Page 33 - My FlipBook

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NOMENCLATURE. : 9

A lingual wall,
A labial wall,
A gingival wall,
And —
An axial wall.
In the step portion
A labial wall,
A lingual wall,
A mesial (or distal) wall.
And —
A pulpal wall.
Labial and lingual cavities in the incisors and cuspids
have —
A mesial wall,
A distal wall,
A gingival wall.
An incisal wall,
And —
An axial wall.
ANGLES OF CAVITIES.
In naming cavity walls and angles, the typical idea of the
cavity is that of a cuboid space, or the form of a box. No matter
how irregular the actual form of the cavity, its walls and angles
are named as if the form were regular.
Each simple cavity has two sets of line angles and one set
of point angles.
Rule: All line angles are formed by the junction of two
walls along a line, and are named by combining the names of
the walls joining to form the angle. They are, therefore, named
in two terms.
Rule : All point angles are formed by the junction of three
walls at a point, and are named by joining the names of the walls
forming the angle. They are, therefore, named in three terms.
In simple cavities one set of line angles is formed by the
junction of the four surrounding walls with each other, forming
lines which run from the enamel margin to the pulpal wall in
occlusal cavities, or to the axial wall in axial cavities. A second
set of line angles is formed by the jimction of the surrounding
walls with the pulpal wall in occlusal cavities, or with the axial
wall in cavities in the axial surfaces of the teeth.
The point angles are formed where the line angles of one set
meet the other set at the angles of the cavity. The broader rule
for naming angles, to which there is but a single exception, is