Sometimes despite your best efforts teeth can become diseased because of the effects of decay, cavities, injury or even extreme wear. When the dental pulp inside the tooth becomes diseased or dies you may experience tooth aches, sensitivity to hot and cold, discolouration, swelling or abscesses.
Once upon a time the only solution to this kind of tooth disease was to remove the tooth, however these days a root canal treatment can save the tooth. A root canal procedure involves removing the infected pulp, disinfecting the space, then inserting fine dental files to strengthen the tooth, then covering with a final filling.
Using a root canal to save the natural tooth is preferable to extracting and replacing the tooth because natural teeth are more efficient at biting and chewing, plus they are stronger.