When the pulp becomes inflamed, pressure begins to build up in the pulp cavity, exerting pressure on the nerve of the tooth and the surrounding tissues.
Unlike other parts of the body where pressure can dissipate through the surrounding soft tissues, the pulp cavity is very different.
The other group had a different cusp arrangement and had a pulp cavity, these are called orthodont teeth.
It is a progressive disease, usually starting with loss of cementum and dentin and leading to penetration of the pulp cavity.
One group had teeth with acuminate cusps that lacked a pulp cavity; these are called osteodont teeth.
The infection probably developed because the pulp cavity of a broken dentary tooth was exposed to bacteria.
Also, the overall pulp cavity may be smaller by the addition of secondary or tertiary dentin, thus causing pulp recession.
The pulp cavity inherently provides the body with an immune system response challenge, which makes it very difficult for a bacterial infection to be eliminated.
