THE DENTAL PULP
Figure 4-6.Tissues of the teeth.
Cementum is the bonelike tissue that covers the
roots of the teeth in a thin layer (fig. 4-6). It is light
yellow in color, slightly lighter than dentin. The
cementum is composed of approximately 55% organic
material and 45% inorganic material. (The inorganic
components are mainly calcium salts.) The cementum
joins the enamel at the cervix of the tooth. The point at
which they join is called the cementoenamel junction
(CEJ). In most teeth the cementum overlaps the
enamel for a short distance. In some, the enamel meets
the cementum in a sharp line. In a few, a gap may be
present between the enamel and the cementum,
exposing a narrow area of root dentin. Such areas may
be very sensitive to thermal, chemical, or mechanical
The main function of cementum is to anchor the
teeth to the bony walls of the tooth sockets in the
periodontium. This is accomplished by means of the
fibers of the periodontal ligament or membrane.
Cementum is formed continuously throughout the life
of the tooth to compensate for the loss of tooth
substance because of occlusal wear, and to allow for
the attachment of new fibers of the periodontal
ligament to the surface of the root.
The dental pulp, (figure 4-7), is the soft tissue of
the tooth, which develops from the connective tissue of
the dental papilla. Within the crown, the chamber
containing the dental pulp is called the pulp chamber.
The pulp contains blood vessels and nerves that enter
through the apical foramen. The coronal pulp is within
the crown. Within the root is the radicular pulp.
Figure 4-7.Dental pulp.