Page 39 - My FlipBook

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NOMENCLATURE. 11

First set of line angles
A linguo-gingival angle,
A buceo-gingival angle,
A linguo-ocelusal angle,
A bucco-occlusal angle.
Second set of line angles:
An axio-lingual angle.
An axio-occlnsal angle.
An axio-buccal angle,
An axio-gingival angle.
Point angles
An axio-linguo-gingival angle,
An axio-bucco-gingival angle,
An axio-linguo-occlusal angle.
An axio-bucco-occlusal angle.
But in mesial and distal cavities in the bicuspids and molars
as prepared for filling, the occlusal wall is generally cut away
and a step formed in the occlusal surface, forming a complex
cavity. In this case, the occlusal wall is missing and all of the
angles formed by the junction of this wall with others are also
missing. Then the step in the occlusal surface has its angles
the same as in a simple occlusal cavity, except that the angles
pertaining to the missing wall, mesial or distal, are also missing.
This is a universal rule with complex cavities. Line angles are
shown in Figure 4. Point angles are shown in Figure 5. See
also Figures 6, 7.
—
Hence a mesio- or disto-occlusal cavity has
In the mesial or distal portion
First set of line angles
A bucco-gingival angle, b. g.
A linguo-gingival angle, l. g.
Second set of line angles:
A buceo-axial angle, b. a.
A linguo-axial angle, l. a.
A gingivo-axial angle, g. a.
Point angles
A gingivo-bucco-axial angle, g. b. a.
A gingivo-linguo-axial angle, g. l. a.
In the step portion:
First set of line angles
A bucco-distal (or mesial) angle, b. d.
A linguo-distal (or mesial) angle, l. d.