Sources: American Heart Association. Heart Disease and Stroke Statistics - 2009 Update; CDC, Heart Disease and Stroke Prevention Addressing the Nation's Leading Killers, At A Glance, 2011. Heart disease and stroke are the first and fourth leading causes of death in the United States.
Your teeth are composed of four dental tissues. Three of themâenamel, dentin and cementumâare hard tissues. The fourth tissueâpulp, or the center of the tooth that contains nerves, blood vessels and connective tissueâis a soft, or non-calcified, tissue.
The top part of the tooth is the crown. This is the part that is visible in your mouth. The bottom part of the tooth is the root. A tooth is composed of the outer layer of the crown called enamel, the middle layer called dentin, and the inside layer called the pulp. The pulp contains the nerves and blood vessels for the tooth. The outer layer of the root is the called the cementum.