2nd dental students

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BY Dr
Mohamed H. Ghazy
Professor of Fixed Prosthodontics
October 10, 2013

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Classification
According to their uses
Diagnostic
Cutting
Restoring
Accessory

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Diagnostic instrument
A.Traditional diagnostic instruments:
 Mirror
 Indirect vision
 Light reflection
 Retraction
 Tissue protection
 Explorer(Probe)
 Distinguish areas of calculus.
 Distinguish decay.
 Distinguish areas of discrepancies on teeth.
 Cotton Pliers (Tweezers)
Carry, retrieve and place small objects.
 Locking
 Non-locking
 4. Periodontal probe
 Measurethe depth of salcus
 5.Articulating paper andholder
 B. New diagnostic instruments:
1. Digital radiograph.
2. Diagnodent Laser
3. Operating Microscope

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4. Intra-oral camera.
5. Loupes.
6. DIFOTI (Digital Imaging Fiberoptic Trans-
Illumination
Cutting instruments
Dependingonwhethermerehandor mechanicalforce,
areutilizedtowork outtheseinstruments:
 Hand cutting
 Powered rotary cutting
 Laser equipments
 Other equipments

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Hand cutting instruments
Manufactured from
 Carbon steel
 Stainless steel
 Carbide steel
 Other alloys of nickel, cobalt, chromium
Instrument design
 Blade(Working End)
 Portion of the instrument designed for a
specific function
 Shank
 Part of the instrument that attaches the
working end to the handle
 Handle
 Portion of the instrument where the
operator grasps

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Examples of Hand cutting instruments:
Chisels Hatchets Hoes
Marginal Trimmers Angle Formers
Examples of hand cutting
instruments.

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G.V. Black describe a way to name dental
instruments:
1.The purpose of its use e.g. excavator, condenser,
scaler.
2.The position or manner of their use e.g. push, pull.
excavator condenser scaler.
G.V. Black describe a way to name dental
instruments:.
3-The form of its working part, hoe, hatchet, chisel etc.
4-The number of angles in the shank, straight- no angle’
mon-angle (one angle), bin-angle (two angles), triple-
angle (three angles), quarternary-angle (four angles).
hoe hatchet
chisel
straight
mon-angle
bin-angle

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Powered (rotary) cutting
Instrument
Power sources for dental units
Electric motor
driven
Compressed air
•What does the term rotary mean?
•(Rotary is a part or device that rotates around an axis.)
•In dentistry, rotary instruments are attached to a handpiece.
Handpiece
is a device for holding rotary instruments,transmittingpower to them and for
positioningthem intraorally
According to shape
 Straight handpiece
 Contra angle handpiece

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Rotary speed ranges
 Low speed (below 12000 rpm)
 Medium speed (12000-200 000 rpm)
 High speed (above 200 000 rpm)

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Disadvantages of low speed
1- Ineffective
2-Time consuming
3- Require a relatively heavy force
application
Initial preparation of grooves and pinholes
Cleaning of teeth
Caries excavation
Finishing and polishing procedures
Uses of low speed
Advantages of high speed
 Faster removal of tooth
structurewith less vibration
and heat production
 Better control and greater
ease of operation
 Patient is less apprehensive
because annoying vibration
and operating time
decreased
 Instrumentslast longer

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Cutting tools
Dental rotary burs
Dental rotary abrasives
The rotary tools used in removing tooth structures may be
classified into burs and abrasives depending on whether
they work by an actual cutting or an abrading process.

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Design features
Shank
Neck
Head
Shank design
Definition It is the part that
fit into the handpiece, and
accepts the rotary motion from
it
Long shank
Used with straight handpiece
Short latch shanks
Used with latch type contra angle
handpiece
Friction grip shanks
Used with ultra high speed handpiece

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Neck design
It is the intermediate portion of an instrument that
connects the head to the shank
Function: transmit rotational force to the head
Head design
Is the working part of the instrument, the
cutting edge or portion of which perform
the desired shaping of tooth structure

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Characteristics of the head
1.Type of cutting: Bladed (bur).
Diamond abrasive.
2. Material of Construction:
Carbon steel.
Tungsten carbide.
Diamond ships.
Sand.
3. Head size
4. Head shape
Finishing
End cutting
End and
side cutting
Wheal
Pear
Fissure
Inverted cone
Round
Dental bur
(shape)

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Burs flute design
Cross cutPlain
Diamond abrasive instruments
Advantages
 Long life
 More effective in cutting enamel and dentin

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Diamond abrasive instruments
Fine
60-74µm
Medium
88-125µm
Coarse
125-150
µm
Very fine
38-44µm
Particle
size
Diamond abrasive instruments
The wheel stone
Round and oval shaped
stone
Cylindrical stone
Tapered stone
Inverted cone stone
Cup shaped stone
Barrel shaped stone
Pear shaped
Bud shaped
Root facer stone

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Wheel Round Spezial shapes
Pointed Torpedo Torpedo tapered
Cylinder Cylinder round Cylinder pointed
Pear Cone Trapered
Tapered round Wheel Round
Cylinder Cylinder round

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Pear Cerafil Egg
Flame Grenade Cone
Bud Tapered Tapered round

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 Ovalor flameShaped: used to reduce palataland
lingualsurfaces of anterior teeth.
 Wheel Stone: used to reduce incisal
edges in anterior teeth and occlusal
planes of cusps of posterior teeth.
 Wheel Stone may be with flat end,
round end or tapered ended stone.
 Barrel and Pear shaped stone: used
to reduce occlusal surfaces of
premolars and molars.
 TinkerStone: used to perform
shoulderwith bevel finishing line for
PFM restorations.
 Fisssure Stone as:
a. Tapered with round end used to perform
chamfer finishing line for full metal
restoration.
b. Tapered with flat end used to perform
shoulder finishing line for all ceramic full
coverage restoration.
c. Cylindrical stone. (long/short) used to
do grooves for partial coverage
restorations.

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According to function
 Reducer
 Cutter

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 Finishing
 Guidance Stone

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 Root Facer
 TissueTrimmer

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Discs
 Abrasive rotary instrumentsused for proximal
slicingor reduction.
 Supplied either mounted or demounted
 Used with conventional or slow speed
Discs classification
According to the
abrasive material
Carborandum
Diamond
Metal
Sand paper
According to size
Small 3/8 inch
Medium 5/8 inch
Large 7/8 inch

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Discs classification
According to shape
Flat shaped
Cup shaped
Accordingtothe side of
abrasivematerial
Safesided
Doublesided

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Accessory instruments and items.
Ultrasonic Hand piece
 Design
 Attached to the dental unit.
 Powered by electricity.
 Primarily used for prophylaxis
appointments.
 Attachments are similar in appearance to
scaling instruments.
 Delivers a pulsating spray of water

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Uses of the Ultrasonic
Handpiece
 Removecalculus
 Removestain
 Removebonding materials from tooth
surface after orthodontic appliances are
removed
 Removecement after orthodonticbands
are removed
Laser Handpiece
 Design
 Uses a laser light beam instead of
rotary instruments.
 Laser is conducted through a fiber-
optic cable.
 Resembles a standard handpiece.
 Maintains a water-coolant system.
 Maintains an air-coolant system.

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 Uses
 Cauterizes soft tissue.
 Vaporizes decayed tooth structure.
 Advantages
 Usually painless.
 Patient usually does not require anesthesia.
 Proceed with procedure faster.
 Disadvantage
 Cannot be used on teeth with existing restorations.
Air-Abrasion Handpiece
 Design
 Small version of a sandblaster.
 Produces a high-pressure delivery of aluminum oxide particles
through a small probe.

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Uses
•Prepares teeth for sealants.
•Removes external stains.
•Class I through class VI preparations.
•Endodontic access.
•Prepares a tooth surface for the
cementation of a cast restoration, such as
a crown or veneer.
Any Questions….

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BY Dr
Mohamed H. Ghazy
Professor of Fixed Prosthodontics
October 20, 2013
Studentquestion
Whatis the finish line?
a line indicatingthe location of the finish of a race

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Rotary cutting equipments.
 Low-Speed Handpiece.
 High-Speed Handpiece.
 Ultrasonic Handpiece.
 Laser Handpiece.
 Air-Abrasion Handpiece.
 Laboratory Handpiece.
Ultrasonic Hand piece
 Design
 Attached to the dental unit.
 Powered by electricity.
 Primarily used for prophylaxis appointments.
 Attachments are similar in appearance to
scaling instruments.
 Delivers a pulsating spray of water

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Uses of the Ultrasonic Handpiece
 Removecalculus
 Removestain
 Removebonding materials from tooth surface
after orthodontic appliances are removed
 Removecement after orthodonticbands are
removed
Laser Handpiece
Devices which produce beams of very high
intensity light
 Design
 Uses a laser light beam instead of
rotary instruments.
 Laser is conducted through a fiber-
optic cable.
 Resembles a standard handpiece.
 Maintains a water-coolant system.
 Maintains an air-coolant system.

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LASER WELDING
 The effect of laser depends on the power of the
beam and the extent to which the beam is absorbed
e.g.CO2 and ND:YAG Laser
 Uses
 Cauterizes soft tissue.
 Vaporizes decayed tooth structure.
 Advantages
 Usually painless.
 Patient usually does not require anesthesia.
 Proceed with procedure faster.
 Disadvantage
 Cannot be used on teeth with existing restorations.

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Air-Abrasion Handpiece
 Design
 Small version of a sandblaster.
 Produces a high-pressure delivery
of aluminum oxide particles
through a small probe.
Uses
•Prepares teeth for sealants.
•Removes external stains.
•Class I through class VI preparations.
•Endodontic access.
•Prepares a tooth surface for the cementation of
a cast restoration, such as a crown or veneer.

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Impression Trays
 Quadrant tray
 Covers one half
of the arch.
 Section tray
 Covers the anterior portion of the arch.
 Full arch tray
 Covers the entire arch.
 Perforated tray
 Holes in the tray create a mechanical lock to hold the
material in place.
 Smooth tray
 Interior of the tray is painted or sprayed with an adhesive to
hold the impression material.
Types of Stock Trays
Metal perforated tray
Mostly used for preliminary impression
Metal water coolant tray
Mostly used with reversible hydrocolloid
impression
Plastic perforated tray
Mostly used for preliminary and final
impression

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Crown remover
 Hand instrument.
 Crown remover.
Manual crown remover.
Pneumatic crown remover.
 Brass ligature wire.
 Chisel and hummer.
 Sectioning.
 Crown slitter.
The manual back action hammer is the
classic method for removing prostheses.
It produces the desired force by means
of a weight that slides along a shaft
Spring-loadedback action hammer
allows forces to be directed in a more
controlled manner.
Manual crown remover

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Automatic Crown & Bridge Remover
Non-traumatic way to remove crowns,
bridges and inlays
This water soluble, pliable resin adheres to porcelain, enamel,
gold, acrylic and will not damage restorations. Works quickly
and safely. Ideal for the removal of temporary or permanently
cemented crowns.

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Cord Placement Instruments
Crown Collars and Scissors
 Used to trim temporary crowns, gingival
cord and matrix bands.

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Instrument Sequence on a Tray
 Instrumentsset-up from left to right
 Basic set-up
 Additional examination instruments
 Hand cutting instruments
 Restorative instruments
 Accessory items
Preset restorative tray

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Cleaning and Sterilization of dental instruments
All instruments need to be cleaned and thoroughly
dried before they are sterilized.
Cleaning
Hand Scrubbing
Ultrasonic
Cleaning
Automated
Washer

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Classificationof Patient-CareItems
In order to determine the appropriate
treatment for any item that has been
used in patient care, you will need to
classify them into one of the following
three categories based on the risk of
infectionassociated with their intended use.
 Critical
 Semicritical
 Noncritical
CriticalItems
 Are defined as those
used to penetrate soft
tissue or bone
 Since the risk of
transmission would be
high, they must be heat
sterilized
 Examples:
 Surgical instruments
 Scalers
 Forceps
 Scalpels
 Bone chisels
 burs

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ClinicalApplication
 What do you use clinically everyday
that is considered a critical item?
 How do you treat these items before
they are used again?
Semicritical Items
 Touch mucous
membranes or non
intact skin
 Have a lower risk of
transmission. However,
if an item can be heat
sterilized, it should be
heat sterilized.
Examples:
Mouth mirrors
Amalgam
condensers
Impression trays
X-ray film holders

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 Semicritical instruments which cannot
tolerate the high temperatures of
sterilization must be processed by
using a sterilant or high level
disinfectant.
 These products achieve sterilization
(kills all forms of life including spores)
after immersion in the solution for 3
to 10 hours. Follow manufacturer’s
instructions for the product in your
office.
 Which items do you use daily which
are considered semi-critical?
 Do you routinely sterilize these
items?
 If not, what is your method for
assuring that they have remained in
the disinfectant or sterilant for the
necessary length of time?
Clinical Application

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ImmersionDisinfectantsFDA-
Approvedfor use in dentistry
 Sterilants:
Gluteraldehyde -6 to 10 hour contact time
Hydrogen peroxide (7.3%) 6 hour contact
time.
Gluteraldehyde and phen0ol/phenate-12
hour contact time
Hydrogen peroxide and peracetic acid-3
hour contact time.
High level Disinfectants
 Ortho-phthalaldehyde(12 minute contact time)
 Gluteraldehyde-20 to 90 minute contact time
 Hydrogen peroxide- 30 minutes contact time
 Gluteraldehydeand phenol/phenate-20 minute contact
time
 Hydrogen peroxide and peracetic acid-15 minute contact
time.
(You must always use personal protective equipment (PPE),
including utility gloves, mask, eyewear, and protective
clothing, when processing instruments)

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Definitions to remember….
 Sterilization is the process that kills all
microorganisms and is considered the
highest level that can be achieved. It is
accomplished by the proper use of
immersion chemical sterilants or by heat.
 High level disinfection is used when a
semicritical item cannot withstand heat
sterilization. Used correctly, it is
intended to kill disease producing
microorganisms but not spores. These
products are not used for surface
disinfection, but for immersion.
Noncritical Items
 Contact intact skin only.
 Have a low risk of disease
transmission.
 Some of these(*) should be
precleaned and disinfected
or barrier protected.  Examples:
Blood pressure
cuff
*X-ray cone
Stethoscope
*Lead apron

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Universal Sterilization
“…means that all reusable
instruments and handpieces are
sterilized (rather than disinfected)
between use on patients.
This provides the highest level of
patient protection.”
Miller & Palenik, p. 196
Steralization
 1. Steam autoclave:
Most effective.
Steam, heat (270 ° F), pressure (27 PSI).
for at least 6 minutes.
 2. Unsaturated chemical vapor:
Best for carbon steel instruments.
Heat (270 ° F), pressure (20-40 PSI).
for at least 20 minutes.

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3. Dry heat oven:
Heat (230 ° F) for 2 hours.
Temperature above 350 ° F may cause
premature instrument failure.
4. Chemical solution:
Used for materials that can not withstand heat
sterilization process.
Not recommended for metal dental
instruments.
Instrument processing flowchart
Remove
Items from
operatory
Use holding
Solutions if
necessary
Sterilize
Clean by
Automated
Or manual
method
Store
Package

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Ultrasonic cleaner
This solution is considered
highly contaminated.Retrieve
instrument cassettes while wearing
utility gloves
Don’t forget to close
the lid during
operationto reduce
aerosols!
A commercial all-purpose
ultrasonic cleaner.
(Courtesy of Certol.)
An enzyme ultrasonic cleanerin
tabletform.
(CourtesyofCrosstex.)
Copyright© 2009, 2006 by Saunders, an imprintofElsevier Inc. All rights reserved.

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Take care not to overload steam
heat sterilization equipment.
If steam cannot circulate and
penetrate,instruments may not
be sterile.
Packed handpiece

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Process Indicators
 Do not indicate sterility.
 Simply indicate that the
autoclave reached a
certain temperature.
 Show at a glance if a load
has been run.
Instrument Processing
Sterilization Monitoring
 Do not use instrumentpacks if chemical or
mechanical monitoringindicate inadequate
processing.

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Personal Protective Equipment
(PPE)
 Protects the skin &
mucous membranes of
the eyes, nose, and
mouth from exposure
to blood or OPIM
 Use of PPE is dictated
by the exposure risk,
not the patient.
Masks and Protective Eyewear
 Wear a surgical mask and
protective eyewear with solid
side shields to protect
mucous membranes of the
eyes, nose, & mouth
 Change masks between
patients, or during treatment
if it becomes wet

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Protective Clothing
 Wear long-sleeved reusable or disposable
gowns, clinic jackets, or lab coats to
protect skin of the forearms and clothing
likely to be soiled with blood, saliva.
 Change immediately if visibly soiled
Protective coverage

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Clinical Contact Surfaces
Housekeeping Surfaces
Environmental IC
 Use surface barriers to protect clinical contact
surfaces, especially which are difficult to clean.
 Change barriers between patients

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Digital Imaging
General Considerations
 Equipmentdifficult, if not impossible,to clean
and disinfect
 Barrier-protectclinical contact surfaces
FIXED EQUIPMENT AND PRODUCTS
Microblasters
PorcelainOvens
Burnout Ovens
Microscopes
Die Pinning System
Casting Machines
Porcelain

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Microblasters
Many options available:
 Choose from number of tanks
 Air pressure adjustment location
 SeeSynopsis of Laboratory Air-
Abrasion Units on the DIS
website
Renfert Basic Master
VanimanSandstorm Expert
Porcelain Ovens
IvoclarVivadent Programat P100
 Electronic vacuum control system
helps prevent firing errors if vacuum
is set incorrectly
 $3,876 w/pump
———
JelrusVIPVision 300
 User friendly
 Keypad let's you "NameThat
Program" from A-Z
 $2,399

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Porcelain Ovens (cont.)
VITAVACUMAT 4000
 Two thermocouples within the
chamber provide better
temperature control
 Automatic temperature
calibration after 100 hours of
usage
 Internal memory for up to 500
programs
 Portable, detachable keypad
 $5,836.50
Porcelain Ovens (cont.)
Whip Mix Pro Series
 Fast-cool feature
 Pressing furnace has
advanced cycles for
Inceram, Procera, pressing
and porcelain firing
 Pro Press 100 - $3,351
 Pro 100 - $2,500

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Burnout Ovens
Whip Mix Apollo II
 Unique feature is its bottom
loading lift platform that raises
and lowers investment rings
 Has an optional foot-control
switch
 Reduced heat blast
Microscopes
Meiji BM
 Dependable and inexpensive
 Easily adjustable
 $549
———
Renfert Mobiloscope
 Swivel arm microscope
 Space saving
 $1,111
 $1,438 w/fiber optic light
Meiji BM
RenfertMobiloscope

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Microscopes (cont.)
Nikon SMZ-645
 Versatile lab microscope
 $2,141 w/fiber optic ring light
and light source
Die Pinning Systems
RenfertTopSpin
 Tool-freedrill bit replacement
 Two working positions via swivel foot
on base
 $599
———
WhaledentPindex
 Foot-controlledor Hand-controlled
 Both are laser guided
 $599

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Casting Machines
KerrLabCentrifico
 Reliable broken-arm casting
machine
 Easy to use
 $479.50
Induction Casting Machines
Dentsply Ceramco Super
Cascom
 100 program digital memory
 Vacuum/pressure assisted
casting
 $15,000 retail price
———
Bego FornaxT
 Compact design
 Short heating time due to
infrared controller
 $12,473 retail price

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Porcelain
IvoclarIPS d.Sign Porcelain
 Produces esthetic restorations
 Mixes easily with minimal
slumping
 Comparable price to other
porcelain systems used in the
USAF (basic system-$717)
 RatedAcceptable by DIS
Porcelain
Vita Omega 900-3D
 Low-fusing ceramic
 Used for crowns, bridges,
laminates
 Reportedly compatible with
wide variety of metals
 Wear is reportedly similar to
natural teeth
 Standard kit - $1,696.00

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