Sodium hypochlorite accident
A sodium hypochlorite incident is an immediate reaction of severe pain, followed by edema, haematoma and ecchymosis, as a consequence of the solution escaping the confines of the tooth and entering the periapical space.This may be caused iatrogenically by binding or excessive pressure on the irrigant syringe or it may occur if the tooth has an unusually large apical foramen. It is usually self-resolving and may take two to five weeks to fully resolve.
Tooth discoloration is common following root canal treatment; however, the exact causes for this are not completely understood. Failure to completely clean out the necrotic soft tissue of the pulp system may cause staining, and certain root canal materials (e.g. gutta percha and root canal sealer cements) can also cause staining.Another possible factor is that the lack of pulp pressure in dentinal tubules once the pulp is removed leads to incorporation of dietary stains in dentin.
Poor-quality root filling
Another common complication of root canal therapy is when the entire length of the root canal is not completely cleaned out and filled (obturated) with root canal filling material (usually gutta percha). The X-ray in the right margin shows two adjacent teeth that had received bad root canal therapy. The root canal filling material (3, 4 and 10) does not extend to the end of the tooth roots (5, 6 and 11). The dark circles at the bottom of the tooth roots (7 and 8) indicated infection in the surrounding bone. Recommended treatment is either to redo the root canal therapy if possible, or extract the tooth and place dental implants
Root canal treatment may fail for many reasons: one common reason for failure is inadequate chemomechanical debridement of the root canal. This may be due to poor endodontic access, missed anatomy or inadequate shaping of the canal, specifically in the apical third of the root canal, also due to the difficulty of reaching the accessory canals which are minute canals that take long in from the pulp to the periodontium in a random direction. They are mostly found in the apical third of the root.
Exposure of the obturation material to the oral environment may mean the gutta-percha is contaminated with oral bacteria. If complex and expensive restorative dentistry is contemplated then ideally the contaminated gutta percha would be replaced in a retreatment procedure to reduce the risk of failure.