Tooth anatomy is comprised of 3 layers (think of an onion), the outer layer is enamel, next layer in is dentine and the core of the tooth is a pulp chamber (root canal). A root canal (endodontic) procedure involves taking out the nerve and blood vessels of the root canal, cleaning and shaping the canal space and then filling it up to prevent bacteria from getting back into the root system.
The purpose of this procedure is to maintain a tooth in the mouth (albeit without a living nerve). In a fully developed tooth, the tooth can survive without the pulp because the tooth continues to be nourished by the tissues surrounding it.
If pulp inflammation or infection is left untreated, it can cause pain or lead to an abscess which can also cause facial swelling.
Initial treatment is to remove the source of infection of the pulp and to determine if there is enough remaining tooth structure. If little tooth structure remains tooth removal may be a better long term option. If a fracture of the tooth has reached the pulp, or infection is associated with gum disease, it could be more difficult and sometimes impossible to save the tooth.
The general sequence of a root canal procedure is as follows:
Local anesthetic (generally two injections) is administered to numb the tooth that is to be treated. If the pulp in a tooth is very inflamed (“hot tooth”), and as a result very painful, it may take a while to get it numb and require a few more injections. Your dentist/endodontist will not start the treatment until the tooth is adequately anesthetized.
A dental dam (rubber sheet) is put in place. This is used to isolate the infected tooth from the rest of mouth to aid root canal treatment. The tooth undergoing treatment protrudes through a hole punched in the dam, isolating it from the rest of the mouth. The rubber dam seals the tooth preventing root canal irrigant and instruments entering the oral cavity. The rubber dam also allows the root canal treatment to be carried out in a sterile environment free from contamination by bacteria. Some dentists place a dental dam on before drilling the tooth while others will place the dental dam only after they have gained access to the root canal. Some dentists do the latter as it is easier to view the orientation of the tooth.
A small access hole is drilled through the biting surface (occlusal surface) of an affected back tooth or from behind a front tooth, allowing access to the pulp chamber and root canals for treatment.
The infected pulp tissue is removed from the tooth with hand files and rotary instruments used to clean out the root canals and pulp chamber. This step is not painful; as the tooth and surrounding tissues are numb. Once the pulp, along with the nerves contained in it, is removed, the tooth itself can no longer feel pain.
The canals are disinfected with antiseptic and antibacterial solutions.
The canals are then shaped with tiny flexible hand and rotary instruments to further clean the canals as well as allow them to receive root canal fillings and sealers. The canals are washed and cleaned after each instrumentation to remove root canal debris lodged in lateral canals.
A temporary dressing (antibacterial) material is placed down the cleaned and shaped root canals followed by a temporary filling to seal the tooth. The tooth is then left 2-4 weeks.
Step 1, 2, 3 is repeated. The temporary dressing is removed. Root canal fillings are selected that will fit exactly into the freshly prepared canals. Usually a rubber-like material called gutta-percha is used to fill the canal space. It is a thermoplastic material (“thermo” – heat; “plastic” – to shape), which generally is heated and then compressed into and against the walls of the root canals to seal them. Together with adhesive cement called a sealer, the gutta-percha fills the prepared canal space. Sealing the canals is very important to prevent them from becoming reinfected with bacteria.
A permanent filling material will then be placed to seal the access hole that was made to treat the canals, and the dental dam is removed. If the tooth lacks sufficient structure to hold a restoration (filling) in place, the dentist or endodontist may place a post (either metal or a very strong plastic) in one of the canals inside the tooth to help retain it.
After the procedure, it is normal to have some minor discomfort after treatment including slight soreness that can usually be managed with over-the-counter (paracetamol, ibuprofen) medications or prescription (codeine-type) drugs, or a combination of the two.
Your tooth will most often need a permanent restoration (a large filling or onlay or a crown) to replace the lost tooth structure, provide a complete seal to the top of the tooth, and to strengthen the tooth. If you have been treated by an endodontist, the endodontist will send you back to your general dentist to complete this step. This step is of particular importance since many studies show that root canalled teeth are more fragile than untouched teeth therefore at greater risk of fracturing or cracking.
The cost of root canals varies between dentists and endodontists and between teeth treated (incisors, canines, premolars, molars). A molar can have more than 3 root canals, a premolar and incisor up to 2 canals. The more canals to treat the longer the procedure. Endodontists tend to charge more for their service as they have completed 3 years additional post graduate training and tend to own more expensive equipment such as a microscope and 3D Xray.
Below is a general idea of New Zealand fees:
Root filling – single root (excluding restoration) $634
Root filling – Molar (3 roots) (excluding restoration) $1,018
Cast Post and Core $387
Post with Direct Core $293
Fillings – the majority of dentists charge different fees depending on the type of filling material and the number of surfaces the filling will span (4 surfaces is a very large filling, 1 surface is the smallest filling and 2 surfaces is the most common filling placed):
Amalgam filling, one surface $143
Amalgam filling, two surfaces $189
Amalgam filling including pins $263
Composite – one surface $165
Composite – two surface $219
Composite – multisurfaced $282
Composite crown $378
Glass ionomer – one surface $139
All Ceramic crown $1,338
Porcelain Fused to Metal crown $1,298