Non-vital (Internal) Bleaching

February 24, 2011 by genioadmin

Topics

Internal Bleaching
‘Walking bleach’ technique
Complication
Limitation

Internal bleaching procedures are performed on devitalized (dead) teeth that have undergone root canal therapy (or RCT) but are discolored due to internal staining of the tooth structure by blood and other fluids that leached in. Unlike external bleaching, which brightens teeth from the outside in, internal bleaching brightens teeth from the inside out.

Bleaching the tooth internally involves drilling a hole to the pulp chamber, cleaning, sealing, and filling the root canal with a rubber-like substance, and placing a peroxide gel into the pulp chamber so the gel can work directly inside the tooth on the dentin layer.In this variation of whitening the peroxide is sealed within the tooth over a period of some days and replaced as needed, the so called “walking bleach” technique.

‘Walking bleach’ technique

Before treatment a radiograph would be made to check the quality of the root filling.
The quality and colour (shade) of any restoration present are assessed.
Tooth colour was evaluated and clinical photographs were taken at the beginning of and throughout the procedure.
Rubber dam should applied to isolate the treated tooth, to prevent reinfection of the root canal, and to protect the adjacent structures from the bleaching agent.
The restorative and the obutarating material was removed until below gum margin
A layer of cement was applied on top of the obturating material.
Bleaching agent: sodium perborate mixed with 30% hydrogen peroxide into paste form was be loaded into the pulp chamber of the tooth.
Finally, a temporary restoration was used to cover the cavity
The patient was rescheduled approximately 1 month later and the procedure was repeated 2 to three times.

Internal-bleaching21 — Walking bleach, A, Internal staining of dentin caused by remnants of obturating materials (OM) in the chamber as well as by materials and tissue debris in pulp horns (PH). B, Coronal restoration is removed completely. C, A protective cement base (B) is placed over the gutta-pecha. A paste (P) of sodium perborate and hydrogen peroxide is placed. D, A thick mix of temporay cement (Z) seals access. E, At a subsequent appointment when the desired shade reached, a permanent cement is placed (TS) at the pulp chamber and composite resin (C) to seal of the access

Complication

External resorption – Internal bleaching occasionally induces external cervical root resorption. Chemicals combine with heat are likely cause necrosis of the cementum, inflammation of the periodontal ligament, and root resorption.
Crown (Coronal) fracture – Increased brittleness of the crown part of the tooth, particularly when heat is applied resulting in the tooth is more susceptible to fracture.
Chemical burn – 30% hydrogen peroxide is caustic and will cause chemical burns and sloughing of gingiva. Therefore, rubber dam is needed to protect the gum from chemical burn.

Limitation

Even though internal bleaching can produce satisfactory result in most cases, no all will achieve the desirable result. Therefore, other options such as full porcelain crown, porcelain veneer will be the alternative to whiten non-vital tooth!!