The Healthy Tooth
To understand root canal treatment it helps to understand the anatomy of the tooth. Inside the tooth below the white hard enamel and the yellow dentin is a soft tissue called the pulp. The pulp contains blood vessels, nerves and connective tissue. It is responsible for the creation of the dentin and enamel early in life. The pulp is continuous with the blood vessels, nerves and connective tissue of the jaw bone and the tip of the root. Since the pulp’s only function is the formation of the tooth, its job is done when the tooth is fully formed. To that end the tooth can survive without the pulp since it can receive its nutrients from the surrounding jaw bone and associated tissues.
The Infected or Inflamed Tooth
If a tooth becomes damaged due to either a crack or decay, the bacteria from your saliva will come in contact with the pulp. This causes the pulp to become inflamed and eventually die. Once dead this tissue is able to sustain the bacteria and leads to an infected tooth and eventually an abscess in the jaw bone.
Signs of pulp damage are: lingering pain after eating or drinking hot or cold foods or aching for no reason at all. Signs of an abscess can be significant pain on biting and/or swelling of the adjacent gums or face.
Occasionally, if the tooth dies very slowly (i.e. a silent death) the only sign of pulp damage might be a discolored tooth or a shadow (radiolucency) at the tip of the root on a dental x-ray.