Lecture 4:Dental instruments and equipment Flashcards
4 main types of hand instruments
Periodontal probe
Explorer
Scaler (supragingival curette)
Curette (subgingival curette)
4 parts of the dental instrumnets
Handle– the part you grasp
Shape used depends on personal preference
Shank– joins working end to the handle
Length and curvature determines the teeth instrument able to access
Terminal shank– part of shank closest to the working end
Working end– portion of instrument that comes in contact with the tooth
What do the numbers on the sides of dental instruments mean
When the design name and number are stamped along the length of the handle, each working end is identified by the number closest to it.
When the design name and number are stamped around the instrument handle, the first number (on the left) identifies the working end at the top and the second number identifies the working end at the bottom of the handle
Explorers are used for
Usually found on a double ended hand held instrument with the dental probe on the opposite end
Used to
detect plaque and calculus
explore for cavities and tooth resorption
check for exposed pulp chambers
Explorers function by
Function by gliding along the tooth surface searching for irregularities
Its design increases operator’s tactile sensitivity
2 main types of explorers
Shepherds hook (most common)
Pigtail explorer– curved so only the tip can come in contact with the tooth
Periodontal probes are
Several different varieties available each with a different system of calibrated measurement (see text)
may be colour coded
Used to determine the amount of gingival pocketing
Function of gingival probes and how to use it
Function = determines depth of the sulcus
Inserted into gingival crevice and is gently walked along the entire circumference of the tooth
Weight of the instrument only!
Scalers are used for
Have 3 sharp sides and a sharp tip
Function = used for scaling calculus from the surface of the crown
Useful in removing calculus from narrow but deep fissures
Such as on the buccal surface of the 4th premolar
Scalers are used for supragingival calculus removal only!
Use subgingival can result in damage to the gingiva and periodontal ligaments
The ends of the instrument are mirror images so can be used on opposite tooth surfaces
Scalers are composed of
Sharp tip
The face
Lateral surface
Cutting edge – working part of the scaler
What do scalers look like
As with all hand instruments, scalers must be sharpened regularly, to be effective
Several types of scalers exist (see text)
Most common is the sickle scaler
Denoted as H6/7; S6/7 or N6/7 depending on the manufacturer
The end of the scaler is hooked behind the calculus and the instrument is pulled toward the tip of the crown
This pulls the calculus and all fragments away from gingival margin
Calculus should NEVER be pulled towards the gingiva!
Curettes are used for
Used for the removal of both supragingival and subgingival calculus
Curettes look like
Have 2 sharp sides and a rounded toe
The point of the curette (the toe) is rounded
The face of the curette is the concave side
The cutting edge is the edge between the lateral surface and the face
Curettes have a rounded back
Designed so that each end is a mirror image
2 types of curettes
Universal curette – can be adapted to almost all dental surfaces
Area specific curette – adaptable to different areas of the mouth
i.e. – Gracey curette
The higher the number of the instrument, the further back in the mouth it is used
Calculus removal forceps function and looks like
Function : used initially to remove large pieces of gross calculi
Has tips of different lengths and shapes
Longer tip placed over the crown; shorter tip placed under the calculus
Calculus is sheared off tooth when handles are brought together
Caution must be used to ensure the enamel surface of the tooth or the gingiva are not damaged
Why keep dental instruments sharp
Dental instruments should be kept sharp and true to their original design
Dental procedures are most effective when using sharp instruments because:
reduces fatigue
improves deposit removal
saves time
improves tactile sensitivity
minimizes patient discomfort
When to sharpen dental instruments
Repeated use of a dental instrument wears away minute particles of metal from the blade causing the cutting edge to take on a rounded shape resulting in a dull, ineffective blade.
A dull blade results in the loss of ability to “feel” the sharp edge “grabbing” onto a surface.
It may then seem that the blade is “sliding” over the surface or deposit which means you have to work harder to remove deposits.
For best results, dental instruments should be sharpened lightly after each use rather than reconditioning or recontouring after repeated use.
Curette and scaler care
Working edge can be dulled as a result of constant use and through steam sterilization
Sharpen each instrument after cleaning and disinfecting and before each use
Cleaning:
Rubber gloves should be used while cleaning instruments
Scrub the instrument using a scrub brush and detergent, under cold water
Use hot water to rinse the detergent off
Dry
Alternatively, ultrasonic instrument cleaners may be used
Ideally, several instrument packs should be available so that the instruments can be cleaned, sharpened, and sterilized between uses.
Sterilization reduces the risks of cross-infection among patients and from patient to staff members
If an instrument is sharp, its two planes come together at a precise angle
Visual inspection and sharpening sticks are appropriate methods to check for sharpness
Sharpening equipment
Stone(s)
Lubrication
Safety equipment
Instruments to be sharpened
Flat stones are
Arkansas
India
Ceramic
Arkansas stone
Arkansas stone- used for final sharpening of an instrument that is already close to sharpness
India stone
India stone- used for “coarse” sharpening of an overly dull instrument or for changing the plane of one or more of the sides of the instrument
Ceramic stone
may also be used for fine sharpening
With ceramic stones, water is generally used instead of oil
Steps in using flat stones
Sharpening with the India stone is followed by the use of an Arkansas stone
Both stones require oil for effective use
Conical stone
A round Arkansas stone
Used to provide a final sharpening to the instrument by working on its face
3 principles of sharpening
establish the proper angle
lubricate the stone
wear safety glasses
Why to establish the proper angle when sharpening
Before starting to sharpen, establish the proper angle between the stone and the surface to be ground
The plane of the surface being ground should be used as a guide
Do not tilt the stone so that it cuts unevenly across the surface being ground
Why to lubricate the sharpening stone
This avoids unnecessary heat, which changes the temper of the instrument, making the steel softer
A light touch is essential
Excessive pressure will heat the edge, even though the stone is lubricated
Sharpen the instrument at the first sign of dullness
Why wear glasses when sharpening dental equipment
This is the most important principle or precaution
ALWAYS wear safety glasses
Metal particles and the lubricant will be flying through the air and inevitably will strike eyes or face
The safety glasses are for your protection; WEAR THEM!
How to test sharpness by visual inspection
The instrument is held and rotated towards a bright light source
If the instrument is dull, the edge is rounded and reflects light
If the instrument is sharp, the edge does not reflect light
How to test sharpness on a sharpening stick
Use an acrylic or plastic rod, or syringe casing
To test, the edge of the instrument is drawn across the rod
A dull blade glides over the surface without catching at it
A sharp blade easily catches as the instrument is drawn over the surface
Power scalers are
Convert electrical or pneumatic energy into a mechanical vibration
When the power scaler is placed against calculus, the vibration shatters it, freeing it from the tooth surface
This vibration creates a tremendous amount of heat that can potentially damage the tooth
The scaler comes equipped with a water delivery system which produces a fine jet spray that cools the tooth
How to use a power scaler
The operator should use a light touch and keep the tip moving while traveling the circumference of the tooth, not stopping in any area
Power scalers operate in the range of 8,000 to 45,000 cycles per second
Types of power scalers
Ultrasonic scaler – converts sound waves into mechanical vibration
Sonic and rotary scalers – convert air pressure into mechanical vibration
How do ultrasonic scalers work
Ultrasonic instruments function in a way similar to that of 2 identically tuned tuning forks:
When one is caused to vibrate, the other starts to vibrate in resonance
Magnetostrictive and piezoelectric are 2 types of devices in the hand piece which can pick up the sound wave and turn it into a vibration
Ultrasonic metal strips/stack work by
Vibrate at 18,000, 25,000 and 30,000 cycles per second
Amplitude of tip movement in these units is between 0.01 and 0.05 mm (narrow motion)
Generally, lower amplitudes are better because they cause less damage to the tooth
Working tip is all sides, which results in an uneven motion and an elliptic pattern
2 lengths of inserts are available (remember when ordering and inserting!)
Ultrasonic Ferroceramic Rod work by
Vibrate at 42,000 cycles per second
Have an amplitude of 0.01 to 0.02 mm with a circular type motion (extremely narrow)
All sides of the tip are equally active (about 13 mm of the tip)
Ultrasonic and Combination Electric Motor Handpieces work by
Used for polishing and simple cutting of teeth
Electrical motor handpieces are generally not as effective as the air powered high-speed and low-speed handpieces
Piezoelectric works by
Uses crystals in the handpiece to pick up the vibration
Frequency ranges from 25,000 to 45,000 cycles per second.
Amplitude of these units is approximately 0.2mm, which results in a wide, back-and-forth tip motion (higher risk of damage to tooth)
approximately 3 mm of the working tip is active
Energy nodes: vibration energy is not distributed evenly down the tip of piezoelectric ultrasonic scalers
Motion of the piezo tip is not uniform: tip moves farther in one direction than in the other, which means that during use the most active side of the tip must be placed on the part of the tooth where the calculus is to be removed
Inserting magnetostrictive ultrasonic inserts
If a metal strip/stack unit is used, the unit must be turned on and the handpiece filled with water before insertion of the insert
If a ferroceramic rod unit is used, it should be drained before insertion of the insert
With either insert type, forcing the insert into a handpiece that is incorrectly set up can damage the insert
Ultrasonic medicaments in irrigation solutions
Many piezoelectric and Magnetostrictive units have reservoirs for an irrigating solution
A variety of solutions may be placed in the containers
The most popular and effective solution is 0.12% chlorhexidine
In-line reservoirs may be spliced onto the waterline, allowing irrigation solutions to be used in units that do not have their own containers
An alternative is to use a garden sprayer “bug buster” for the water supply
These units must be pressurized by hand
Sonic scalers are
Operate at 6,000 cycles per second and have an amplitude of 0.5 mm (slow, wider motion)
Motion is elliptic, in a figure eight motion
All sides of these tips are active during cleaning, but cleaning may not be even
Compressed air has a cooling effect so less likely to cause heat-related damage to teeth than ultrasonic cleaners
How do sonic scalers work
Air enters sonic scaler, passes through the shaft, and exits from small holes on the shaft that are covered by a metal ring
Air exits the hole at an angle and causes the ring to start spinning
Because the ring doesn’t fit the shaft tightly, it begins to wobble
This wobbling sets off a vibration that is transmitted down the shaft to the tip
Two driving mechanisms used for polishing and drilling
electrical power
air power
Electrical power used for polish and drilling
Least expensive
Operate at lower speeds than air powered but have higher torque (the ability to overcome resistance to movement)
Cannot use water – unless an expensive unit
Two types of air power for drilling and polishing
Air compressor→pumps air either directly into the dental unit or into a storage tank for slow release to the dental unit
Compressed gas→either room air or nitrogen
Because of the associated hazards, oxygen and carbon dioxide should not be used
Oxygen is explosive and carbon dioxide may be toxic
How air power uses for drilling and polishing
Take the room air and compress it to drive the handpieces
Most work by pumping air into an air-storage tank
The compressor pumps air into the tank until the pressure inside the tank reaches between 80 and 100 psi (pounds per square inch)
Air is bled from the tank as it is used by the handpiece at a lower pressure, usually 30 to 40 psi
When the pressure drops below the minimum pressure in the tank (around 60 psi) the compressor turns on again and refills the tank
Air compressor care
Most air-compressor systems use oil for lubrication
The oil level must be monitored frequently to ensure it is adequate, or the compressor can cease up
Some systems use a dipstick for checking the oil; others have a porthole in the side of the oil reservoir
Always use the type of oil recommended by the manufacturer
Compression of air into the storage tank may cause condensation
Air storage tanks have a drain cock that can be turned to let the water out of the tank
Failure to do so not only can ruin the compressor it also allows water to fill the tank decreasing the effectiveness of the system
Air compressor system handpieces
Low and high speed hand pieces
Low speed air hand pieces
Polishing with prophy angles
Performing other dental procedures with contra angles
High speed handpieces in air power is
Cutting teeth during extractions
Making access holes into teeth in root canal therapy
All hand pieces in air power use
All handpieces use a rubber gasket to ensure a water-air tight seal
Make sure the gasket is connected when connecting the handpiece
Low speed attachments on air power
Prophy angle - allows the use of a prophy cup for polishing teeth during cleaning
Special files - used for engine-driven root canals
Slow-speed burs - for cutting and smooth restoration
Contra angle - is used to change either the direction or speed of rotation
Care for low speed handpieces
Must be lubricated at the end of use
Lubrication is inserted first in the smaller of the two large holes using the oil or spray that comes with the handpiece
WD40© may be sprayed into the handpiece every two weeks to remove residues, followed by the recommended lubricant
Prophy and contra angles (attachments to the handpieces)
Generally, prophy heads should be lubricated weekly with prophy angle lubricant
Some prophy angles are self-lubricating
Consult manufacturer’s instructions for correct procedures
High speed handpieces work by
Turn at 300,000 to 400,000 revolutions per minute
Used for cutting teeth for exodontics, making root canal entries, and other procedures
two types of bur handpieces for high speed
Push button to open the chuck
Bur is removed or replaced by pressing the button
Chuck key to open the chuck
Key is twisted counterclockwise to loosen and remove bur and clockwise to tighten
Burs
Burs should be treated like sharps and disposed of in the sharps container
They should be removed from the handpiece when not in use
If the bur is removed from the handpiece a blank should be put in its place to prevent damaging the chuck if handpiece gets accidentally turned on
Bur selection
It is very important that you know the type of handpiece that the bur is to be used in to prevent damaging the bur (ie: slow or high speed)
Remember burs used for extractions and other treatments are the responsibility of the veterinarian
There are several types of burs available (see text), which types are used depends on the skills of the veterinarian in your practice
Care of high speed hand pieces
Lubrication
Should be lubricated daily with a spray-type cleaner and lubricant recommended by the manufacturer
Turbine maintenance
Internal portion of the high-speed handpiece that spins at extremely high speeds
Three way syringe do
Come with most dental units
Two buttons:
Water spray→ used to irrigate a tooth surface and clear away prophy paste, tooth shavings, and other debris
Air spray→ used to dry the field
Caution must be used to prevent flushing air into tissues; air can create subcutaneous emphysema, or enter a blood vessel creating an embolism
Pressing both together creates a mist
Lighting and magnification in dentals
“If you can’t see it, you can’t do it”
Surgical lights produce a wide-ranging, even lighting
A headlamp will give spotlighting
Focal lighting is achieved by the use of fiber optic lights built into a handpiece
Binocular eyeglasses produce the best type of magnification
3 powered magnification, with a focal length of between 15 and 18 inches, enlarges the subject without excess distortion
Signs high speed hand pieces need to be replaced
Subject to wear over time and must be replaced – signs:
Chuck won’t tighten around bur
Increased noise or vibration
Roughness when handling
Intermittent stopping of handpiece
Handpiece won’t function
