Root Canal Treatment Part II

Top 10 Common Reasons For Why Root Canal Treatment Fail

Reason #8: Filling the root canal way too short or going way past the end of the root

Root Canal Treatment - Fillings

If your dentist miscalculates the length (depth) of your canal, a variety of problems may develop. If your dentist cleans and measures the canals short of the apex, then the filling compound he uses to fill the canal will not touch the root bottom.

This means that infected tissues will remain in the canal, and this will likely stimulate the development of an abscess.

If your dentist overestimates the length of the canal, this can also lead to failure. By misjudging the root length, a terrible error of too much enlargement of the end of the root can occur. “Blown open”, the end of the root will lose its sealing potential and the root canal filling materials will overfill the end of the root, causing a poor seal of the canal system.

Reason #7: Leakage of bacteria into the root canal system from the top of the restoration

Root Canal Treatment - Bacteria

The entire process is aimed at removing bacteria in the roots. But if you experience a breakdown or degradation of the tooth-sealing filling, which could be permanent or temporary, your root canal can leak bacteria back into the system and cause a failure. This is why a permanent seal is necessary following any root canal treatment. A crown does this by covering and sealing out anything getting back into the tooth while adding protection from fracture which is commonly seen with root canal teeth.

Timing for a final restoration is important if you want to avoid leakage. If your restoration work is delayed following your procedure, it could influence a bacterial re-infection in your canal. Even worse, if the rubber filling material is exposed to saliva for three days, research shows bacteria will permeating into the canal system. Dentists should retreat your root canal once this occurs.

Reason #6: Insufficient filling of the root canal (known as obturation or canal filling)

Root Canal Treatment - Obturation

Once the canal is cleaned, it has to be sealed inside out. This root canal filling is the white material you will see on an x-ray. Root canals are set and sealed in place with a cement compound and with Gutta-Percha which is a rubber material made from a tree. Since rubber is used to fill up the empty space, it makes sense that it should be dense and tightly packed to prevent bacteria from re-breeding or getting back into your tooth. A possible source of failure is not making the “obturation” dense enough. Nowadays, at Westcoast we use a variety of 3D methods to fill completely the canal including Thermafil, vertical warm condensation and obtura back filling. All of this ensures your root canal doesn’t allow bacteria a chance to repopulate your tooth again.

Reason #5: Missing or unable to access a hidden root canal

Hidden Root Canal - 7 Canals

The presence of an obscured or unexpected extra canal that is undetected is another cause of failure. In some odd cases one of your lower incisors which normally has just a single canal, may have a second one to the posterior and that wayward canal system can have up to four branches behind it. If the extra canals are not detected, it may eventually lead to an infection in your tooth which stimulates the growth of an abscess, culminating in a failed root canal.

This is one of the most difficult tasks when root treating a tooth. Finding all the canals and ensuring each is cleaned and shaped adequately to the apex of the tooth is a goal in canal therapy.


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