The chief function of the pulp is the formation of
dentin. However, it also furnishes nourishment to the
dentin; provides sensation to the tooth, and responds to
irritation, either by forming reparative secondary
dentin or by becoming inflamed. The pulp chamber
contains the coronal pulp and pulp horns located
within the crown portion of the tooth. The apical
foramen is at the end or apex of the radicular pulp.
Blood vessels, nerves, and connective tissue pass
through this area to reach the interior of the tooth.
The tissues that surround and support the teeth are
collectively called the periodontium. Their main
functions are to support, protect, and provide
nourishment to the teeth. Figure 4-8 illustrates the
supporting tissues of the periodontium. The
periodontium consists of cementum, alveolar process
of the maxillae and mandible, periodontal ligament,
Cementum is the only tissue considered as both a
basic part of the tooth and a component of the
periodontium. It is a thin, calcified layer of tissue that
completely covers the dentin of the tooth root.
Cementum is forming during the development of the
root and throughout the life of the tooth. Cementum
functions as an area of attachment for the periodontal
The alveolar process (fig. 4-8) is that bony portion
of the maxilla and mandible where the teeth are
embedded and by which tooth roots are supported.
The alveolar socket is the cavity within the
alveolar process in which the root of the tooth is held
by the periodontal ligament. The bone that divides one
socket from another is called the interdental septum.
When multirooted teeth are present, the bone is called
the interradicular septum. The alveolar process
includes the cortical plate, alveolar crest, trabecular
bone, and the alveolar bone proper.
Structurally, the cortical plate is composed of
lingual and facial plates of compact bone. It is dense in
nature and provides strength and protection and acts as
the attachment for skeletal muscles. The mandibular
cortical plate is more dense than the maxilla cortical
plate and has fewer perforations for the passage of
nerves and blood vessels.
The alveolar crest is the highest point of the
alveolar ridge and joins the facial and lingual cortical
Trabecular or spongy bone lies within the central
portion of the alveolar process, and is the less dense,
Figure 4-8.The periodontium.