SlideShare verwendet Cookies, um die Funktionalität und Leistungsfähigkeit der Webseite zu verbessern und Ihnen relevante Werbung bereitzustellen. Wenn Sie diese Webseite weiter besuchen, erklären Sie sich mit der Verwendung von Cookies auf dieser Seite einverstanden. Lesen Sie bitte unsere Nutzervereinbarung und die Datenschutzrichtlinie.
SlideShare verwendet Cookies, um die Funktionalität und Leistungsfähigkeit der Webseite zu verbessern und Ihnen relevante Werbung bereitzustellen. Wenn Sie diese Webseite weiter besuchen, erklären Sie sich mit der Verwendung von Cookies auf dieser Seite einverstanden. Lesen Sie bitte unsere unsere Datenschutzrichtlinie und die Nutzervereinbarung.
Operative instruments in Conservative Dentistry & Endodontics
Dr. Ashok Ayer
Department of Conservative Dentistry and Endodontics
College of Dental Surgery
B. P. Koirala Institute of Health Sciences, Dharan, Nepal
Nomenclature & numbering of hand instruments
1. Cutting instruments/ excavators
Designs of some early hand instruments
1728 – Pierre Fauchard invented the bow drill
1891 – Edward C Acheson –produced carborundum tools
1935 – W H Drendes - Diamond cutting instruments
Remains bright under most conditions
Loses keen edge during use much more
Chromium: corrosion resistance
INSERTS OR BLADES TO PROVIDE MORE
DURABLE CUTTING EDGES (BRITTLE).
THEY MAY BE SOLDERED TO STEEL
SOME INSTRUMENTS ARE MADE WITH
CARBIDE TO PROVIDE MORE DURABLE
OTHER ALLOYS OF NICKEL, COBALT, OR
CHROMIUM ARE USED IN THE
MANUFACTURE OF HAND INSTRUMENTS.
THEY ARE RESTRICTED TO INSTRUMENTS OTHER THAN
THOSE FOR CUTTING TOOTH STRUCTURE
Hardening and Tempering Heat
Heat treatment Furnace
The hardening heat treatment hardens the
alloy, but it also makes it brittle, especially
when the carbon content is high.
Tempering heat treatment relieves strains and
Classification of Instruments:- by
PURPOSE OF THE INSTRUMENT
E.G. EXCAVATOR, SCALER
MANNER OF USE
E.G. PUSH, PULL
FORM OF BLADE
E.G. HATCHET, CHISEL
NUMBER OF ANGLES IN THE SHANK: MONOANGLE, BIANGLE,
E.G. BIANGLED HATCHET EXCAVATOR,
According to G. V. Black
Working part of the instrument
Usually in the form of a bevel (acute angle) that
cuts into the tooth structure.
On non cutting instruments e.g. condensers the
part corresponding to the blade is called the nib or
Connect the handle to the working end of the instrument.
Normally smooth, round and tapered.
Mon-angle, bin-angle, triple angle
Balance is accomplished by designing the angle of the shank so
that the cutting edge of the blade must not be off axis by more
than 1-2 mm (Sturdevant’s)/2-3 mm (Summitt)
Balance allows for the concentration of force onto
the blade without causing rotation of the
Instruments with long blades may required two or
three angles in the shank to bring the cutting edge
near to the long axis of the handle
Such shanks are termed contra angled.
Serrated for better gripping and control of the
a. Standard Stainless steel handle: Diameter 6.4 mm
b. Padded handles: Diameter 8mm approx.
c. Larger diameter handles: 9.5 mm
Less likely to develop carpal tunnel syndrome
Occupy more space in instrument tray
Handles are in conjunction with the shank
or it may be separable.
Separate type is known as cone-socket
handle and allows for replacement of several
working ends e.g. mirrors and condensers.
Describing the dimensions and angle of the working end.
Three number formula
Four number formula:
Cutting edge is not perpendicular to the long axis of the
Gingival marginal trimmer
Most hand cutting instruments have on the end of the
blade a single bevel that forms the primary cutting edge.
Additional two secondary cutting edges that extend from
the primary cutting edge for the length of the blade.
Allows cutting in 3 directions; facial and lingual walls of
the proximal cavity
Bibeveled instrument have two bevels that form
the cutting edge;
e.g. hatched excavator
Single beveled instrument such as spoon
excavator and gingival margin trimmer are
used with lateral cutting movement.
Enamel hatchet also as a single beveled instrument
used with direct cutting motion, a planning or
lateral cutting designated for right (R) and left (L) to
the instrument formula.
The cutting edge is perpendicular to
the axis of the handle
e.g. binangle chisel.
Instrument with slight blade curvature
Removal of caries and
refinement of the
internal parts of the
Used primarily for cutting
It has the cutting edge of the blade directed
In the same plane as that of the long axis of the handle
Used primarily on anterior teeth for
Preparing retentive areas and
Sharpening internal line angles, particularly in
preparations for direct gold restorations .
Primary cutting edge of the blade perpendicular
to the axis of the handle
Planing tooth preparation walls and forming line
It is commonly used in Classes III and V
preparations for direct gold restorations.
Hoes with longer and heavier blades, with the
For use on enamel or posterior teeth.
The blade angle of the hoe: > 12.5 centigrades
The blade angle of chisel: ≤ 12.5 centigrades
It is mon-angled and has the primary cutting edge
at an angle (other than 90 degrees) to the blade.
It is available in pairs (right and left )
Used primarily for sharpening line and point angles
and creating retentive features in dentin in
preparation for gold restorations
Also may be used in placing a bevel on enamel
Its blades are slightly curved, the shanks may be bin-angled
or triple-angled to facilitate accessibility.
The cutting edges are
The cutting edges are
Left cutting and right cutting
Used mainly for removal of caries and refinement of
internal opening in a cavity preparation
The straight chisel has a straight shank and blade,
with the bevel on only one side.
Its primary edge is perpendicular to the axis of
The shank and blade of the chisel also may be
slightly curved (Wedelstaedt design)
Force used with chisels : straight thrust
The bin-angle and Wedelstaedt chisels:
Primary cutting edges in a plane perpendicular to the
axis of the handle.
Distal bevel or a mesial (reverse) bevel.
Used for cleaving undermined enamel and for shaping
Instrument with three cutting motion: vertical, right and
The blade with a distal bevel is designed to plane a
wall that faces the blade's inside surface
The blade with a mesial bevel is designed to
plane a wall that faces the blade's outside surface
It is a chisel similar in design to the ordinary hatchet
excavator except that the blade is larger, heavier, and is
beveled on only one side
Right or Left cutting ends of the double- ended hatchet.
Gingival margin trimmer
Blade is curved
Bevel for cutting edge: outside of the curve
Face of instrument: inside of the curve
Beveling of the gingival margins of proximo-
Beveling of the axio-pulpal line angle
Performing a gingival lock (reverse bevel), placed
on the gingival seat
Usage of hand cutting instruments
Long axis of blade directed between 45 & 90
degree to the surface being planed or scraped
Vertical or chopping strokes:
Hoe: beveled end or distal bevel
Hoe: contrabeveled end or mesial bevel.
The cutting edge of the hand instrument should
always be kept sharp as
Dull instruments may cause:
1. Loss of control.
2. More pain.
3. Prolonged time for the operative procedure.
4. Reduce the quality and precision of tooth
Stationary sharpening stone e.g. Arkansas
stone, silicon carbide.
Mechanical sharpener; moves at low speed while
the instrument is held at the opposite angle and
supported by a rest i.e. easier and less time
E.g. Rx Honing Machine
Principles of Sharpening
Sharpen instruments only after they have been cleaned
Establish the proper bevel angle (usually 45 degree)
and the desired angle of the cutting edge to the blade.
Use light stroke pressure
Use a rest or guide whenever possible.
Remove as little metal as possible
Non cutting Instruments
Probe or explorer
Most common sizes used are the No. 4 (⅞ inch diameter)
and No. 5. (15/16 inch diameter)
No. 2 (5/8 inch diameter): when working on posterior teeth
with a rubber dam.
For clarity, reflective surface on the external surface of the
glass: Front surface mirror.
Uses for the mouth mirror. A, Indirect vision. B, Light reflection.
C, Retraction. D, Tissue protection.
To feel tooth surface for irregularities
To determine the hardness of exposed dentin
1. Shepherd’s hook: No. 23
2. Cowhorn explorer: No. 2
3. No. 17: back action
Tweezer/ cotton forceps:
Cotton forceps are used for picking up small items,
Plastic filling Instruments
To carry and shape tooth colored restorative material:
Composite resin and glass ionomer
For placing of base and lining material
Hard plastic or metal.
Composite placement instrument
Designed specifically for the placement of composite
Titanium nitride layer on instruments
Hand instruments with a blade or nib used to contour the
surface of filling material in their plastic state, waxes,
models and patterns.
Hollenback carver (knifed edged- elongated- bibevelled)
Diamond (Frahm’s) carver : Bibevelled cutedge.
Ward’s ‘C’ carver
Burnishing of the amalgam on the margins of the cavity,
Shaping metal matrix band to have more desirable contours for
To bend cast gold restoration (inlay or onlay) near the margin of
the prepared cavity to narrow the gap between gold and the
Used with etching and bonding procedures associated
with composite resins.
Used for cutting dental dam material, retraction cord,
and stainless steel crowns.
Crown and bridge scissors
Hold certain liquid dental materials during a procedure.
Also referred to as 110 pliers. Useful for holding items, for
carrying cotton products to and from the oral cavity,
removing the matrix band, and placing and removing the
Interproximal wedges to protect soft tissues from contact
with sharp rotary cutting instruments.
There are four grasps used with the hand
Palm and thumb.
Modified palm and thumb.
M o d i f i e d p e n g r a s p
pen grasp Modified pen grasp
Inverted pen grasp
If the hand is rotated so that the palm faces more toward
Used in the lingual and labial surfaces of anterior teeth.
inverted pen grasp
Palm and thumb grasp
The handle of the instrument is placed on the palm of the
hand and grasped by all the fingers while the thumb is free of
the instrument and rest on the nearby tooth of the same arch.
Preparing incisal retention in a class III preparation on a
Palm and thumb grasp
The same as in palm and thumb grasp but the
thumb is rested on the tooth being prepared.
Used in the upper arch.
SURFACE FEET PER UNIT TIME OF CONTACT THAT THE TOOL
HAS WITH THE WORK TO BE CUT OR REVOLUTIONS PER
ACCORDING TO MARZOUK:
1. ULTRA LOW SPEED: 300-3000 RPM
2. LOW SPEED: 3000-6000 RPM
3. MEDIUM HIGH SPEED 20,000-45,000 RPM
4. HIGH SPEED 45,000-1,00,000 RPM
5. ULTRA HIGH SPEED > 1,00,000 RPM
According to Charbenau:
1. Conventional or low speed: below 10,000 RPM
2. Increased or high speed: 10,000-1,50,000 RPM
3. Ultraspeed: above 1,50,000 RPM
According to Sturdevant:
1. Low or slow speeds: below 12,000 RPM
2. Medium/Intermediate speeds: 12,000 to 2,00,000
3. High/ Ultrahigh speeds: above 2,00,000 RPM
Low speed: 2-5 pounds of force
High speed: 1 pound of force
Ultra high speed: 1-4 ounces of force
Directly proportional to the Pressure, RPM, and
area of tooth in contact
113˚ F : Pulpitis & pulp necrosis.
130˚ F : Permanent damage of pulps.
Brown et al: Temperature of dentin at a distance of
0.5 mm from a high speed bur cutting dry to be
Even in non vital teeth, dry cutting at high speed
should be avoided, since the thermal stresses will
cause microfractures in the enamel. This could
contribute to marginal failure of the restoration.
Higher water velocity.
Clean head system
Greater flow of water coolant is required to prevent
clogging when diamonds are used under increased
42 psi is the optimal air pressure to achieve peak
EQUIPMENT USED & THE SPEED OF ROTATION
EXCESSIVE VIBRATION: ANNOYANCE TO THE PATIENT,
OPERATOR FATIGUE AND RAPID WEAR OF INSTRUMENTS.
ABILITY OF THE HAND PIECE TO WITHSTAND LATERAL
PRESSURE ON THE REVOLVING TOOL WITHOUT DECREASING
ITS SPEED OR REDUCING ITS CUTTING EFFICIENCY.
Occurs in the moving parts of the hand piece especially the
Friction is reduced by equipping the hand piece with ball
bearings, needle bearings, glass and resin bearings.
Ceramic Ball Bearings:
40% lighter and 3 times harder than conventional
bearings, they offer an extended turbine life, reduced
operation noise, and less vibration.
Two basic types of handpieces, the straight handpiece
and contra angle handpiece.
The straight is used more frequently for laboratory
work, while contra angle used in the oral cavity.
High speed techniques are generally preferred for
cutting enamel and dentin.
Penetration through enamel and extension of the
cavities outline are more efficient at high speed.
Small diameter burs should be used in the high
High speed generates considerable heat during
cutting, even with small diameter burs and should
be used with water coolant and high efficiency
This model is the choice for limited access or
when treating children.
Rear-facing exhaust vents direct air flow away
from the surgical site for patient protection
Zero Suck Back Technology
Prevents the intake of aerosol and other
particles when it is stopped.
Drive air flows into an Anti Suck Back
Diffuser (ASBD) within the capsule.
Air in the ASBD is pressurized through
centrifugal force created by the
Through the centrifugal force and
rotation of the impeller, air continues
to flow into the ASBD and remains
pressurized even after drive air is
The pressurized air in the ASBD is
released to the outside at the
bottom of the head
Straight in appearance.
Standard length and “short.”
Speed ranges from 10,000 to 30,000 rotations
per minute (rpm).
Operates the rotary instrument in either a
forward or backward movement.
Uses of the low-speed handpiece
Removal of soft decay and fine finishing of a
Finishing and polishing of restorations.
Coronal polishing and removal of stains.
Trimming and contouring temporary crowns.
Trimming and relining of removable partials and
Trimming and contouring of orthodontic
Straight attachment receives a long-shank laboratory
bur, the contra-angle attachment, and the prophy
Contra-angle attachment receives latch type rotary
instruments and mandrel.
Used during polishing procedures to hold the
prophy cup and bristle brush.
Plastic disposable “prophy” angle
Metal “prophy” angle
Uses of the high-speed handpiece
Removes an old or faulty restoration.
Reduces the crown portion of the tooth for the
preparation of a crown or bridge.
Prepares the outline and retention grooves for a new
Finishes or polishes a restoration.
Sections a tooth during a surgery.
Attached to the dental unit.
Powered by electricity.
Attachments are similar in appearance to scaling
Delivers a pulsating spray of water.
Uses of the ultrasonic handpiece
Removes bonding materials from a tooth surface
after orthodontic appliances are removed.
Removes cement after orthodontic bands are
Uses a laser light beam instead of rotary
The laser is conducted through a fiber-optic cable.
Resembles a standard handpiece.
Maintains a water-coolant system.
Maintains an air-coolant system
Cauterizes soft tissue.
Vaporizes decayed tooth structure.
Patient usually does not require anesthesia.
Proceed with procedure faster.
Cannot be used on teeth with existing restorations.
Small version of a sandblaster.
Compressed air at pressure of 7 to 11 atm (40
to 140 psi)
Produces a high-pressure delivery of aluminum
oxide particles (of 20 to 50 pm) through a small
Prepares teeth for sealants.
Removes external stains.
Class I through class VI preparations.
Prepares a tooth surface for the cementation of a cast
restoration, such as a crown or veneer.
More effective on hard normal dentine than soft
dentine affected dentine
When using composite, the air abrasion doesn’t
provide the micromechanical roughness needs for
retention thus needs acid-etchant.
Loss of tactile sensation.
Possible iatrogenic damage especially on the
cementum and root dentine.
Can induce asthma –> thus needs high volume suction
Can’t remove amalgam restoration.
Can’t perform massive reduction for crown.
Operates at speeds up to 20,000 rpm.
Uses laboratory burs.
Provides greater torque than handpieces used
According to composition:
1. Steel burs
2. Tungsten Carbide burs
According to mode of attachment to handpiece
1. Latch type
2. Friction grip type
According to handpiece they are designed for;
Rotary instruments consist of three parts :
2- neck (shaft)
head shaft Shank
Long shank – used for straight
hand piece (low speed)
Short latch shank – used for contra-angle (low speed)
Friction grip shank - used for high speed hand piece
A group of instruments that can turn on an axis with different
speed of rotation to perform different types of work.
The characteristics of this work are either cutting , abrasive,
finishing or polishing.
Steel burs cut human dentin at low speeds, but dulls rapidly at
higher speeds or when cutting enamel
Steel necks bends easily causing vibration
Burs possess blades that shear (cut) tooth
They are used for making precise
intracoronal preparation features such as
placing groove, and boxes.
Used for smoothing surface in enamel and
They are not used for bulk reduction
because to producing undulations on the
Initial entry into the tooth
Extension of the preparation
Retentive features and caries removal
Inverted cone bur
Undercuts in the tooth preparation
Pear shaped bur
Tooth preparation for amalgam, gold foil.
Straight fissure bur
Tooth preparation for amalgam
Tapered fissure bur
Tooth preparation for indirect restorations.
Its used for highly smoothing of prepared surfaces of tooth
Because of its blades in a diagonal to the instrument shaft
Its have a torpedo shape
Twelve-fluted carbide bur
Plain fissure bur
Its tapered and cylinder shape its used for placing
groove and boxes and they also used for finishing of
Bur numbering systems
In the united states the burs have been traditionally
described in term of arbitrary i.e. numerical code
eg, 2 =1 mm diameter round bur,
34 = 0.8mm inverted,
57 = 1mm diameter straight fissure
Number 500 is added to indicate cross cutting
Number 900 is added to indicate end-cutting only
So no. 57 ,557 and 957 are all had the same head size
Iso system(international standard organization)
FDI (Federation dentaire internationale)
Usually tend to use head shape name and size
(in tenth of a millimeter)
Eg. Round 010 = 1mm diameter
Straight fissure plain 010 = 1mm diameter
Inverted cone 008=0.8mm diameter
Bur head design:
The number of blades on a bur is always even
Number of blades on an excavating bur may vary from 6 to
8 t0 10.
Finishing bur: 12 to 40 blades
Measurement of the symmetry of the bur head.
Test measuring the accuracy with which all blade tips
pass through a single point when the instrument is
Average value of clinically acceptable run-out is about
Is the primary cause of vibration
Angle that the face of the bur tooth makes with the
Radial rake angle: radial line & the tooth face coincide.
Negative rake angle: blade face is leading the radial line
Increases the life expectancy of the bur & provides for the most effective
performance in low and high speed ranges.
Positive rake angle:
Produce acute edge angle
In the range of 90˚ to provide strength to the blade &
longevity of cutting efficiency of the bur.
Land: plane surface immediately following the cutting edge.
Flute/ Chip space:
Space between successive bur teeth or the blades of the bur.
Provides an exit for removal of the fractured matter and
creates a clearance angle.
Angle between the back of the blade and the tooth surface.
If a land is present on the bur:
1. Primary clearance angle: the angle the land will make with work.
2. Secondary clearance angle: the angle between the back of the bur
tooth and work.
3. Radial clearance angle: is formed when the back surface of the bur
tooth is curved.
Provides clearance between the work & the cutting edge to prevent
the tooth back from rubbing on the work.
Head consists of small angular particles of hard substance
embedded in a soft binder (ceramic, metal, shellac,
Other abrasives –Silicon carbide (carborundum),
aluminium oxide, garnet, quartz, pumice, cuttlebone.
Deposited by Electroplating, sintering or microbrazing.
These are made from diamond chips bonded to blanks
(heads). Diamonds used for grinding enamel and
Diamond burs may divided according to :
1- coarseness ( medium grit - fine grit )
Diamond particle size:
1) Coarse: 125~150 um
2) Medium: 88~125 um
3) Fine: 60~74 um
4) Very fine:38~44 um
Diamond instruments consists of three parts:
A metal blank,
The powdered diamond abrasive
A metallic bonding material that holds the
diamond powder onto the blank
Extra- fine: 20-30µ
TF: Taper flat end; TR: Taper round end; TC: Taper conical
end; FO: Flame Ogival end; SF: Straight flat end; SO:
Straight Ogival end; BR: Ball round; WR: wheel round edge;
Moulded abrasive instrument –
Manufactured by pressing a uniform mixture of abrasive
and matrix around roughened end of shank,
Points and stones; finishing & polishing
Coated abrasive instrument –
Disks that have a thin layer of abrasive cemented to a
surface contouring, finishing
SmartPrep Instruments (Smart Bur, Polymer Bur)
Medical polymer that has the ability to remove decayed dentine
while keeping the healthy dentin.
Its hardness is less than healthy dentine while harder than the
Ability to self-limit(selectively)
It will only cut what is carious and if it’s in contact with
healthy dentin the bur will only wear away (when extensive
force isn’t used).
Minimal to none disease transfer (because its single
No need for Local Anesthesia.
For Students to start with first clinical cases.
Single-patient-use = Expensive.
Technique sensitive ( too much pressure and you will cut
the healthy dentine)
The bur breaks down when it touches enamel.
It can sometimes leave large amounts of decayed tissue
(use caries dye to locate the left amount.
Access should be done by a different type of bur that can
penetrate the enamel.
Brittle fracture: crack production, by tensile loading.
High speed cutting, especially of enamel
Ductile fracture: plastic deformation, by shear.
Low speed cutting.
Diamonds are most efficient when used to cut
brittle materials, are superior to burs for removal of
the dental enamel.
Burs are generally preferred for cutting ductile
materials such as dentin.
Use of contra-angled handpiece, air-water spray
for cooling, high operating speed (above 200,000
rpm), light pressure.
Carbide burs are better for end- cutting, produce
lower heat, and have more blade edges per diameter
Diamonds are more effective than burs for both
intracoronal & extracoronal tooth preparations,
CHEMO-MECHANICAL CARIES REMOVAL
Carisolv (Chemo‐mechanical caries removal )
0.5% sodium hypochlorite and 0.1 M amino acids “Glutamine,
leucine and lycine”
This is a technique used to remove caries and decay with minimal
Hypochlorite: dissolves the decayed dentine
Amino acid: buffering solution to prevent damage to the healthy
[The amino acid and hypochlorite will react with the denatured
Collagen Tissue of dentine (Infected dentine) making soft and easily
removed with hand instruments.]
Less anesthesia is used
Useful for children, dental‐phobic patients.
Useful for removing root or coronal caries in easily accessible
Removes the smear layer and doesn’t affect the bond strength of
the adhesive materials.
No histological effect on the pulp even with direct contact.
Ozone gas has a high oxidation potential and is
effective against bacteria, viruses, fungi, and protozoa.
Capacity to stimulate blood circulation, platelets, and
Ozone is used in dentistry in gaseous, ozonated water
and as ozonated oils
Ozone has been proven to halt root caries and also
reverse lesions (pit and fissure carious lesions) by
allowing the natural remineralisation process to proceed.
Remineralised lesions are known to be more resistant to
further dissolution than sound tooth surfaces.
Disruption of the protected ecological niche of the micro-
flora allows remineralisation from the saliva.
Intracanal irrigants in endodontic treatment.
Treatment of alveolitis, avascular osteonecrosis of the jaw,
and herpes virus infection.
Inhibits plaque formation: periodontal surgical and
Used in dental unit water line to disinfect water.
Advantage of ozone therapy is it is an atraumatic,
biologically based treatment.
O3 delivered from the HealOzone unit:
(2100 ppm O3, 615 ml/min) through a hand
piece with a silicone cup that sealed the
Once sealed, the device automatically
delivered the O3 for the treatment group
for 10 seconds followed by 10 seconds
After one and three months.
Prophylaxis of teeth
Re-examination using the DIAGNOdent® and
Ozone treatment repeat on each of these two
HAZARDS WITH CUTTING
MECHANICAL VIBRATION, HEAT, DESICCATION, LOSS OF
DENTINAL TUBULE FLUID, AND OR TRANSECTION OF
PULPAL SEQUELAE (RECOVERY OR NECROSIS) TAKE FROM 2 WEEKS
TO 6 MONTHS OR LONGER, DEPENDING UPON EXTENT AND
DEGREE OF TRAUMA.
The remaining tissue is effective in protecting the pulp
in proportion to the square of its thickness.
Steel burs produce more heat than carbide burs because
of inefficient cutting.
Dull instruments will plug debris, do not cut efficiently
and result in heat production.
When used without coolants, diamond instruments
generate more damaging heat than carbide burs.
Air alone as coolant: much lower heat capacity than
water, desiccates dentin, damage odontoblasts.
Soft tissue precautions:
Lips, tongue and cheeks of the patient.
Good access and visibility.
Isolation of the operating site: rubber dam, retraction type saliva
Wait for the instrument to stop or extremely careful while removing the
handpiece from the mouth.
Sudden reflex by the patients.
Hand excavators: soft caries removal in the deep preparation may lead
to mechanical pulp exposure: round bur at low speed.
Airborne particles, old restorations, tooth structure,
Strong high volume evacuation.
Loud noise: mental and physical distress, increase accident
proneness, reduce overall eficiency.
Noise level in excess of 75 db, 1000 to 8000 cps(frequency)
may cause hearing damage.
Amalgams or composites produce submicron particles and
Alveolar irritation and tissue reactions.
During cutting or polishing: thermal decomposition of
polymeric restorative materials (sealants, acrylic resins,
composites) : Monomers.
Mask : do not filter either mercury or monomer vapors
The removal and shaping of the tooth structure are
essential aspects of restorative dentistry. Modern high
speed instruments has eliminated the need of many
hand instruments, but hand cutting instruments are
still important for finishing many tooth preparations
and thus they remain as an essential part of the
armamentarium for quality restorative dentistry.
1. Sturdevant’s Art & Science of Operative Dentistry :4th edition
2. Fundamentals of Operative Dentistry; James B. Summitt; 3rd edition.
3. Operative Dentistry of Modern Theory and Practice: M K Marzouk
4. Black GV. A work on Operative Dentistry. Chicago: Medico-Dental
5. Dental Hand Instruments, 2003: Elsevier Science (USA). ISBN 0-
6. Fundamentals of Tooth Preparation: Shillingburg
7. Journal of Interdisciplinary Dentistry / Jul-Dec 2011 / Vol-1 / Issue-2