cutting instrument in dentistry

1. CUTTING INSTRUMENTS
ELIF ILGI SANCAK DDS, PHD
ASSISTANT PROFESSOR

2. PARTS OF HAND CUTTING INSTRUMENTS
• Each hand instrument is composed of three
parts (figs 6.1A and B):
1. HANDLE OR SHAFT
2. SHANK
3. BLADE OR NIB.
Figs 6.1A and B: Schematic representation of parts of a
hand instrument

3. HANDLE OR SHAFT
Handle is used to hold the instrument.
• It can be small, medium or large, smooth or serrated for better
grasping and developing pressure (figs 6.2A to C).
• On the handle, there are two numbers; one is the instrument
formula, which describes the dimensions and angulation of the
instrument, the other number is the manufacturer’s number which
is used for ordering purposes.
Figures 6.2A to C: Different
designs of instrument handle for
better grasping

4. SHANK
• Shank connects the handle to the blade.
• It tapers from the handle down to the blade and is normally smooth,
round or tapered.
• The shank may be straight or angled.
• Angulation of instrument is provided for access and stability.
• Closer the working point to the long axis of the handle, better will be
the control on it.
• For better control, the working point should preferably be within 3
mm of the center of the long axis of the handle (figs 6.3A and B).
Figures 6.3A and B: Balancing of
instrument (A) Working end of
instrument lies within 2–3 mm
to long axis of handle, this
provides balancing; (B) Working
end is away from long axis of
handle, does not provide

5. BLADE OR NIB
• Blade is working part of the instrument which has nib or cutting edge.
• It is connected to the handle by the shank.
• For noncutting instruments, the working part is termed the nib and is used to place, adapt and
condense the materials in the prepared tooth.
• Depending on the materials being used, the surface of the nib may be plain or serrated.
• For cutting instruments, working part is beveled to create the cutting edge.

6. INSTRUMENT FORMULA
� GV Black established an instrument formula for describing
dimensions of blade, nib or head of instrument and angles
present in shank of the instrument (fig. 6.5).
� Formula is usually printed on the handle consisting of a code of
three or four numbers separated by spaces.
� Formula uses metric system. For designating the angulation,
centigrades are used.
� Centigrades are based on a circle divided into 100 units rather
than 360 degrees circle which are normally used to describe
angles. For example, in a centigrade circle, right angle has 25.0
centigrades.
Figure 6.5: Schematic
representation of instrument
formula

7. EXAMPLE OF THREE-NUMBER FORMULA
An instrument having instrument formula
of 15-8-14 (figs 6.8a and b) indicates
following:
� 15 represents the width of the blade in
tenths of a mm, i.e. 1.5 mm
� 8 represents the length of the blade in
millimeters, i.e. 8 mm
� 14 represents the blade angle in
centigrades.
Figures 6.8A and B: Schematic
representation of three-number formula

8. EXPLORING INSTRUMENTS
Mouth Mirrors
 Mouth mirror is used as supplement to improve access to instrumentation (Figs 6.11A and B).
 It has handle, shank and a mirror attached to a round metal disk at one end.
A
B
Figures 6.11A and B: (A) Different sizes of
mouth mirrors; (B) Photograph showing
mouth mirror

9. USES
Direct vision
Indirect vision (fig. 6.13)
Retraction (figs 6.14a and b)
Transillumination.
Figure 6.13: Mirror used for indirect
vision of lingual surfaces of mandibular
anterior teeth
Figures 6.14A and B: (A) Mirror helps in retraction of cheek; (B) Tongue can be
A B

10. EXPLORER / PROBE
Explorer is commonly used as a diagnostic aid in evaluating
condition of teeth especially pits and fissures (figs 6.15A to
C).
PARTS
 Handle of explorer is straight which could be plain or
serrated shank of explorer is curved with one/more angle
 Working tip of explorer is pointed.
USES
 Examination of interproximal caries
 For assessing marginal fit of the restoration.
Figures 6.15A to C: Different types of
explorers (A) Interproximal; (B) Straight;
(C) Curved
A
B
C

11. TWEEZERS
 These have angled tip and are available in different sizes (figs
6.17A and B). They are used to place and remove cotton rolls and
other small materials to and from the mouth.
PROBES
 Though they almost look like straight explorers but they have
blunt end which is marked with graduations (fig. 6.18).
USES
 Mainly used for measuring pocket depth
 To determine dimensions of tooth preparation.
Figures 6.17A and B: (A) Tweezers;
(B) Diagrammatic representation of
tweezer
A
B
Figures 6.18 Schematic
representation of
periodontal probe with

12. HAND CUTTING INSTRUMENTS
• Instrument Families
• Chisels
– Straight chisel
– Monoangle chisel – binangle chisel
– Tripleangle chisel – wedelstaedt chisel.
• Enamel hatchet
• Gingival marginal trimmer.
• Excavators
– Hatchet
– Hoeexcavator
– Angleformer
– Spoonexcavator.
• Others
– Knives
– Files
– Discoid-cleoid. – offsethatchet – hoechisel.

13. CHISELS
• Chisels are used for cleaving, planing and lateral scraping. In other words, they are used to split
tooth enamel, to smooth preparation walls and to sharpen the preparations. Chisels are used
with a push motion.

14. HATCHET
• Any instrument where the cutting edge is parallel or close to
parallel to the plane of the instrument is called a hatchet.
Basically, a hatchet is the similar to an axe except that it is
much smaller (Figs 6.22A and B).
• Hatchet is a paired instrument in which blades makes 45 to
90° angle to the shank.
In paired right and left hatchets, blades are beveled on
opposite sides to form their cutting edges (Figs 6.23A and
B).
• Hatchets are used for cleaving enamel and planing the
dentinal walls so as to have sharp outline of the preparation.

15. EXCAVATORS
Spoon Excavator
• Spoon excavator is a modified hatchet.
• It is a double-ended instrument with a spoon, claw, or disk-shaped blade (Figs 6.30A
and B).
Spoon excavator is used to:
• Remove caries and debris in the scooping motion from the carious teeth.
• For carving amalgam restorations and wax patterns.
Knives
• Also known as finishing knives, gold knives or amalgam knives.
• They have thin knife like blade and are used for removing excess material and
contouring.
• Used in scrape-pull motion.
A
B
Figures 6.30A and B: Spoon excavators:
(i) Regular spoon shaped; (ii) Discoid spoon
shaped

16. RESTORATIVE INSTRUMENTS
CEMENT SPATULAS
• A great variety of restorative materials need to be mixed with a
spatula, over a paper block or a glass plate, before use. The
spatulas are available in different sizes and thickness, depending on
the application (Figs 6.32A and B).
• The large spatulas are used to mix large amounts of materials,
while the small ones are for reduced quantities, such as in the case
of protective lining materials. Small spatulas have also been used
to mix small quantities of resin cements. The thin spatulas are
more flexible than the thick ones, and the choice between one
over another depends on the material to be mixed (Figs 6.33A and
B):
Figures 6.32A and B: (A) Large
cement spatula; (B) Small cement
spatula
Figures 6.33A and B: Different
types of cement spatula (A)
Agate spatula; (B) Cement

17. PLASTIC FILLING INSTRUMENT
These instruments have a small metal ball at the working end.
They are double ended instruments.
• Two types are:
i. Flat end/nib with blunt edges on each end, one perpendicular to
other.
ii. One is flat end/nib and other end is round condenser nib.
• They are used to mix, carry and place cements (Figs 6.34 and
6.35).
• Plastic instrument is also used to check the convenience form of
tooth preparation.

18. Fig 6.36 a Many types of plastic filling instruments for sculpting composites; b instruments with silicon tips
(silicon brush – Micerium); c silicon sculpting instruments (Esthetics Plus, TDV); d brushes with different shapes
(on the left the Kolinsky fur and on the right synthetic fur – Kota)

19. CONDENSERS
• The condensers or pluggers are instruments used to condense and adapt the amalgam toward the
walls of a cavity preparation (figs 6.37 and 6.38).
• Their nibs are flat and generally circular in cross section, even though some models can also be rect-
angular- or diamond-shaped. There are basically three types of condensers, the ones developed by
black have a cylindrical nib, while the ones developed by hollenback have cone-shaped nibs. The
pluggers created by ward have inverted cone-shaped nibs
• The pressure of condensation is related to the force applied by the operator and to the diameter of
the nib. The small ones result in more pressure and are ideal to condense the material in places of
difficult access, such as retention areas. The large nibs are used to condense large amounts of
material on the occlusal surface.

20. Fig.38 Amalgam condensers. a Ward; b Black
a b
Figure 6.37: Photograph showing condensers

21. AMALGAM CARRIERS
• Amalgam carriers carry the freshly prepared amalgam
restorative material to the prepared tooth.
• A poorly packed amalgam carrier may result in amalgam
fall out before it is ejected into the prepared tooth.
• After restoration is completed, any remaining amalgam
alloy is expelled out from the carrier into the amalgam
well, otherwise carrier will no longer be serviceable if the
amalgam is allowed to harden in the carrier.
Fig 6.39 Amalgam carriers

22. CARVERS
• The carvers are used to shape amalgam restorations (Fig. 6.40). The blades must
be kept sharp to provide effectiveness.
• The use of each instrument depends on the site and type of anatomy to be
reproduced, besides individual preferences during the use.
Fig 6.40 Carvers

23. BURNISHER
• The burnisher is an instrument that has a dull nib with many shapes. It is used by rubbing the
nib on the surface of amalgam restorations, before and after carving, to improve condensation
of the material and create a smoother surface. Figure 6.41 shows examples of different
burnishers.
Fig 6.41 Amalgam burnishers (a egg shape; b
Bennett; c Hollenback No. 6; d Clev-Dent
burnisher)
Uses
o Final condensation of amalgam
o Initial shaping of occlusal anatomy of
amalgam
o Shaping of metal matrix bands
o Shaping of occlusal anatomy in posterior
resin composite before polymerization of
resin
o Burnishing margins of cast gold
restoration.

24. INSTRUMENT GRASPS
MODIFIED PEN GRASP
• Most commonly used grasp.
• Greatest delicacy of touch is provided by this grasp.
• Modified pen grasp is similar to the pen grasp except
the operator uses the pad of the middle finger on the
handle of the instrument rather than going under the
instrument (figs 6.42 and 6.43).
• Positioning of the fingers in this manner creates a
triangle of forces or tripod effect, which enhances
the instrument control.
• Most commonly used for mandibular teeth.
Figure 6.42: Modified pen grasp
Figures 6.43A and B: (A) Pen grasp; (B)
Modified pen grasp. There is difference in
angle formed by shaft of the instrument and
long axis of the forearm

25. • INVERTED PEN GRASP
• In inverted pen grasp, finger positions are the same as for the modified pen grasp except that
hand is rotated so that palm faces towards the operator (fig. 6.44).
• This grasp is most commonly used for preparing a tooth in the lingual aspect of maxillary
anterior and occlusal surface of maxillary posterior teeth (fig. 6.45).
Figure 6.45: Inverted pen grasp is
commonly used for preparing lingual
aspect of maxillary anterior teeth
Figure 6.44: Inverted pen grasp

26. PALM AND THUMB GRASP
• This grasp is same as for holding the knife for peeling the skin of an apple.
• Here, instrument is grasped very near to its working end so that thumb can be braced against
the teeth so as to provide control during instrument movements.
• This grasp has limited use only while operating on maxillary anterior teeth.
Palm and thumb grasp

27. • The finger rest helps to stabilize the hand and the instrument by providing a firm rest to the
hand during operative procedures. Finger rests may be intraoral or extraoral.
• The finger rest is achieved from tooth of the opposite side but the same arch or tooth from
opposite arch or just near to the working tooth. It may also be extraoral.
FINGER RESTS
Finger rests

28. MATRIX RETAINER
• The matrix retainers are instruments designed to hold a metallic strip, called matrix band, used
to give contour to restorations at the proximal surfaces.
Tofflemire Ivory
Automatrix
Walser
Sectional matrix

29. WEDGES
The wedges are pieces of wood, plastic, or elastic material introduced into the interproximal
space, between the matrix and the proximal surface of the adjacent tooth, over the interdental
gingival papilla, to guarantee the correct restoration of the proximal surface. Among the functions
of the wedges, the following ones must be highlighted:
Helps to stabilize the matrix band
Aids on the restoration of the adequate contour of the lost
surface, because it approaches the matrix to the remaining
tooth structure on the cervical region of the proximal surface
Prevent the extrusion of the restorative material in the
gingival margin of the preparation
Aids to retract the rubber dam and the interdental gin- gival
papilla
Promotes separation between the adjacent teeth to com-
pensate the thickness of the matrix band

30. • When made of a rigid material, it must have the exact shape of the interproximal space as it can
be observed in fig. 6.46a. The interproximal space has a triangular shape, with the apex toward
the contact point and the base toward the gingival tissue. Therefore, the wedge must also
present a triangular cross section, being named anatomic wedges (Fig. 6.46b). The wedges are
inserted through the larger embrasure, once they have a convergence toward the tip.
Fig 6.46 Correct shape of the anatomic wooden wedge. a Shape of the interproximal space –
asterisk; b shape of the anatomic wedge
a b

31. ISOLATION OF THE OPERATING FIELD
 ISOLATION USING RUBBER DAM
 Rubber Dam
 Rubber Dam Frame
 Punch
 Clamps
 Forseps
 Other Retainers
 USING COTTON ROLLS COMBINED WITH SUCTION
• Saliva Ejector And High-volume Evacuators
• Cotton Rolls And Absorbent Pads
• Cheek And Tongue Retractors
• Light-cured Gingival Barriers
• Gingival Retraction Cords

32. ISOLATION USING RUBBER DAM
The use of a rubber dam was introduced by Sanford Christie Barnum to completely eliminate
fluids from the operating field. If well performed, the moisture control with its use is simple and
effective; hence it is highly recommended to maintain the teeth dry during restorative
procedures.
Further important advantages are obtained when isolating the operating field by using a rubber
dam: this ensures (1) retraction and protection of the patient’s soft tissues, (2) protection of the
patient’s respiratory and digestive tracts, and (3) improvement of access to visualization of the
operating field, thus allowing the dentist to concentrate on the treatment to be performed.
Gilmore HW, Lund MR, Bales CD, Vernetti S, editors. The operating field. Operative dentistry. 3rd ed. St. Louis: CV Mosby Company; 1977. p. 100–16.
SummittJB.Fieldisolation.In:SummittJB,RobbinsJW,SchwarzRS, editors. Fundamentals of operative dentistry. Illinois: Quintessence Books; 1996. p. 109–39.

33. • The use of rubber dam is also important during excavation of deep carious tissue, as it prevents
the contamination of the pulp from microorganisms present in the oral fluids, specially in the
case of an accidental pulp exposure during excavation. During the removal of amalgam res-
torations, the use of a rubber dam prevents the patient from swallowing amalgam residues.

34. RUBBER DAM
The rubber dam isolates the operating field from the oral cavity. It is
often fabricated with natural latex and is available in several colors.
Latex-free sheets made of silicone or nitrile rubber are also available
and are indicated for patients allergic to latex. The colors that
contrast with the teeth are preferred because they improve the
visualization of the preparations’ and restorations’ details. The blue
color is generally chosen: it is the complementary color to the yellow
of the teeth, increases the perception of contrast, and is a relaxing
color to the vision.
Rubber dams are available generally as 13 cm × 13 cm sheets with
various thicknesses (thin, medium, thick, and extra thick).
Besek M. Optidam, the new dimensional rubber dam. Available from: http://www.kerrhawe.com/products/documents/Article_ Besek_en.pdf.
Rubber dam sheets with
different colors

35. RUBBER DAM FRAME
The rubber dam frame is used to keep the borders of the rubber sheet in position. The rubber
sheet must be stretched and fixed on the lateral pins of the frame.
Rubber dam frames are made of metal or plastic, the latter does not interfere on the uptake of
radiographic images during the operative procedures.
Young frames. a Plastic; b metallic Ostby frames. a Plastic; b metallic

36. PUNCH
The punch forceps is used to perforate the rubber sheet in the positions where the teeth to be
isolated shall fit. The ainsworth punch is commonly used: it has a plunger with a sharp end and a
rotating disk-shape metal table with several holes. These perforating holes have different
diameters to better fit the teeth.
In order to perforate the rubber sheet, the plunger should be placed over the pre-marked
positions and pressed firmly.
Punch forceps.

37. Detail of the perforating holes in the rotating
metal table on the Ainsworth punch and their
corresponding group of teeth. The largest
hole is used to make perforations for anchor
molars
Punching the rubber dam

38. CLAMPS
Clamps are used to secure the rubber sheet in place
and are generally made of a flexible metal. The
clamps should be placed on the tooth that is more
distal on the arch to the tooth in which the treatment
is to be performed, particularly when isolating
posterior teeth.
Clamps are available in different sizes and specifically
adapt to each group of teeth.
Some clamps have wings that allow attaching the
clamp in the rubber dam, while others are wingless.
Bow
Jaw
Wing
Prong
Hole for
forceps
Rectangular hole

40. FORCEPS
• The clamp holding forceps is used to securely position the clamp on the tooth.
Clamp forceps. a Palmer; b Brewer; c Ivory
a b c

41. USING COTTON ROLLS COMBINED WITH SUCTION
• The use of cotton rolls combined with suction aims to control the moisture of the operating field
and displace the surrounding soft tissues around the teeth, such as the lips, cheeks, and tongue.
It is difficult to reach complete moisture control during the operative procedures, and because
this technique does not hinder the involuntary movement of the soft tissues, it must be used
with caution, during short periods of time and preferably in four-handed work
• Although the use of cotton rolls can be relatively effective in controlling the moisture, it does
not reduce the risks of contaminations and accidents.

42. The use of cotton rolls combined with suction in operative dentistry are indicated in the following
situations:
• When rubber dam isolation is impossible or impairs the aesthetic evaluation of the operating field
• In patients with nasal obstruction or mouth breathing
• When rubber dam isolation has failed
• In teeth that are partially erupted or misaligned and placing the clamp or other retainer is not possible
• In patients who are allergic to latex, if latex-free sheets are not available
• For topical fluoride application
• In cases of temporary restorations
• For direct veneers or large restorations on anterior teeth. Here, the use of cotton rolls and suction allows a better overview of the operating field
and improved visualization of the relationship between the teeth and the gingival level
• For multiple cervical lesions. here several teeth can be restored at once, while the rubber dam limits restoring two teeth at a time

43. SALIVA EJECTOR AND HIGH-VOLUME EVACUATORS
• Saliva ejectors are devices used to remove saliva and water
that comes from the high-speed handpiece. Saliva ejectors
are usually made in soft plastic not to hurt the soft tissues.
Disposable saliva ejectors that have a flexible metallic rod
are preferred, as they can be curved and adapted in several
places of the oral cavity.
• HVE are very useful when removing amalgam restorations,
thus minimizing the amount of amalgam residues to be
swallowed by the patient.
Examples of disposable saliva ejectors for
regular and more delicate to the surrounding
soft tissues; the one on the right of high-
suction evacuation; the transparent tubes can
be curved for the image also retracts the
tongue (ex. Sweflex saliva ejector) adaptation
in the oral cavity.

44. COTTON ROLLS AND ABSORBENT PADS
• The cotton rolls must be highly absorbent of saliva. Cotton rolls must always be used together
with the saliva ejectors and shall be carefully replaced when they become saturated.
• There are also absorbent rolls made of paper and to be adhered to the mucosa on the exits of
the parotid glands. Some pads have a reflexive external side covered by a layer of non-woven
fabric, with an identical shape as the cotton rolls.
Cotton rolls Saliva absorbing pads

45. CHEEK AND TONGUE RETRACTORS
• The cheek retractor
protects cheeks and lips
while increasing the
visual field.

46. • Biting blocks made of silicone can be used
to keep the mouth open in patients with
difficulties or opening limitations. The
biting blocks have multiple slots along the
lateral surfaces to stabilize on the occlusal
surfaces of the teeth. The biting blocks
must be inserted between antagonist
teeth on the opposite hemiarch to the one
that will receive treatment: the narrower
edge facing the more distal tooth. The
more posterior the biting block is placed,
the more the mouth will open anteriorly.

47. LIGHT-CURED GINGIVAL BARRIERS
• The light-cured resin-based gingival barriers are
flowable resins with pigments, which are used to
protect the gingival tissues. Even after light-curing,
these resins still show certain flexibility, which
makes their removal easy. The light-cured gingival
barriers can be useful to protect the gingiva from
in-office bleaching agents, but they can be also
used to correct small defects in the rubber dam or
in combination with rubber dam in modified
applications.

48. GINGIVAL RETRACTION CORDS
• Flexible cords are inserted into the gingival crevice to retract the gingiva, improve the
visualization and access to gingival margins during tooth preparation and restoration, as well as
control gingival fluid or bleeding during the restorative procedure.