second, some traditional root canal filling materials (particularly older eugenol-based sealers) can leach pigments into the surrounding dentine over time.
The result is discolouration that is intrinsic within the tooth structure itself and cannot be removed by standard external whitening treatments. Applying bleaching gel to the outside of an internally darkened tooth produces no meaningful improvement, because the gel cannot penetrate to where the staining is.
What internal bleaching involves
Internal bleaching treats the discolouration from the inside of the tooth — exactly where it originates.
The procedure, step by step:
First, the existing root canal filling is accessed through the back of the tooth (in the case of a front tooth) or the top of the crown (for a back tooth). A protective barrier material is placed over the root canal filling to prevent any bleaching agent from entering the root.
The bleaching agent — typically sodium perborate in combination with hydrogen peroxide, or a carbamide peroxide gel — is placed inside the access cavity, which is then sealed with a temporary filling. The bleaching agent works on the dentine from within, breaking down the iron sulphide pigments and lightening the tooth.
The sealed tooth is left for approximately one week, during which the bleaching agent works progressively. The patient returns at intervals of one to two weeks; the bleaching agent is refreshed and the progress assessed clinically. Most cases require two to four applications over three to six weeks to achieve the desired result.
When the target shade is reached, the access cavity is permanently sealed with tooth-coloured composite resin.
What results to expect
Internal bleaching consistently produces significant lightening of non-vitally discoloured teeth. The degree of improvement depends on the cause and severity of the discolouration: early, recently discoloured teeth typically bleach more readily than long-standing, severe discolouration.
In most cases, the bleached tooth can be matched closely to the shade of the adjacent natural teeth. Complete elimination of all discolouration is not always achievable in the most severe cases, but meaningful, cosmetically significant improvement is consistently achieved.
The result of internal bleaching is not permanent in the same way that a veneer is permanent — some degree of recolouration can occur over years, and patients should be advised that a repeat bleaching course may be required after 5 to 10 years.
When internal bleaching is not sufficient
For teeth where internal bleaching achieves inadequate improvement, or where the tooth structure has been significantly compromised by the root canal treatment and subsequent history, the next treatment options are:
A composite veneer or porcelain veneer, which restores the external appearance of the tooth regardless of the internal colour. A veneer is placed on the front surface only and does not affect the root canal treatment.
A full porcelain crown, which covers the entire tooth and provides complete colour control. A crown is typically indicated when the tooth has lost substantial structure and requires full coverage restoration in addition to cosmetic improvement.
Novo Care’s treatment planning process always begins with the most conservative option that will achieve the desired result. Internal bleaching, where appropriate, is preferable to a veneer or crown because it preserves natural tooth structure.
Novo Care performs internal tooth bleaching in Addis Ababa. If your tooth has darkened after a root canal, contact us for a specialist assessment.