b. Anterior and Posterior Teeth. As indicated in paragraph 4-1, teeth may be
divided into anterior and posterior groups. Anterior teeth, commonly called "anteriors"
when referred to as a group, include the central and lateral incisors and the cuspids.
Posterior teeth, commonly called "posteriors" when referred to as a group, include the
bicuspids and molars. Anterior teeth differ from posterior teeth in their relative position
within the dental arch. They also differ in their form, their function, and their conformity
to that part of the arch in which they are located.
(1) Anterior teeth. Anterior teeth are characterized by having single roots
and incisal edges or single-cusped crowns ending in narrow edges. These narrow
edges are designed to incise (bite off) relatively large amounts of food in eating.
Anterior teeth are located in the anterior part of the jaw. They are so aligned as to form
a smooth curving arch from the distal of the cuspid of one side of the arch to the distal
of the cuspid on the opposite side.
(2) Posterior teeth. Posterior teeth differ from anterior teeth in that they may
have more than one root. They also differ in their form and function. They may also
have multiple cusps forming occlusal surfaces designed to crush and grind food into
(a) Bicuspids. Most bicuspids have single roots but may have roots
which are partly or completely bifurcated (over one-half of all maxillary first bicuspids
have such bifurcations). As their name implies, most bicuspids have two cusps. The
mandibular second bicuspid may have either two or three cusps. The three-cusped
bicuspid has two lingual cusps and one buccal cusp.
(b) Molars. Molars are all multirooted (three roots in the maxillary arch
and two roots in the mandibular arch). See figure 4-1. Molars have four or more cusps.
First permanent mandibular molars have five functional cusps. The maxillary first
molars have four functional cusps and the cusp of Carabelli, a nonfunctional cusp
located on the mesioloingual surface. Third molars are commonly called "wisdom
teeth." They resemble second molars but are largely unpredictable as to form, size, and
number of roots.
Figure 4-1. Trifurcated and bifurcated roots.