A tooth is divided into two parts – the crown and the root. Crown is that part of a tooth seen above the gum level in the oral cavity, and root is that part of the tooth which is below the gum level and surrounded by the bone.

The tooth primarily consists of four layers – enamel, dentin, pulp and, cementum. Cementum is the layer that covers the root of the tooth, while enamel covers the crown of the tooth. Below the enamel lies the dentin, and below the dentin lies the pulp.

A root canal is the hollow part of a tooth, consisting of blood vessels, nerves and, the pulp tissue.

The pulp mainly is divided into the pulp horns, the pulp chamber and the pulp /root canal (from crown downwards) and it provides nourishment to the tooth, and the nerves inside the pulp give the hot or cold sensation to the tooth.

When the pulp tissue gets infected or inflamed, a root canal treatment is required to remove the infection from the tooth, prevent reinfection and save the natural tooth.

There are three main layers on the crown portion of the tooth surface. When the decay on the tooth surface is either in the first layer (Enamel) or second layer (Dentin), a dental filling will suffice in stopping the decay and restoring the tooth, but once the decay reaches the third layer (Pulp) a root canal treatment is needed to save the tooth. Infection in the pulp invariably leads to an inflamed pulp which leads to an abscess formation at the tip of the root of the tooth. If still left untreated, the abscess may turn into a cyst causing more damage to the tooth and it’s surrounding tissue. Formation of an abscess or cyst can also lead to an intra-oral or extra-oral swelling in patients. Sometimes, infection in the pulp makes the tooth dead. There may be no other symptoms except discoloration of that tooth. It is important to undergo root canal treatment for this tooth as well before the infection starts spreading to the surrounding tissue. One must, therefore, restore a tooth using a permanent dental filling as soon as the decay starts, to avoid this decay from spreading further to the pulp and reducing the risk of a root canal treatment. In the inevitable condition when the decay does reach the pulp, these are a few symptoms that the patient may experience once the pulp is infected, a root canal treatment requirement :

• Severe pain while chewing or biting
• Boils on gums (abscess)
• Deep decay
• Prolonged sensitivity to hot or cold foodstuff
• Swollen gums

It is the dentist who takes the final call on whether or not a tooth requires a root canal, by use of clinical examination of the tooth and the gums surrounding the tooth, by use of dental x-rays and use of some other dental procedures such as pain on percussion, pulp exposure, etc.

Root canal treatment is done in a step by step manner, and it takes between one and three sessions to complete.

 

• Root canal opening

 

Under Local anaesthesia, an opening is made on the tooth surface using a dental handpiece and burs, and all the infected pulp tissue is removed. The tooth is also de-occluded from its opposing tooth to prevent any kind of biting or chewing pressure on the tooth undergoing root canal treatment.

 

• Cleaning and Shaping of the root canal

 

Next, the dentist will clean, shape and decontaminate the root canal using dental files in a step by step manner, also increasing the width of the canal and by using irrigation solutions (like sodium hypochlorite and saline), making the root canal bacteria-free.

After this step, the patient will no longer feel any pain in that tooth because the nerve tissue has been removed, and the infection has been eliminated.

• Obturation

The hollow canal is then filled by an inert filling material (usually gutta percha). In cases of severe infection, the dentist may place a medication (such as calcium hydroxide) inside the canal for a few days till the infection clears and later replace it with the permanent inert filling material.

• Filling and crown

The root canal treated tooth is then filled up on top using a permanent filling. Since the tooth becomes brittle after a root canal treatment, it is mandatory to place a crown (cap) on a root canal treated tooth. In cases where tooth structure is not adequate, a post (a metallic pin-like structure) is inserted inside the tooth to give it more support, and then a crown is placed on top.