This document discusses dental cutting instruments and their uses. It describes common excavators like hatchets, hoes, and spoons and how they are used to remove caries and shape tooth preparations. Chisels and other instruments like knives and files are also outlined. Grasping techniques like pen grasp and palm-and-thumb grasp are explained. Sharpening techniques on stones or mechanical sharpeners are covered, emphasizing maintaining a proper bevel angle and testing sharpness.

1. CUTING INSTRUMENT APPLICATIONS
•Used to cut hard & soft tissues of the mouth.
Mainly we have:
• Excavators.
•Chisels.
• Other cutting instruments.

2. EXCAVATORS
*Ordinary hatchets
*Hoes
*Angle formers
*Spoons

3. ORDINARY HATCHET(3-2-28)
*It has the cutting edge
directed in the same
plane as that of the
long axis of the handle
&is bibeveled.
* Used primarily on
anterior teeth for
preparing retentive
areas & sharpening
internal line angles.

4. HOE(4 ½ -1 ½ -22)
*cutting edge perpendicular to the
axis of the handle.
*used for planing tooth preparation
walls& forming line angles.
* Commonly used in classIII &
class V preparation for direct
gold restoration.

5. SPOON EXCAVATORS
 Bin angle spoon
(13-7-14)
 Triple angle spoon
(13-7-14)
* Spoon (15-7-14)

6.  spoon excavators are used for
>removing caries
>carving amalgam or direct wax pattern
*cutting edge of the spoon excavator are
>Discoid(circular)
>Cleoid(clawlike)
*shank may be bin angled or triple angled

7. CHISELS
1) Depending upon the shank angle& blade, it may be
>straight (12-7-0)
>Wedelstaedt(11 ½ -15-3)
>Bin angle(10-7-8)
2)Enamel hatchet
3)Gingival margin trimmer

8.  Straight chisel has a
shank & blade with the
bevel on one side.
 primary edge is
perpendicular to the
long axis of the handle.
 Bin-angle
&Wedelstaedt chisel
may have either a
distal bevel or a
mesial(reverse)bevel.

9. ENAMEL HATCHET(10-7-14)
 it is a chisel with larger
&heavier blade beveled
on only one side.
 cutting edge parallel
with the axis of handle.
 Use for cutting enamel
& comes as right or left
types.

10. GINGIVAL MARGIN TRIMMER
(12 ½-100-7-14)
 designed to produce
proper bevel on
gingival enamel
margins of proximo-
occlusal preparations.
 cutting edge is
angled(other than
perpendicular) to the
axis of the blade.
 comes as right and left
types.

11. OTHER CUTTING INSTRUMENTS
 Knife
 File
 Discoid-cleoid
instruments.

12. HAND INSTRUMENT TECHNIQUES
 Modified pen grasp
 Inverted pen grasp
 Palm-and-thumb &
 Modified palm-and-
thumb grasp

13. MODIFIED PEN GRASP
Similar to that of holding
a pen
Pads of thumb ,index ,&
middle fingers contact
the instrument, while
the tip of the fingers is
placed on a nearby
tooth of the same arch
as rest.
Palm generally is facing
away from the
operator.

14. INVERTED PEN GRASP
 Finger positions same
as that of the modified
pen grasp
 Hand is rotated
however, so that the
palm faces more
towards the operator.
 Used mostly for lingual
approach of the
anteriors

15. PALM-AND-THUMB GRASP
 Handle is placed in the
palm and grasped by
all the fingers, while
thumb is free and the
rest is provided by
supporting the tip of the
thumb on a nearby
tooth of the same arch
or on firm stable
structure.

16. MODIFIED PALM-AND-THUMB GRASP
 Handle of the
instrument is held by all
the fingers whose pads
press the handle
against the distal area
of the palm & the pad &
first joint of the thumb.
 This grip fosters control
against slipage.

17.  RESTS:- the closer the
rest areas are to the
operating area, the
more reliable the are.
 GUARDS:- are hand
instruments or other
items such as
interproximal wedges,
used to protect soft
tissue from contact with
sharp or abrassive
instruments.

18. SHARPENING HAND INSTRUMENTS
 Requires because
instruments with dull
cutting edge cause
*More pain
*prolong operating
time
*more difficult to
control
*reduce quality in
tooth preparation

19. STATIONARY SHARPENING STONES
(OILSTONES)
 Available in coarse ,
medium& fine grit.
 Commonly used stones
are:- arkansas stone,
silicon carbide, aluminium
oxide& diamond.
 Technique;
 Thin film of light oil should
be placed on working
surface.
 grasp the instruments with
modified pen grasp,
 Use light stroke
 Establish proper 45degree
angle of the bevel and the
cutting edge of the stone

20. MECHANICAL SHARPNERS
 example:- the Rx
Honing Machine.
 This instrument moves
a hone in a
reciprocating motion at
a slow speed, while the
instrument is held at
the appropriate
angulation
 Interchangable hones
of different shapes and
coarseness are
available

21. PRINCIPLES OF SHARPENING
 Sharpen instruments only after they have been
clean & sterilized
 Establish the proper bevel angle usually of
45degree
 Use light stroke or pressure to minimze frictional
heat.
 Use a rest or guide
 Remove as little metal as possible
 After sharpening, resterilize the instrument
 Keep sharpening stones clean.

22. SHARPNESS TEST
 Tested by lightly resting the cutting edge on a hard
plastic surface.
 If it digs in during sliding, the instrument is sharp.
 if it slides , the instrument is dull.