Page 63 - My FlipBook

SAWING AND FILING SECTIONS 3 1

on the labial surface ; then draw a straight line from this point

to the mesial and distal surfaces, which will then give the
extent of the curvature (Fig. 39).
(k) Bring all the cuttings down to proper measurement,
and do the finer carving with the file, scraper and small

chisels and excavators, representing the marginal and gingival
ridges, grooves, cervical line and all other points (Fig. 40).
(i) Finish with sandpaper of increasing fineness, and then
with pumice and whiting on the lathe (Fig. 41).
2. Bicuspid and Molar.—Practically the same directions
are followed. First mark the contact points and saw or trim

not quite to them. Repeat the same procedure for the bucco-
lingual diameter. Then measure for the length of the crown
on the buccal, lingual, mesial and distal sides, after which

outline with the pencil the proper contours and saw or file to
them, finally extending the cuttings the desired length and
shape. Then complete the surface markings, such as ridges,
grooves and cusps, as" well as the^cervical line, with the
scraper and chisels and excavators, completing the work with
sandpaper, pumice and whiting.

If desired and time permits, the teeth of the upper and lower jaw, right or left
side, may be carved and then mounted in occlusion on hard or soft rubber jaws.
If this is done, all the teeth should be modeled after a definite type, as sanguine,
bilious, nervous or lymphatic. They may then be later used for the technic exercises
in cavity preparation.

Sawing and Filing Sections

The object of cutting sections is to give the student
familiarity with the cutting consistence of natural tooth struc-
ture, to familiarize him with the thickness of enamel, dentin

and cementum, together with their relations to each other,
and to expose the pulp chamber and canals for purposes of
study.