Page 42 - My FlipBook

14 THE TECHNICAL PROCEDURES IN FILLING TEETH.

need to be mentioned. However, the student should be able to
understand just what is meant when any one of them is men-
tioned, OT be able to name any of them in any cavity. This he
will not do by memorizing lists that are given, but by so learning
the application of the rules as to be able to correctly apply a
name to any angle of any cavity.
Nomenclature op Enamel Margins.

The enamel margin includes the whole outline of the cavity
and is equivalent to the marginal lines of the cavity. In this
sense the enamel margin marks the outlines of the cavity.
The cavo-surface angle of a cavity, or of the enamel, is
the angle formed by the junction of the wall of the cavity with
the surface of the tooth. Figure 8, c. s. The cavo-surface angle
of a cavity will ordinarily be of enamel ; under some unusual
conditions it may be of dentin ; or, in cavities that extend beyond
the gingival line, the cavo-surface angle will be of cementum.
The term cavo-surface angle is used especially when it is desired
to indicate the form to be given this angle in any particular por-
tion of the enamel margin, or outline of a cavity ; as, the buccal
cavo-surface angle is to be beveled.
The dento-enamel junction is the line of junction of the
dentin and enamel as it appears in the walls of cavities. Figure
8, D. E.
The enamel wall is that portion of the wall of a cavity
which consists of enamel, e. w. It includes the thickness of the
enamel from the dento-enamel junction to the cavo-surface angle.
The dentin wall is that portion of the wall of a cavity
which consists of dentin, d. w.
The dentin wall of a cavity and the enamel wall may be
on the same inclination and continuous as on the left hand of
Figure 8, supposing that to be the wall of a cavity. Or the
dentin wall may be on one inclination and the enamel wall on
another, as shown by d. av. for the dentin wall and e. w. for the
enamel wall, supposing these to constitute the cavity wall.

The Planes of the Teeth and the Inclination of
Cavity Walls.

The teeth have three planes which may frequently be used
to advantage in cavity description, and especially in speaking of
the inclination of cavity walls.
The horizontal plane, Figure 9, is at right angles to the