Chapter 19

Chairside Instruments and

Tray systems.

Structural Parts of Dental Hand Instruments

• Working End– The end of the instrument that actually

performs the function.– Comes in three generalized categories.

• Point

• Blade

• nib

Descriptions of the working end!

• Point: – sharp tip

used to:

• explore and detect.– Example: explorer

Description of working end cont.

• Blade:

• flat or curved,

• rounded edge or a cutting edge.

• beveled or bi-beveled, – Example:

• Gregg 4/5 (round edge),

• Hollenback carver, (beveled edge).

Description of working end cont.

• Nib:

• a blunt or flat end.

• serrated or smooth.– Example: – Amalgam condenser, – Endodontic plugger.

Classification of Dental Instruments

• Instruments are classified by:– Number of working ends.– Function.– Manufactures name.– Black’s number formula.

Number of working ends

• Single-ended: – one working end

– generally a longer handle.

– single function

– multi-function

• Double-ended:– ends are same,

– opposite directions

– different functions

– different sizes

– paired left and right

– mesial or distal

Instruments classified by function

• CUTTING: – used to design (shape or form)

the cavity prep, – define and refine walls / floor of the prep.– Cuts enamel and dentin.

The six cutting hand instruments

• 1. Chisels: shapes the walls,– pushing motion.

• 2. Hatchets: refine walls / retention, – paired left and right.

• 3. Hoes: smooth and shape the floor– pulling motion.

• 4. Angle formers: defines point angles.– corners of the prep. downward pushing motion.

Chisel Hatchet Hoe Angle former

Cutting instruments cont.

• 5. Gingival margin trimmer (GMT)– double ended instrument– comes paired mesial and distal.– Are used to bevel (slant or angle) the gingival

margin of the cavity prep.– cuts enamel. It does not trim the gums.

GMT distal GMT mesial

Cutting instruments cont.

• 6. Excavator, AKA Spoon excavator– scoop and remove

caries and debris from the prep/tooth.

– Double ended

– Used when there is a risk of perforating into the pulp chamber with the handpiece and bur.

Non-cutting hand instruments.

• Includes the basic set-up.– Mouth mirror– Explorer– Cotton pliers

• AKA cotton forceps or pick-ups.

• This is a guideline for a basic set-up. Your dentist will determine which instruments they would like in their basic set-up.

Examples ofNon-cutting instruments cont.

• Periodontal probe • Amalgam carrier • Gregg 4/5 aka “plastic

instrument”• Amalgam condenser

• Spatula• Articulating paper

forceps• Scissors: (they don’t

cut tooth structure)• Burnisher

Carving instruments.

• Carvers are used to carve amalgam not tooth structure!

The three main carver are listed next. There are others. The ones you have in your office will depend on the doctor.

Carving instruments cont.

• T-3 carver: • carves amalgam occlusal and interproximal

• Hollenback carver: • carves amalgam interproximal.

• Cleoid-Discoid carver: aka (C-D) • carves amalgam occlusal.

• All can be used to carve anatomy (pits and fissures) into the occlusal surface.

Cleoid-discoid Hollenback T-3

Dental Rotary Instruments

• Burs, aka rotary instruments!– discs,

– stones,

– rubber polishers,

– mandrels,

– lab burs.

• Used for – cavity preparation,

– finishing and polishing restorations,

– surgical procedures

– adjusting appliance.

Parts of the bur!

• Shank: – the part of the bur you

place in the chuck of the handpiece.

• Straight shank: – are longer, larger

shanks

– associated with lab burs.

• Latch-type shank: – has a notch

– contra-angle attachment

– slow-speed handpiece

• Friction-grip shank: – smooth on the end

– high-speed handpiece

Parts of the bur cont.

• Head: – is the working end of

the bur. It performs the function.

– different shapes

– different sizes

– different # of blades

• Neck: – is the tapered part of

the bur that connects the shank to the head of the bur.

Cutting Burs

• Round: FG or latch, opens the tooth and removes caries. Sized 1/4 - 10

• Inverted cone: FG or latch, removes caries and place retention grooves / undercuts. Sized 331/2 - 37 or 37L (long)

Cutting burs cont.

• Straight fissure:• Sized 56 - 58L

• Cross-cut straight fissure:

• Sized 556 -558L

• Tapered fissure: • Sized 169 - 171L

• Cross-cut tapered fissure:

• Sized 699 - 701

Straight Cross-cut Tapered Cross-cut fissure straight fissure fissure tapered fissure

Cutting Burs cont.

• End cutting:– form the shoulders of

crown preps.

• Wheel: – used to form retention

in the prep.

• Pear: – used to open and extend

the prep. Sized 329-331L.

• Diamond burs: – rapid reduction of

tooth structure.

– polishing and finishing

– occlusal adjustments.

– Identified by grit: • (fine, med., coarse)

– Many different shapes and sizes.

Diamond burs.

Additional Burs

• Finishing burs: – smooth, trim, and

finish restorative material.

– increased # of blades

– different shapes and sizes,

– gold colored shank

• Surgical burs: – FG or latch grip,

– reduce, remove, or reshape the bone and to section (cut) a tooth into pieces.

– Come in many shapes and sizes, (same as the cutting burs), shaft of the bur is longer

Additional burs cont.

Additional burs cont.

• Stones: used for cutting, polishing and finishing restorations and appliances.– Many different shapes

and sizes.

– Common stones used, white and green stones. (darker the color the more abrasive the material.)

• Rubber points or cups: aka greenies, and brownies.– FG or latch.

– polish metals and define anatomy in restorations.

– polishing amalgam and gold

Additional burs cont.

Additional burs cont.

• Lab bur: AKA acrylic bur or a vulcanite bur.– Used to adjust

appliances, extraorally.

– slow speed motor and nosecone,

– used in a lathe in the dental lab.

– Many different shapes and sizes.

• Mandrel: designed to hold polishing disks.– used to smooth, polish

and adjust composite.

– different grits,

– discs are made of:

– metal,

– plastic,

– paper.

Additional burs cont.

Bur Blocks

• Bur blocks – hold, separate, and

organize burs.

– set up by bur, doctor, or procedure.

– magnetic

– different shapes and sizes,

– autoclaveable.

•

Handpieces

• Parts of the handpiece– Working end: where

the bur is placed

– Shank: the part of the handpiece you hold onto. AKA the handle.

– Connection end: the end that attaches to the power source or line.

•

High speed handpiece

• Spins at 400,000 rpm• rapid cutting of tooth

structure • finishing restorations.• Produces frictional

heat– pulpal damage.

– Spray water.

• No attachments – just burs.

• Speed is controlled by the rheostat.

• Fiber optic light source

• Do not place in ultrasonic!

Slow-speed handpiece

• AKA low-speed, or straight handpiece.

• Rotates about 30,000 rpm.

• Used with a contra-angle or pro/right angle attachment.

• No water, but can and does produce frictional heat.

•

Instrument tray systems

• Pre-set trays: very common, saves time.• Instruments should be set according to the

order they will be used. This may vary from doctor to doctor.

• Color-coding: may be used to identify:– Which procedure they are for.– Which operatory they belong in.– Which doctor they belong to.

Instrument tray systems

Closing

• Knowing and understanding dental instruments is a very important part of your job.

• This is a foundation for you to build you instrument knowledge.

• Any question?