10. .
SHAFT
Used as a handle , is straight without
variations in size.
It may be serrated to increase friction for
hand gripping.
11. SHANK
It connects the handle to the blade.
It is here where any angulation in the
instrument can be given.
12. BLADE
It is the functional end of the
instrument.It is connected to the handle
by the shank.
The blade ends in cutting edge.
13. CUTTING EDGE .
It is the working part of the
instrument . It is usually in
the form of a bevel with
different shapes
BLADE ANGLE.
It is defined as the angle
between the long axis of
the blade and long axis of
the shaft
CUTTING EDGE
ANGLE.
It is defined as angle
between the margin of the
cutting edge and the long
axis of the shaft.
14. INSTRUMENT NOMENCLATURE
G. V Black described dental instruments as
follows.
The order denotes the purpose of the
instrument ,eg excavator , scaler .
The suborder denotes the position or manner of
use of the instrument ,e.g. push or pull.
The class describes the form of the blade ,e.g.
hatchet, chisel.
The subclass denotes the angle or shape of the
shank.e.g straight- no angle
15. INSTRUMENT FORMULA
The width of the blade in
tenths of millimeters.
The primary cutting edge
angle formed between cutting
edge and central axis of shaft.
The length of the blade in
millimeters.
The blade angle in centigrade.
16. EXPLORING INSTRUMENTS
MOUTH MIRRORS
TYPES OF MIRROR SURFACES
1 a. front surface reflecting mirror
b. rear surface reflecting mirror
2. a. plane or flat surface
b. concave surface
3. a. one sided
b. two sided
18. EXPLORER
Diagnostic aid in evaluating condition of teeth especially
in pits and fissures
PARTS
Straight explorer
Shephered’s crrok or curved explorer
Interproximal explorer
19. TWEEZERS
They have angled tip and available in different sizes.
They are used to place and remove cotton rolls and
other small materials.
PERIODONTAL PROBES
They are used for measuring pocket depth.
20. INSTRUMENT DESIGN.
1. Direct cutting and lateral
cutting instruments.
2. Contrangling.
3. Right and left
instruments.
4. Single bevelled
instruments.
5. Bibevelled instrument.
6. Triple bevelled
instruments.
7. Circumferentially
bevelled instruments.
8. Single ended and
double ended
instruments.
21. A direct cutting instrument :
The force applied in the same plane as that of
the blade and handle ; it is called single planed
instrument.
Have 2 or more curves or angles in their shanks
,and in the same plane as the handle.
Used in direct or lateral cutting.
1.DIRECT CUTTING AND LATERAL
CUTTING INSTRUMENTS.
22. Lateral cutting instruments:
The force applied at a right angle to the
plane of blade and handle.
Are called double planed instruments
Have an angle or curve in a plane at a right
angle to that of handle.
Used in lateral cutting.
23. Have one or more angles
in shank placing the
working point within 3mm
from the axis of handle.
This principle of design is
called contrangling.
A short blade and small
blade angle requires only
bi angle- contrangling .
While longer blade and greater
blade angles requires triple angle
contrangling .
2.CONTRANGLING.
24. Direct instruments are made either right or
left by placing a bevel on one side of the
blade.
If the the cutting edge down and pointing
away from the operator and the bevel is
on the right side ,it will be’ right’
instrument.
If the bevel is on the left ,it will be a left
instrument.
These are all single planed instruments.
.
3 .RIGHT AND LEFT INSTRUMENTS.
25. SINGLE ENDED AND DOUBLE ENDED
INSTRUMENTS.
Double ended instruments incorporating the right and
left or the mesial and distal form of the instrument in
the same handle.
Single ended instrument have only one specific
function.
26. EXCAVATORS
THESE ARE DESIGNED FOR EXCAVATION REMOVAL OF CARIOUS DENTIN AND FOR THE
SHAPING OF THE INTERNAL PARTS OF CAVITIES.
HOE EXCAVATOR.
SPOON EXCAVATOR.
DISCOID EXCAVATOR.
CLEIOD EXCAVATOR.
HATCHET EXCAVATOR.
28. Used for cutting mesial and distal walls of
premolars and molars.
HOE EXCAVATOR.
29. DISCOID EXCAVATOR
These are disc like .
Have a blade which is circular in shape.
Cutting edge extending around the periphery except where it is
joined to the shank.
It is used for the same purpose and in the same manner as a spoon
excavator.
It is double –planed instrument right or left cutting movements.
30. It resembles a claw
,hence the name
“cleoid”.
It is essentially a spoon
excavator except the
blade comes to a point.
It is double –planed
instrument with lateral
cutting movements.
Used in carving
amalgam and
excavating decay.
CLEOID EXCAVATOR.
31. CHISEL
THESE ARE INTENDED FOR CUTTING ENAMEL. IT USUALLY BEVELLED ON ONE SIDE .
STRAIGHT CHISEL.
MONO ANGLE CHISELS.
BI ANGLE CHISELS.
TRIPLE ANGLE CHISELS.
32. STRAIGHT CHISELS.
Have a straight blade in line
with the handle and shank.
The cutting edge is on one side
only, with the bevel of the hand
running at a right angle to the
shaft.
They are single planed
instruments
with 5 possible cutting
movements.
33. ENAMEL
HATCHET.
The shank has one or more angles
or curves.
The blade is in same plane ,parallel
with the shaft.
Cutting edge is in the form of a
bevel parallel to the shaft; either
paired or may be bibevelled.
These are single planed
instruments with vertical, push,
pull, and either right or left lateral
cutting.
Smaller size for anterior teeth,
and larger size for posterior teeth
34. SPECIAL FORMS OF CHISELS
These designed to perform specific functions.
ENAMEL HATCHETS.
GINGIVAL MARGIN TRIMMERS.
ANGLE FORMERS.
WEDELSTEADT CHISELS.
OFFSET HATCHETS.
TRIANGULAR CHISELS.
HOE CHISELS.
HATCHETS OR OFFSET HATCHETS.
35. GINGIVAL MARGINAL TRIMMERS.
Similar to spoon excavators and
the cutting edge similar to single
bevelled hatchets.
2 types are;
1. Distal gingival margin
trimmers.
2. Mesial gingival margin
trimmers.
They are used for creating the
proper bevel of the gingival
floors and also for forming
sharp angles in internal parts
of cavity preparations.
They are also used in pull and
push motions.
36. RESTORATIVE INSTRUMENTS
CEMENT SPATULAS
Several types of spatulas are available in the market
differing in shape and size.
On the basis of size, cement spatula can be classified
into:
- large
- small
37. PLASTIC FILLING INSTRUMENT
These instruments have a small metal ball at the working
end. They are used to mix, carry and place cements.
CONDENSER
It is used to deliver the restoration to the tooth
preparation and for proper condensation
38. AMALGAM CARRIERS
To pack amalgam material in to the tooth preparation,
amalgam carriers are used.
They carry the freshly prepared restorative material in to
the tooth.
CARVERS
They are used to contour the restoration.
Sharp cutting edges present in carvers are used to
sharpen and form tooth anatomy from a restoration.
39. BURNISHERS
For final condensation of amalgam
Initial shaping of occlusal anatomy of amalgam
COMPOSITE RESIN INSTRUMENT
A wide range of double ended instruments are used
to transport and place resins
They are made up of plastic or titanium coating
40. ROTARY CUTTING INSTRUMENTS Those instruments which rotate on an axis to do the work
of abrading and cutting on tooth structure.
TYPES :
- Handpiece
- Bur
HANDPIECES
The first rotary instruments were drill or bur heads that
were twisted with the fingers for crude cutting of the tooth
tissue
41. TYPES OF HAND PIECE
Contra-angle hand piece
Head of handpiece is first angled away from
and then back towards the long axis of the
handle
a.Airoter contraangle handpiece-it gets power from
the compressed air supplied by the compressor. It
has high speed and low torque.
42. Micromotor handpiece
In straight handpiece long axis of the bur lies in
same plane as long axis of handpiece.
43. DENTAL BURS
It is a rotary cutting instrument which has bladed
cutting edge.
They are used to remove tooth structure either by
chipping or grinding.
44. CLASSIFICATION OF BURS
According to mode of
attachment
latch type
friction grip
According to their
composition
stainless steel
tungston carbide
combination
According to their
motion
right bur
left bur
According to the length
of their head
long
short
regular
45. According to their use
cutting burs
finishing burs
polishing burs
According to their
shape
round bur
inverted cone bur
pear-shaped
wheel shaped
tapering fissure
straight fissure
end cutting bur
46. BUR DESIGN
BUR BLADE
It is the projection on the bur head which forms a
cutting edge.it has two surfaces
rake face-surface of bur lade on the leading edge
clearance face-surface of bur blade on the trailing
edge
47. RAKE ANGLE -angle between rake face and radial
line
Positive rake angle-when rake face trails the
radial line.
Negative rake angle-when rake face is ahead of
radial line.
Zero rake angle-when rake face and radial line
coincide each other.
48. RADIAL LINE
It is the line connecting center of the bur and the
blade.
LAND
It is the plane surface immediately following the
cutting edge.
CLEARANCE ANGLE
This is the angle between the clearance face and the
work.
49. BLADE ANGLE
it is the angle between the rake face and the
clearance face.
CONCENTRICITY
it is a direct measurement of symmetry of the bur
head.
RUN-OUT
it measures the accuracy with which all the tip of
blades pass through a single point when bur is moving.
