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P. 151
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FORMING CAVITIES. 147
cavities, there is considerable diversity of practice
under-cutting and grooving have been very com-
monly employed. Another method has been very
frequently adopted during the last three or four
years, namely, that of drilling little holes or pits into
the dentine at the most favorable points, these taking
different directions. This kind of retaining points is
much better calculated to answer the purpose, in
filling with crystal gold, or adhesive foil by Dr.
Arthur's method, than with the ordinary foil after
the old methods. When these perforations are made
at different inclinations, and then perfectly filled with
adhesive gold of any kind, the filling will certainly
be retained in place. For making these perforations,
a small square-edged drill is the proper instrument.
Such retaining points are seldom or never required
in crown cavities of the molars ; but in proximal
cavities they are frequently employed with great
advantage. In forming them, great care should be
exercised, lest the pulp-chamber is encroached upon
by the instrument. In almost all cases, the proper
point for forming them is in the cervical wall of the
cavity.
Another particular to which attention should be
given is the border of the orifice. It should always
be an object to secure an even, smooth, and strong
border to the orifice of the cavity. It is impossible
FORMING CAVITIES. 147
cavities, there is considerable diversity of practice
under-cutting and grooving have been very com-
monly employed. Another method has been very
frequently adopted during the last three or four
years, namely, that of drilling little holes or pits into
the dentine at the most favorable points, these taking
different directions. This kind of retaining points is
much better calculated to answer the purpose, in
filling with crystal gold, or adhesive foil by Dr.
Arthur's method, than with the ordinary foil after
the old methods. When these perforations are made
at different inclinations, and then perfectly filled with
adhesive gold of any kind, the filling will certainly
be retained in place. For making these perforations,
a small square-edged drill is the proper instrument.
Such retaining points are seldom or never required
in crown cavities of the molars ; but in proximal
cavities they are frequently employed with great
advantage. In forming them, great care should be
exercised, lest the pulp-chamber is encroached upon
by the instrument. In almost all cases, the proper
point for forming them is in the cervical wall of the
cavity.
Another particular to which attention should be
given is the border of the orifice. It should always
be an object to secure an even, smooth, and strong
border to the orifice of the cavity. It is impossible
