What is root canal treatment, and does the tooth need a crown afterwards?

"Root canal" sounds frightening, but it is the way to keep a tooth that would otherwise have to be removed. When the pulp is inflamed or has died, the dentist removes the diseased pulp, cleans and seals the root canal system, and then restores the crown of the tooth. A tooth without its pulp still stands in the bone and can chew for many years if it is protected properly.

What the pulp is, and when it becomes inflamed

The pulp is the soft tissue inside the tooth, made of blood vessels and nerves, running from the pulp chamber in the crown down the canals in the roots. It becomes inflamed when bacteria reach it, usually through:

• Deep decay that has reached the pulp.
• A crack or fracture from injury or biting something hard.
• An old leaking filling with new decay underneath.
• Severe wear exposing dentine close to the pulp.
• Deep gum disease reaching the root tip.

Early pulp inflammation causes lingering sensitivity to hot and cold; later, spontaneous pain and pain at night. Once the pulp dies, the tooth may stop hurting for a while and then swell up with an abscess. See Toothache at night.

The steps of root canal treatment

1. Examination and X-rays to identify the tooth, the number of roots, the shape of the canals and any lesion at the root tip.
2. Anaesthetic, and isolation of the tooth with a rubber dam so saliva cannot enter the canals.
3. Opening the pulp chamber through the biting surface or the back of the tooth.
4. Removing the pulp, cleaning and shaping the canals with fine instruments and disinfecting solutions; the canal length is measured electronically.
5. Medication inside the canals between visits if the tooth is badly inflamed.
6. Filling the canals with a dedicated material once the tooth is clean and symptom-free.
7. Restoring the crown of the tooth: a filling or a crown, depending on how much tooth remains.

A single-rooted front tooth is often finished in one or two visits; a back tooth with several curved canals may need more. During treatment, avoid chewing hard on the tooth, because the temporary filling breaks easily. At Asahii Dental Clinic, before starting, the dentist shows you on the X-ray which tooth needs treatment, the expected number of visits and the cost of each item, including the restoration afterwards; the plan is written down for you to confirm, and each visit is reminded through the clinic's Zalo Mini App.

Does the tooth need a crown afterwards?

It depends on which tooth and how much of it is left.

• Back teeth (molars and premolars): they take heavy chewing forces and have usually lost a lot of structure to decay and to the access opening. A tooth without its pulp is drier and more brittle, and prone to vertical cracks; once a crack runs down the root, the tooth has to be removed. So dentists usually advise a crown, sometimes with a post in the canal, after root canal treatment.
• Front teeth: if plenty of tooth remains and the access hole is small, a filling may be enough. If the tooth is discoloured or badly broken, a crown or a veneer is considered.

A root-treated tooth left with only a temporary filling for a long time is a common reason for the tooth to fracture and be lost a few years later. See Porcelain crowns: when you need one.

Caring for a root-treated tooth

• Brush and floss it like any other tooth. A tooth without its pulp can still decay; it just no longer feels pain to warn you.
• Avoid biting hard things with it until it has been fully restored.
• Attend check-ups and X-rays as scheduled so the dentist can confirm that any lesion at the root tip has healed. At Asahii the X-rays from before and after treatment are kept in your record, so at the next check-up the dentist puts the two side by side.
• Mild tenderness on biting for a few days after treatment is normal; increasing pain or a swollen gum means you should come back.

When to see us straight away

• Severe, spontaneous pain, or pain at night.
• Swollen gum, a pimple of pus beside the tooth, or a tooth that feels high when biting.
• Facial swelling or fever.
• A root-treated tooth that starts hurting again, or a temporary filling that has fallen out.

Whether your tooth needs root canal treatment or just a filling, and whether it should then be crowned, can only be decided after an examination, pulp tests and X-rays. See our general dentistry page or book an appointment by hotline 0928 888 121, Zalo or the Mini App.