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P. 457
;
INSTRUMENTS FOB CANAL TREATMENT. 455
Fig. 445. Fig. 446.
Dr. Donaldson's pulp-canal cleansers.
enlarge the canal, but will merely guide
the drill into a canal no wider than itself,
until it reaches tlie root-apex, through
which only the sharp point will pass, and
produce a sensation of pain that gives
notice of its protrusion yet, unless the
;
foramen is wider than the base of the
guide, the Gates drill will not cut
through the end of the root—a danger
that the improved drill is specially
designed to avoid. The reamers are
made with their thinnest part near the
junction of shaft and stem, so that
should fracture of the tool occur, a long l:
Dr. Donaldson's spring-
tempered nerve-bristles, piecc will be left protruding from the
tooth and may be readily withdrawn.
Using the series, one after the other, with care and judgment, even
a tortuous canal may be suitably enlarged ; but it should be kept in
mind that many roots are thin at their
apical portions, and their canals, if much P'lG. 447.
enlarged, may be cut through laterally
hence the advisability of employing usu-
ally the smaller sizes of drills, and always
the smallest first when the canal is narrow.
There is a diversity of opinion as to the
wisdom and propriety of using reamers of improved oates-Giidden nerve-
\ canal drill for engine work.
1
any kind in pulp canals. They are con-
demned in toto by some operators ; others advise their employment
in all cases.
INSTRUMENTS FOB CANAL TREATMENT. 455
Fig. 445. Fig. 446.
Dr. Donaldson's pulp-canal cleansers.
enlarge the canal, but will merely guide
the drill into a canal no wider than itself,
until it reaches tlie root-apex, through
which only the sharp point will pass, and
produce a sensation of pain that gives
notice of its protrusion yet, unless the
;
foramen is wider than the base of the
guide, the Gates drill will not cut
through the end of the root—a danger
that the improved drill is specially
designed to avoid. The reamers are
made with their thinnest part near the
junction of shaft and stem, so that
should fracture of the tool occur, a long l:
Dr. Donaldson's spring-
tempered nerve-bristles, piecc will be left protruding from the
tooth and may be readily withdrawn.
Using the series, one after the other, with care and judgment, even
a tortuous canal may be suitably enlarged ; but it should be kept in
mind that many roots are thin at their
apical portions, and their canals, if much P'lG. 447.
enlarged, may be cut through laterally
hence the advisability of employing usu-
ally the smaller sizes of drills, and always
the smallest first when the canal is narrow.
There is a diversity of opinion as to the
wisdom and propriety of using reamers of improved oates-Giidden nerve-
\ canal drill for engine work.
1
any kind in pulp canals. They are con-
demned in toto by some operators ; others advise their employment
in all cases.
