Teeth are made of hard and soft tissues. The hard tissues are enamel, dentin, and cement; they are found in the outermost part that protects the soft tissue: the dental pulp.
The dental pulp is a set of small arteries, veins, and nerves found in the innermost part of the tooth. It is contained in a space known as the pulp chamber and runs along each of the roots of the teeth, through spaces known as root canals.
Caries Caries are the formation of holes in the teeth, caused mainly by poor hygiene. When these pits expose the dental pulp to the oral environment and temperature changes, it becomes inflamed
Trauma When teeth receive severe blows, they can become disconnected from the vessels that provide their blood supply, resulting in pulpal necrosis.
When a tooth is dead, it loses sensitivity to temperature changes. Many times, dead teeth have experienced severe pain in the past, but if the necessary treatment was not carried out in time, the inflammation caused the nerve of the tooth to die, and it lost all sensitivity.