A root canal is a dental treatment that saves a tooth whose inner soft tissue, the pulp, has become infected or badly inflamed. The dentist numbs the tooth, removes the damaged pulp, cleans and disinfects the canals inside the root, and seals them. The tooth is then restored, often with a crown, so you keep your own tooth instead of having it removed.
What does root canal mean?
Strictly, the root canal is a part of the tooth: the narrow channel running down the inside of each root. Under the hard enamel and the dentine beneath it is the pulp, a soft tissue of nerves and blood vessels that fills the pulp chamber and the root canals. Front teeth usually have one canal; back teeth often have three or four.
In everyday speech, "a root canal" means root canal treatment (RCT): the procedure that cleans out and seals those channels when the pulp is damaged.
Why would a tooth need a root canal?
The pulp can be damaged when bacteria reach it or when the tooth is injured. Common causes are:
- deep decay that has reached the pulp
- a crack or fracture in the tooth
- a large or leaking old filling, or repeated work on the same tooth
- a knock or injury, even one that left no visible damage at the time
Once the pulp is infected it cannot heal on its own. Left untreated, the infection can spread into the bone at the root tip and form an abscess.
Signs you may need a root canal
- toothache that lingers, throbs or wakes you at night
- pain when you bite or chew on one tooth
- sensitivity to hot or cold that lasts after the food or drink has gone
- swelling of the gum or face near a tooth
- a small pimple or boil on the gum that may leak a bad taste
- a tooth that has turned darker, often after an injury
Some infected teeth cause no symptoms at all and are found on a routine X-ray. Equally, not every toothache means a root canal: sensitive teeth, gum problems and sinus pressure can feel similar. Only an examination and X-ray can tell, so see a dentist rather than waiting for the pain to settle. Seek care urgently if you have facial swelling that is spreading, a fever, or any difficulty swallowing or breathing.
The root canal procedure, step by step
- Diagnosis. The dentist examines the tooth, may run simple tests for sensitivity, and takes an X-ray to see the roots and any infection. In complicated cases a 3D scan may help.
- Local anaesthesia. The tooth and surrounding area are numbed.
- Isolation. A thin rubber sheet, called a dental dam, is often placed around the tooth to keep it clean and dry and to stop anything falling into your mouth.
- Access. A small opening is made in the top of the tooth to reach the pulp chamber.
- Cleaning and shaping. The damaged pulp is removed, and fine instruments shape each canal while it is rinsed with disinfecting solutions. The length of each canal is measured carefully.
- Filling and sealing. The cleaned canals are filled with a rubber-like material and a sealer, which closes them off from bacteria.
- Restoring the tooth. The opening is closed with a filling, and in most back teeth a crown is recommended afterwards.
Single-sitting or multiple visits?
Many root canals can be completed in one appointment. Others are better done over two or more visits, for example when there is a lot of infection or swelling, when the canals are curved, narrow or hard to find, or when an old root canal is being redone. Between visits, a medicine is placed inside the tooth and it is closed with a temporary filling.
Both approaches are accepted. The choice depends on the tooth, not on which is quicker, and your dentist should tell you which suits your case and why.
Does a root canal hurt?
For most people, the treatment itself feels much like having a large filling. The tooth is numb, so you should feel pressure and vibration rather than pain. If you feel anything sharp, say so: the dentist can give more anaesthetic. A very inflamed tooth can occasionally be harder to numb fully, and dentists have additional techniques for this. For people who are very anxious, sedation can be discussed in advance.
It helps to remember that the severe pain people associate with root canals is usually the pain of the infection, which the treatment is designed to relieve. Afterwards, the tooth and gum may feel tender for a few days, particularly when biting. This usually settles with the painkillers your dentist recommends. Pain that gets worse rather than better, or new swelling, should be checked.
Do you need a crown after a root canal?
Often, yes, particularly for back teeth. A tooth that needed a root canal has usually already lost structure to decay or old fillings, and the access opening removes a little more. Molars and premolars take heavy biting forces and are at risk of cracking without a crown to hold them together. Front teeth with little damage can sometimes be restored with a filling alone. Your dentist will advise based on how much healthy tooth remains.
At The Sterling Dental Clinic, a metal-ceramic crown is ₹15,000 and a zirconia full-ceramic crown ₹20,000, and a CEREC crown can often be made and fitted on the same day. The fee for the root canal itself depends on the tooth and its complexity, and is confirmed after an examination and X-ray.
What are the alternatives to a root canal?
The main alternative is to remove the tooth. Extraction removes the source of infection, but it leaves a gap. Over time neighbouring teeth can drift, the opposite tooth can over-erupt, chewing can become harder and the bone where the tooth was gradually shrinks. To replace the tooth you would then consider:
- a dental implant with a crown, which replaces the root and does not involve the neighbouring teeth
- a bridge, which is fixed to the teeth on either side and usually means shaping them
- a removable partial denture
When a tooth can be saved predictably, keeping it with a root canal is usually the first choice. But some teeth cannot be saved, for example when a crack runs down the root or too little tooth is left to restore. In those cases an extraction and implant may be the better long-term option. A good dentist will explain both routes honestly.
Antibiotics are not an alternative. They may be prescribed when infection is spreading, but they cannot clear an infection inside the tooth, and the problem returns if the tooth is not treated.
Aftercare following a root canal
- Do not eat until the numbness wears off, so you do not bite your cheek or tongue.
- Avoid chewing hard food on the tooth until it has its final filling or crown. A tooth with a temporary filling is fragile.
- Brush and floss normally, gently around the treated tooth.
- Take painkillers or any prescribed medicine exactly as advised.
- Go back promptly to have the crown or final restoration placed. Delay is a common reason treated teeth break or become reinfected.
Contact your dentist if swelling appears or increases, pain worsens after a few days, the temporary filling falls out or your bite feels high.
Root canals at Sterling
Root canal treatment is a core speciality at The Sterling Dental Clinic in Vasant Vihar, where it is carried out by endodontists with an MDS in Conservative Dentistry and Endodontics. Many cases are completed in a single sitting, and complex ones are planned over more than one visit. If you have a lingering toothache, an early examination keeps the most options open. Read more about root canal treatment at Sterling.
Common questions
How long does a root-canal-treated tooth last?+
A well-treated tooth that is properly restored, usually with a crown on a back tooth, can last for many years, often as long as your other teeth. Nobody can promise an exact lifespan. What helps most is getting the final restoration fitted promptly, keeping the tooth clean, not chewing very hard objects and attending regular check-ups so problems are found early.
Can a root canal fail?+
Sometimes. Bacteria can remain in a hidden or very narrow canal, a leaking filling or crown can let them back in, or the tooth can crack. Symptoms include returning pain, swelling or a gum boil. Many such teeth can be treated again, a procedure called retreatment, and some need a small surgical procedure at the root tip. If a tooth cannot be saved, it can be replaced.
Can I eat after a root canal?+
Yes, once the numbness has worn off, which usually takes a few hours. Start with soft food and chew on the other side. Avoid hard, sticky or very chewy food on the treated tooth until the final filling or crown is in place, because a tooth with a temporary filling can break. If your bite feels high or uneven, let your dentist know.
Can a front tooth need a root canal?+
Yes. Front teeth can need a root canal after deep decay, but injury is a common cause: a knock to the mouth, even years earlier, can damage the pulp without visible breakage. A front tooth that has slowly turned grey or dark is one sign. Front teeth usually have a single canal, and some can be restored with a filling rather than a crown afterwards.
Why do some root canals take two or three visits?+
Extra visits are usually planned when the tooth has a lot of infection or swelling, when its canals are curved, narrow or difficult to locate, or when an earlier root canal is being redone. Between appointments, a medicine is left inside the tooth to help disinfect it. Splitting treatment this way is a clinical decision about the tooth, not a sign that anything has gone wrong.
This article is general information, not a diagnosis. Your own treatment plan is agreed after an examination at the clinic.