Possible reasons for the failure of a root canal treatment

A root canal treatment is done to save a tooth that has been damaged due to tooth decay and injury and to preserve it for a lifetime. In this procedure, the infected tooth pulp is removed, and the tooth is restored with the help of dental filling and dental crown. But sometimes the root canal treatment fails due to many reasons.

What are the signs and symptoms of the failure of the root canal treatment?

A successful root canal treatment helps the tooth to get rid of the symptoms of tooth decay, injury or other factors that led the patient to opt for the root canal treatment.

The main symptoms of the failure of the root canal treatment are:

• Pain: The tooth may start experiencing toothache just like it experienced pain before the procedure. This pain can be continuously present, or it may come and go.
• Tenderness and sensitivity: The tooth may feel tender and may become sensitive to food and drinks that are of hot or cold temperatures.
• Swelling: The gums around the tooth that has had a root canal treatment may experience swelling.
• Boil or infected outgrowth: An outgrowth of a boil can be seen around the gums of the treated teeth, and a foul smell may come out of it.

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Sometimes the tooth that has had a failed root canal treatment may not experience any pain or symptoms. But a routine X-ray done by the general dentist may show signs of damage to the tooth. This lack of symptoms is termed as tooth survival in endodontics.

What are the factors responsible for the failure of root canal treatment?

The following factors are responsible for the failure of a root canal treatment:

• Improper cleaning or removing of dental pulp: If the infected dental pulp is not removed and the dental hollow is not disinfected correctly then the root canal treatment may fail. It usually happens when the root canal has several branches or divisions. It makes the cleaning and decontamination of all the branches very difficult. Sometimes the dentist may altogether miss a branch or division leading to the failure of the treatment. It also happens when the tooth has an additional root canal. These additional canals are tiny and can be missed easily when the root canal treatment is done traditionally without the microscope.
• Improper sealing: When the tooth is not sealed correctly, internally, with dental filling during the procedure and with a dental crown during final restoration then it gives a chance to infections and contaminations to seep inside the tooth, leading to the failure of the treatment. Sometimes the root canal is sealed correctly during the treatment, but with time the seal may deteriorate leading to failure of the root canal treatment. In some cases, the final restoration or the crown is not durable enough to keep the contamination and infections out of the tooth. It is regarded as coronary leakage and is the leading cause of root canal failure.

• Technical difficulties: The dentist is sometimes faced with technical problems. Sometimes while doing the root canal the drills and files may damage the tooth structure and tooth roots. It leads to the failure of the whole process. In some rare cases, the root canal files break and get lost in the root canals and are not found back.
• The dentist may clean the dental pulp and disinfect the root canal, but sometimes the infected tissue can be attached to the root of the tooth. It can lead to failure of the root canal treatment as the tooth may require a removal of the root-tip or an apicoectomy.
• The expertise of the dentist: The success of the root canal treatment depends on the experience and knowledge of the dentist. A good general dentist can do an ordinary root canal treatment successfully but sometimes the root canal treatments are complex or complicated, and it can be handled well by an endodontist. Root canal treatment done by the endodontists have a higher success rate.

What can we do when a root canal treatment failure is suspected?

If we have all the symptoms of a failed root canal treatment, then Dr. Fay Mansouri, an Orange County Root Canal specialist, suggests seeing the doctor immediately, as a tooth which has been restored after an endodontic treatment can develop an infection or any other endodontic problem anytime. If the tooth is examined at the earliest, then the patient can be saved from flaring up of sudden intense pain and swelling.

References:

1. https://en.m.wikipedia.org/wiki/Endodontic_therapy
2. http://www.leongdental.com.sg/causes-of-root-canal-treatment-failure.html
3. http://irvineendodontist.com/