Page 432 - My FlipBook

280 PATHOLOGY OF THE HARD TISSUES OF THE TEETH.
formation of the mesio-bucco-occlusal angle; a point angle. The so-ealled angles
of the teeth are generally smoothly rounded but are named as if they were definite
angles.
Note: The compound words formed from the adjectives ending in al, as buccal, labial, lingual,
mesial, distal, gingival, axial, pulpal, occlusal, incisal, proximal, have in recent years assumed large
proportions in usage in dental nomenclature because of their convenience in the accurate designation
of angles of the teeth, margins and angles of surfaces of teeth, of naming complex cavities, cavity
walls, cavity angles, directions on surfaces of teeth, etc., also in the adverbial forms ending in ly;
as mesi3lly, distally, etc., in compounds or in the simple forms, for indicating directions on, or in
the teeth, or any directions in the mouth. In the use of these, hundreds of combinations have been
employed, any of which can be used without confusion if used intelligently. This only requires care
as to confusing with each other angles of teeth, angles of surfaces of teeth, angles of cavities in
teeth and other similar things. At present there seems to be no need for the use of very many
of these compound forms, but it is by no means certain that the time has come for forming rules
for the limitation of their use. Something more than two-thirds of them are repetitions of the
same meaning by changing the form of the compound, as: mesio-buccal and bucco-mesial angle of
a tooth ; such changes in the relation of the words give no change whatever in the angles named.
Again, in naming the point angles of cavities, axio-mesio-^ingival angle may also be written: axio-
gingivo-mesial, mesio-axio-gingival, mesio-gingivo-axial, gingivo-mesio- axial or gingivo-axio- mesial.
These varying forms each mean the same thing precisely and any one of them expresses the thought
as perfectly as any other. The use of any one of them instead of any other one gives rfse to no
confusion whatever. A few very simple rules would cut off nearly all of this class of multiplication
of compound forms. But I have always felt that this would place an additional tax on the student
in learning the use of compound terms. I have, therefore, waited for custom, or ideas of euphony,
to suggest a method of doing this. This book has been written without any effort in this direction.
The rules in my mind may, however, be suggested here, but are given only as suggestions.
1. Whenever axial occurs, it should be placed first in the compound.
2. Wherever pulpal occurs in the absence of axial, it should be placed first.
3. Wherever mesial or distal occurs in the absence of axial or pulpal, the one occurring should
come first in the compound.
4. Wherever the three- syllable words, gingival or occlusal, occur, they should be placed last.
As simple as these rules are, they would be a considerable tax on the student in the beginning
of his use of compound terms, but there is no doubt but that with this restriction, the use of these
terms would finally become easier.
Until recently I had supposed that the use of the adverbs of direction had been suggested first
in dentistry, but it now seems that the botanists have the priority. The use made of them in botany
is not essentially different. The adverbs of direction may be used freely as single words or in
compound forms in which the last word only takes the ly, as mesio- distally ; from mesial to distal,
or mesio -lingu ally ; a diagonal direction from mesial to lingual across or through a tooth, etc.
Generally but few of these compound words are used in any one cavity description, and they are
in no way burdensome after one becomes accustomed to their use. They are the only terms in which
cavities can be sufficiently described, or in which cavity preparation can be efficiently taught. There
is often a tendency to the multiplication of these terms noticed among students by naming unes-
sential parts of cavities, such as naming individually every cavo-surface line and point angle of a
cavity ; as bucco-occlusal cavo-surface angle, bucco-mesial cavo-surface angle, bucco-mesio -occlusal
cavo-surface angle, etc. This is well enough as an exercise, but is a waste of energy in any essential
cavity description. There has been no effort to include all of these compound terms in this glossary;
only a few of the most essential are given.
Angles of cavities; rules fob naming. See Rules for Naming Angles of
Cavities. See also names of angles of cavities.
Angles of shanks of instruments. Named according to number and direction
of angles, as monangle, binangle, triple-angle, contra-angle, etc.
Angles of surfaces of teeth. Each surface of a tooth has four angles. The
angles of the occlusal surfaces of the bicuspids and molars are, the mesio-buccal,
disto-buccal, mesio-lingual and the disto-lingual. The angles of the buccal and
lingual surfaces are, the mesio-occlusal, disto-occlusal, mesio-gingival and disto-
gingival. The angles of the mesial and distal surfaces are, the bucco-occlusal,
linguo-occlusal, bucco-gingival and linguo-gingival. The angles of the labial and
lingual surfaces of the incisors are, the mesio-incisal, disto-incisal, mesio-gingival
and disto-gingival.
On account of the triangular form of mesial and distal surfaces of the incisors,
these have but three angles; the labio-gingival, linguo-gingival and incisal angle.
The incisal angle named here is an exception to the rules in that it is named in a
single term. It is formed by the junction of the labial and lingual surfaces at the
incisal edge. See Angles of Teeth, and note carefully the difference between angles
of teeth and angles of surfaces of teeth.
Angles of teeth. The angles of the teeth are named as if the teeth were
cubes, no matter how irregular or how much the angles may be rounded. In naming
the angles of the teeth, compounds of the names of the surfaces are used. There
are three sets of angles named. The first set is formed by the junction of the