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DRAWINGS 121

two t}^ical forms depending on the shape of the occlusal
groove.

3. Cavity in central and distal fossae of 6, 7 and 8 (Figs.
129 and 130). If the oblique ridge
BUCCAL
is left very weak, unite the cavi-
ties. If _8_ has three cusps, the
typical form will appear as in Fig.
DISTAL MESIAL
131-
4. Cavity on the occlusal sur-
face of 6 (Fig. 132).
5. Cavity on the occlusal sur-

face of 7 (Fig. 133). On 8 the
LINGUAL
outline form will appear like that Fig. 126.—Outline form. Oc-
clusal cavity on the upper first
for 6 , or 7 , depending on the form
bicuspid.
of the tooth.
6. Mesial cavity on 1 (Fig. 131). The outline form for

proximal cavities in the six anterior teeth, upper or lower, is
about the same.
BUCCAL
BUCCAL

MESIAL
OlSTAL DISTAL
>/ MESIAL

LINGUAL LINGUAL
Fig. 127.—Outline form. Occlusal cavi- Fig. 128.—Outline form. Occlusal
ties on the lower first bicuspid. cavity in a lower second bicuspid with
three cusps.

Technic for Establishing the Outline Form.
(i) On Enlarged Plaster Teeth.— (a) With a pencil draw

the outline form, (b) With vulcanite chisels and scrapers
remove enough of the plaster to establish a definite cavity.