The dental pulp is the innermost part of the tooth. It is housed inside the hard chamber of the tooth which is composed of enamel and dentine. This hard casing around the pulp protects it from infection by microbes present in the mouth. In the case of tooth decay, this outer cover erodes away to form holes or cavities that can expose the dental pulp to these microbes as well as to extreme temperatures of food.
Structure of the dental pulp
The dental pulp develops from the neural crest cells in the fetus which condense to form the dental papilla. The mature pulp has a layer of highly specialized cells called odontoblasts that lie around the outer borders of the pulp. The dental pulp itself has a rich supply of blood vessels and nerves.
Functions of the dental pulp
After root canal treatment to remove affected dental pulp, the tooth does continue to function. Although the pulp has been removed, the periodontal ligament and the surrounding tissues continue to support the tooth which raises the question of why the dental pulp is necessary in a fully formed tooth. However, studies have shown that teeth with intact pulp are better equipped to fight off bacterial invasion than teeth without pulp. Therefore, the most important function of the pulp is to provide defence against invading microbes.
Disease and damage to the dental pulp
As enamel and dentine become damaged by factors such as injury, cracks, fractures, tooth decay, and dental caries, microbes from the mouth enter the dental pulp. The pulp then becomes inflamed, leading to toothache. As infection and inflammation progress, pulp may become necrotic or die off. The infection may also spread to tissues surrounding the tooth, causing dental abscesses and infection of the root and jaw bone.
Pulp infection can be severe, even leading to oral sepsis that may become life threatening if not treated. Infection of the pulp in the upper jaw may also spread to the sinuses and cause purulent sinusitis or even spread to the brain causing meningitis or a brain abscess. The infection may also spread to the eye ball causing orbital cellulitis or to the cavernous sinus causing cavernous sinus thrombosis. Each of these conditions is life threatening.
Infections in the lower jaw may cause complications such as parapharyngeal abscess, Ludwig's angina, pericarditis (affecting tissue around the heart) or mediastinitis (affecting the chest cavity), jugular thrombophlebitis or emphysema of the lungs. Each of these conditions is also severe and needs prompt treatment.