Root Canal Treatment

Endodontic Treatment

In this section we will look at:

1. What is a root canal treatment?
2. Why do I need a root canal treatment?
3. What are the risks and benefits?
4. What does the procedure involve?
5. What should I expect after the procedure?
6. How long will it last?
7. Do I need to see a specialist?
8. What if my root canal treatment fails?
9. What is a re-root canal treatment?

Why do I need root canal treatment?

You will need a root canal treatment if the nerve of the tooth has been damaged beyond repair. This could be due to:

1. Tooth decay (most common reason for root canal treatment in back teeth)
2. Cracked tooth
   
3. Dental trauma (usually front teeth)
4. Extensive restorative work such as a dental crown or bridge

There are also times where you may need an elective root canal treatment. This is where there is no damage to the nerve but a root canal treatment is required to be able to carry out other dental treatment. For example: 

1. If your tooth is heavily broken down and requires a post to hold a restoration in place 
2. To provide support for an overdenture
3. If you are suffering from extreme hypersensitivity and no other treatments have worked

If you do not want to have root canal treatment to save the tooth (or if the tooth is beyond saving), the alternative treatment option is removing the tooth.

What is the procedure?

A root canal treatment can be completed in one appointment if it is relatively simple or over multiple appointments if the tooth is harder to clean or if there is a large area of infection. 

As a general rule, teeth with a single root canal (such as your upper incisors) are easier to treat than molars which have 3 or 4 root canals.

Before your dentist starts a root canal treatment, they will have taken one or more xrays of the tooth to check for decay, infection and to assess the length and shape of the root canal. They will also take a series of xrays throughout treatment to ensure they are cleaning and filling the whole root. 

Stage 2: Isolating the tooth (rubber dam)
Root canal treatment should, in most cases, be completed under a rubber dam. Your dentist will place a rubber dam (rubber sheet) and metal band around your tooth to isolate it from the rest of the mouth. This helps to:

• keep the tooth dry
• prevent bacteria entering the root canal system 
• keep the cheeks/tongue out of the way 
• let your dentist see the tooth more clearly 
• protect your airway when using small instruments and disinfectant solution

Stage 3: Opening the tooth and locating the root canal(s)
Your dentist will use the dental handpiece to remove any decay and make an opening in the top of the tooth to access the nerve and find the main root canals. This opening is known as the "access cavity". Some teeth have only 1 canal, whilst others may have up to 4. Whilst it is impossible to clean out the whole root canal system, it is important to find and clean the main canals for the best chance of success.

Stage 4: Extirpation (removing the infected nerve)
This is removing the damaged, infected nerve from within the canal using an endodontic file (a very small, thin metal brush). For teeth with chronic infection, the nerve and blood supply may have already died leaving a hollow space within the canal.

When you visit your dentist in an emergency with an infected tooth, they can remove the infected nerve to relieve your toothache. They will place an antibacterial medicine inside the canal (such as calcium hydroxide or an antibiotic/steroid paste) and a temporary filling on top to prevent bacteria from getting inside the tooth in between appointments. This gives you time to consider whether you would like to save the tooth or have it removed (dental extraction).

Stage 5: Cleaning and shaping

This is the longest stage of the procedure where the narrow canals are cleaned and widened with a series of endodontic hand files or rotary files. Using hand files alone takes a lot longer than using rotary files which are used with a special handpiece.

This stage aims to:

• remove bacteria which are clinging to the walls of the canal
• allow the disinfectant to get all the way to the end of the canal
• widen the canal for the root filling

To make sure the whole of the canal is being cleaned, your dentist may use a special machine (called an "electronic apex locator") or take an xray. The apex locator makes lots of beeping noises which tell the dentist whether they are close to the tip of the root. 

Throughout treatment, your dentist will flush a disinfectant solution through the tooth all the way to the tip of the root. A syringe with a fine tip is used as it can be placed all the way along the canal for ideal disinfection. There are a number of different solutions your dentist may use to disinfect the canal. Sodium hypochlorite (a medical grade bleach) is most common. Others include chlorhexidine, iodine and EDTA.

Whilst your dentist will take every precaution to avoid drips and spillages, I'd advise you don't wear your best clothes to your root canal treatment appointment as they may get stained!

Stage 6: Root filling

This is one of the final stages of the root canal treatment procedure. The most common material for a root canal filling is "gutta percha" - an orange-coloured rubber.

Before filling the canal, your dentist will take another xray to make sure the filling material goes almost to the tip of the root. They will then dry the canal and fill it with gutta percha. A special glue/cement is used to help the filling stick to the canal walls and fill any micro-gaps.

Stage 7: Filling the tooth
Once the root filling is completed, your dentist will place a filling to seal the opening in the top of the tooth. This can be a composite (white filling) or amalgam (silver filling).

For a back tooth, an onlay or crown is recommended to prevent the tooth from fracturing. 

How long will it last?

There are many factors to consider when thinking about how long a root canal treatment will last. Factors affecting the success rate include:

• How big the hole is/how much of the natural tooth is left 
• How large the infection was 
• Whether there were any complications during treatment
• If you had an onlay/crown placed (for back teeth)
  Molars without an onlay/crown are twice as likely to fail compared to molars with an onlay/crown. So if you want the tooth to last as long as possible after root canal treatment, it's worth having an onlay/crown placed!  
  
• How clean you keep your teet and how much sugar you eat
  The cleaner you keep your teeth and the less sugar you eat, the more likely the treatment will be a success - and it's less likely you will need another root canal treatment in the future!

In general, the success rate of a root canal treatment, completed to a good standard, is 85-95% after 8 years. This means about 9 out of 10 teeth which have been root treated survive for 8 years or more. 

For re-root canal treatment (see below), the success rate drops to 70 to 80%. 

What if my root canal treatment fails? 

If the tooth becomes re-infected, there are 3 possible treatment options:

1. Re-root canal treatment (see below)
2. Apicectomy
3. Dental extraction 

Further treatment is usually needed if:

• You are still getting pain from the tooth
• The infection isn't healing 
  You may get a dental abscess or sinus (small hole in the gum through which the infection is draining) or an xray will show the infection staying the same size or growing larger. 

There are many reasons your root canal treatment may have failed. Reasons for re-infection include:

• complications during initial treatment
• bacteria left within the canal or around the tooth's root (more common in teeth which had a large of infection)
• missed canal in teeth with multiple root canals (some canals are tiny and difficult to locate, even with magnifying glasses)
• bacteria getting into a crack or around the filling (there is a high chance of this is you have a high sugar diet or are not brushing your teeth very well)