Root canal treatment: what actually happens in the chair

Root canal treatment removes the inflamed or infected pulp, the soft tissue with nerves and blood vessels inside a tooth, then cleans, disinfects and seals the canals so you can keep the tooth. Under local anaesthesia it usually feels much like a long filling, and it typically takes one or two visits.

What root canal treatment is and when it is needed

Inside every tooth, beneath the hard enamel and dentine, there is a space filled with soft tissue called the pulp. The pulp continues down narrow channels inside the roots, the root canals, and contains nerves and blood vessels. When it becomes badly inflamed or infected, it cannot heal on its own, and the tooth needs either root canal treatment or extraction.

The most common reasons the pulp is damaged are:

• deep tooth decay (caries) that has reached the pulp;
• a crack or fracture, sometimes too small to see with the naked eye;
• a blow to the tooth, even years earlier;
• a very deep filling, or a tooth that has had several fillings or a crown over the years;
• an abscess, a pocket of infection that forms around the tip of the root.

Signs that the pulp may be involved

Typical warning signs include pain from hot or cold that lingers after the drink is gone, throbbing pain that starts on its own or wakes you at night, pain when biting, swelling of the gum or face, a small pimple on the gum that may release pus, and a tooth that slowly turns darker. Sometimes there are no symptoms at all and the problem is only found on an X-ray during a check-up.

If you are in strong pain right now, our guide on what to do about a severe toothache explains the first steps. Swelling that spreads quickly, fever, or difficulty swallowing or breathing needs urgent medical attention.

What happens in the chair, step by step

Root canal treatment follows a precise sequence, and knowing it in advance helps many anxious patients feel more in control. Details vary from tooth to tooth, but the main steps are the same everywhere, as the NHS overview of root canal treatment also describes.

1. Diagnosis and X-ray

The dentist asks about your symptoms, examines the tooth and the gum around it, and usually takes an X-ray to see the roots and the surrounding bone. Simple tests, such as touching the tooth with something cold or tapping it gently, help show whether the pulp is inflamed, infected or no longer alive. The dentist also checks that enough of the tooth remains for it to be restored afterwards.

2. Local anaesthesia

The area is numbed with local anaesthesia, an injection that blocks feeling around the tooth while you stay fully awake. Treatment starts only once the tooth is properly numb, and more anaesthetic can be added at any point.

3. Isolating the tooth

A thin rubber sheet called a dental dam is placed around the tooth and held with a small clip. It keeps saliva and bacteria out of the tooth and stops tiny instruments and cleaning liquids from reaching your mouth. You can still breathe and swallow normally.

4. Opening the tooth and finding the canals

A small opening is made in the top of the tooth to reach the pulp chamber. The dentist then locates every canal. Front teeth often have a single canal, while molars usually have three or four, sometimes more, and some canals are very narrow or curved.

5. Cleaning, shaping and disinfecting

This is usually the longest part. Fine, flexible instruments called files remove the pulp tissue and shape each canal along its full, carefully measured length. Throughout, the canals are rinsed with disinfecting solutions. You will mostly feel light pressure and hear the instruments, not pain.

6. Filling and sealing

Once the canals are clean and dry, they are filled with a rubber-like material called gutta-percha and a sealing cement, so that bacteria cannot settle inside again. A final X-ray checks the result. If the tooth needs more time, for example because of an active infection, a medicated dressing is placed inside it and the tooth is closed with a temporary filling until the next visit.

7. Rebuilding the tooth

Sealing the canals is not the end of the treatment. The tooth then needs a proper restoration, either a filling or, very often for back teeth, a crown, to protect it and to stop bacteria from leaking back in.

How long it takes

A single appointment usually lasts about one to two hours. Many teeth are treated in one or two visits, while molars, teeth with an active infection and re-treatments of previously treated teeth may need more.

Does it hurt? Pain and anaesthesia, honestly

For most people, the treatment itself feels similar to having a large filling: you feel pressure, vibration and water, but not sharp pain. The pain people associate with a root canal is usually the toothache caused by the damaged pulp before treatment, and the treatment generally relieves it.

Honesty matters here. A tooth with a very inflamed pulp can be harder to numb, especially a lower molar. In that case the dentist gives additional anaesthetic, sometimes with a different technique, and waits a little longer. You can raise your hand at any time to pause. We explain this in more detail in our article is root canal treatment painful?

Once the anaesthetic wears off, the tooth is commonly tender for a few days, especially when you bite. This is the surrounding tissue settling down, and it usually responds well to ordinary painkillers that are suitable for you, such as paracetamol or ibuprofen, taken as directed.

Recovery and aftercare

Most people return to work or study the same day. A few simple habits help the tooth settle while it waits for its final restoration:

• Wait until the numbness has gone before eating or having hot drinks, so you do not bite your cheek or tongue or burn yourself.
• Avoid chewing hard food on the treated tooth until the final filling or crown is in place, because a tooth with a temporary filling can crack.
• Keep brushing twice a day and cleaning between your teeth, including around the treated tooth.
• If the temporary filling feels loose or partly falls out, contact the clinic so it can be replaced.
• Come back for the final restoration without a long delay.

Contact the dentist if the pain gets worse rather than better after a few days, if swelling appears or increases or if your bite feels high. Antibiotics are not a substitute for root canal treatment; they are used only in specific situations, such as a spreading infection or fever.

When there was an infection around the root tip, the bone there usually needs several months to heal. The dentist may take a follow-up X-ray to check that healing is progressing.

How long does a root-canal-treated tooth last?

When the canals are well cleaned and sealed and the tooth is properly restored, most root canal treatments succeed, and the tooth can last for many years, often for life, as Cleveland Clinic explains in its guide to root canal treatment. What happens after the treatment matters as much as the treatment itself.

A treated tooth is more fragile not because it is no longer alive, but because it has often lost a lot of structure to decay, old fillings and the access opening. Back teeth take strong chewing forces, so a crown is usually recommended to hold the tooth together and prevent it from splitting. Front teeth with little damage can sometimes be restored with a filling alone. Our article on why a crown is often recommended after root canal treatment explains the reasoning.

Risks, limits and alternatives

Root canal treatment is well established, but like any treatment it has limits. Possible problems include:

• infection that persists or returns, for example because of a hidden extra canal or a leaking restoration;
• a crack in the root, which may only show up later and often means the tooth cannot be kept;
• rarely, a tiny instrument fragment left in a canal, or a small perforation of the root wall;
• gradual darkening of a front tooth, which can often be improved later.

If a treated tooth develops problems again, the options are usually re-treatment (removing the old filling material, cleaning the canals again and resealing them), a minor surgical procedure at the root tip called an apicectomy, or extraction.

Root canal treatment is not suitable when a tooth is too broken down to be restored, has a vertical crack in the root, or has lost too much supporting bone through gum disease. The alternative is extraction, followed by a decision about the gap. Our article root canal or extraction: how the decision is made goes through this choice in detail.

What determines the cost of root canal treatment

There is no single price for root canal treatment, because the cost depends on the tooth and on what it needs. After an examination and an X-ray, the dentist can explain the plan and its cost before any treatment begins. The main factors are:

• which tooth it is, since front teeth usually have fewer canals than premolars and molars;
• how complex the canals are, for example very curved, narrow or calcified canals;
• whether it is a first treatment or a re-treatment of a tooth treated before;
• how many visits are needed, for instance when an infection requires a medicated dressing between appointments;
• the final restoration: a filling, a post and core build-up, or a crown, and the crown material.

Root canal treatment at Ajam Dental Clinic in Tripoli

At Ajam Dental Clinic, root canal treatment, including re-treatment of previously treated teeth, is carried out by a visiting specialist endodontist, a dentist who focuses on treating the inside of the tooth. When a crown is needed afterwards, it is part of our prosthodontic work, and Dr. Abdel Rahman Ajam’s focus is prosthodontics and aesthetic dentistry, including crowns. For children, all dental care is handled by Dr. Soumaya Ajam, whose specialty is paediatric dentistry.

You can read more about our root canal treatment and re-treatment or meet the team on our about page. Patients come to our clinic on Fouad Chehab Boulevard, Al-Makateb Building, 1st Floor, from across Tripoli — El Mina, Abu Samra, Al-Tall, Zahriyeh and Bahsas — as well as from Qalamoun and the rest of North Lebanon. If a tooth is bothering you, contact us by WhatsApp or phone to book a consultation.

This article provides general information for patients. It does not replace an examination by a dentist, who can advise you on your own situation.