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should not now be difficult for those of you who have a fair ;
knowledge of dental nomenclature and have given close at-
tention to lectures up to this time, or will do so in the near
future. It will not be necessary in every case to include all
of these points, but most of them should be expressed.
Cavity description may give some of you trouble in its
formulation in the beginning, but a little study of it with
the view of its expression should remove the difficulty.
An example may assist you : Patient aged eighteen,
teeth well developed, bell crowned, interproximate spaces
broad, contacts narrow. No teeth lost ; free from calculus
gums and gingivae healthy ; teeth firm ; peridental membranes
apparently in good condition. Several proximate decays have
occurred, but conditions fairly favorable. Cavity in mesial
surface of upper first molar showing slight breakage of the
mesial marginal ridge of the occlusal surface, partially ex-
posing cavity to view. Examination with the explorer shows
that the decayed area involves the middle three-fifths of the
mesial surface, bucco-lingually, and the occlusal two-thirds
occluso-gingivalty. The excavation was begun with straight
chisel 15, by hand pressure, chipping away the enamel of the
mesial marginal ridge of the occlusal surface to the lingual
and to the buccal until the bucco-lingual breadth of the cavity
was exposed. The enamel was chipped away toward the
central portion of the occlusal surface until it was found
firmly supported by sound dentine. With enamel hatchets
15-8-12 the buccal wall and the lingual wall were cut away
to sound dentine. Finding now that the depth of the cavity,
mesio-distally, would admit the hatchet 20-9-12, this was
used to cut down the gingival wall to sound dentine.
The necks of the teeth having been carefully freed from
debris, the rubber dam was now applied to the tooth, includ-
ing, also, the first and second bicuspids, and secured upon
the molar with a suitable clamp. The tooth and interproxi-
mate space having been dried, careful examination showed
superficial injury to the enamel, both to the buccal and
lingual of the cavity as first roughly cut. Therefore, the
buccal wall was extended with the binangle chisel 20-9-6,
well out toward the buccal angle of the tooth where the
enamel margin would be kept clean. A similar extension
was made to the lingual with the enamel hatchet, and the

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