Root canal treatment is done when infection reaches the pulp portion of the tooth. During root canal treatment, necrotic and infected portion of the tooth is removed and is then sealed with a filling material. If done with great precision and complete care, a root canal treated tooth can last lifelong. But in cases where root canal continues to harbor bacteria or irritants which keep the tissues surrounding the root of the teeth from being healthy (inflamed)even after the completion of the root canal treatment then the root canal treatment is taken to be a failure. Root canal failure signs and symptoms can occur month or years after root canal treatment. Pain occurs in root canal treated tooth in case of failure of root canal treatment.
These signs can be persistent from the time of root canal treatment, be transient varying week to months or even be dormant for years making the tooth appear completely asymptomatic during this dormant period. In cases where the tooth is completely asymptomatic, the signs of root canal failure which show as persistent inflammation surrounding the infected tooth, can be identified by the dentist through the medium of x-rays.
1. Shape of the Tooth’s Root Canals: Sometimes the tooth may have root canal branches which are difficult to detect. The canals which are curved and branch out often go undetected at times. These undetected branches might be missed in the root canal treatment leading to its failure.
2. Unexpected Number of Root Canals: There can be variation in number of canals which are present in the tooth. A tooth might have many small root canals also called as the accessory root canals which may be missed during the treatment. If a canal is missed during root canal treatment, then tooth can become infectious months or years after treatment and in such cases, root canal re-treatment is required.
3. Bacteria in root canal: Certain bacteria are very resistant in nature and no matter what it’s very hard to remove them therefore they easily escape the disinfection by root canal and infection persists.
4. Cracked root: By root canal therapy, roots of the tooth become bit brittle and can fracture on chewing which can further cause failure of root canal treatment. Dental crown after root canal treatment prevents fracture of tooth on chewing. Fracture of the root may occur during root canal treatment procedure and cause root canal treatment failure. It is difficult to diagnose these cracks and these cracks can lead to pain later on.
5. Breakage of file during root canal procedure: Accidental breakage of file during cleaning and shaping of canal during root canal treatment can cause infection in root canal treated tooth and failure of root canal treatment. If canals are sterilized and clean before breakage of file in tooth, then it doesn’t cause any symptom otherwise broken file in canal can lead to pain and infection later on. If file remains in canal before removing the necrotic pulp, then it has to be removed. File in unsterilized canals is to be removed before sealing the root canal treated tooth.
6. Defective or Incomplete Restoration: Defective or incomplete restoration at the end of root canal treatment fails to maintain a proper seal and this may lead to bacteria to penetrate back into the cleaned canal causing re-infection.
Inadequate filled canals and broken instrument in left lower incisor
7. Gum Disease: The treated teeth are not completely resistant to tooth decay or gum disease so the tooth might be lost if proper oral hygiene is not maintained. If patient doesn’t maintain good oral hygiene, then abscess can occur years after root canal treatment and dental crown.
8. Tooth Structure: The tooth structure which is damaged or broken as a result of treatment and which require restoration for stability which if not done can cause failure of root canal treatment.
The tooth filling even if accurately done at the time of treatment might break down with time due to some reason like high biting force which will again lead to seepage of bacteria into the canal and re-contaminate it
Success rate of root canal treatment is 95%. In about 5% of cases, complications may occur after root canal procedure which can lead to failure of root canal treatment.
To avoid further infections after getting root canal treatment and dental crown, it is important that patient maintains good oral hygiene and get regular dental check ups done.
In case of root canal failure, re-root canal treatment, Apicoectomy or tooth extraction may also be required to remove the infection from the tooth. Dentist will evaluate the condition of the tooth and will decide that whether tooth can be saved or not. If he thinks that prognosis of tooth after root canal treatment or Apicoectomy is not good, then he will pull the tooth out. If tooth extraction is required, then missing tooth can be replaced with dental implants, dental bridges or partial dentures. Dental implants are the best option for replacement of missing tooth.
Dental Implants after Tooth Extraction
Root canal retreatment can be done to save the tooth and tooth and remove the infection in root canal treated tooth. Procedure of root canal re-treatment is somewhat similar to root canal treatment and is mainly performed by an endodontist who is specialist in performing root canal procedure.
Apicoectomy that is surgical removal of root apex may be required to remove the infection from the tooth. To seal the root, small filling (retrofill) is used.
Bone Removal for Apicoectomy
Success rate of root canal treatment is not as high as root canal treatment done for the first time. Root canal treatment success rate is 50%-75%. If re-infection occurs after root canal re-treatment, then tooth extraction may also be required.
Free Dental Consultation