Page 19 - My FlipBook

NOMENXLATURE. 15

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.
Hence a mesio or disto-occlusal cavity has in its mesial or
distal portion —
A bucco-gingival angle )
^^^ ^^^ ^^ ^^^ ^^^j^^^
A linguo-gingival angle
An axio-buccal angle
An axio-lingual angle j. 2d set of line angles.
An axio-gingival angle j
An axio-bucco-gingival angle ~i .
^ .^ ^ ^^
. . ,. . , [ Pomt angles.
An axio-lmguo-gmgival angle -•
,
And in the step portion —
A mesio- (or disto-) buccal angle
"t
A mesio- (or disto-) lingual angle * ist set of line angles.
A mesio- (or disto-) pulpal angle
1
A linguo-pulpal angle l
^d set of line angles.
A bucco-pulpal angle
J
A mesio- (or disto-) bucco-pulpal angle
]
^^^"^ angles.
A mesio- (or disto-) linguo-pulpal angle j
And a pulpo-axial angle formed by the junction of the pulpal
wall of the step with the axial wall of the mesial or distal cavity.
The rule illustrated in the above is universal. A buccal
cavity united with an occlusal cavity would also have its pulpo-
axial angle. The angles belonging to the occlusal wall of the
buccal cavity would be missing, and the angles belonging to the
buccal wall of the occlusal cavity would also be missing. This,
however, makes no difference whatever with the naming of the
remaining angles. If, however, the pulp of the tooth is removed,
removing the axial and pulpal walls, the angles with these walls
are also removed and the angles of the pulp chamber (sub-pulpal
angles) substituted.
in the incisors and cuspids have —
Labial or lingual cavities
A mesio-gingival angle
A disto-gingival angle . ,.
....
^
. , I ist set of Ime angles.
A mesio-mcisal angle
A disto-inclsal angle