College of Dentistry, Almajma University, Zilfi

 Name and identify parts of hand instruments  Differentiate between double and single ended instruments  Distinguish and use mono, bin and triple angled instruments  Define and identify primary cutting edge of blades

 Use and identify single and bi beveled inst  Name examination instruments  List uses of a mouth mirror, probe & tweezers  Identify and demonstrate use of various restorative instruments  Enumerate hand -cutting instruments

 Identify and mention use of hand-cutting instruments  Explain significance of instrument formula and describe 3 -digit formula  Name, identify and mention uses of restorative instruments  Name, identify and mention uses of accessory instruments used in operative dentistry

A tool or device used for specific purpose or task

Hand instruments Rotary instruments

 Stainless steel  Carbon steel  Alloys of Nickle, Chromium and cobalt

Handle (shaft) Shank Working End / Blade Slide 10

SINGLE ENDEDDOUBLE ENDED

 Mon angle  Bin angle  Triple angle

 Primary cutting edge  Secondary cutting edge

 Single beveled instruments  Bibeveled instruments

an edge that is not perpendicular to the faces of a structure مسطار الزوايا

Examination Hand-cutting Restorative Accessory

Mirror Explorer /probe Tweezers/ cotton pliers Periodontal probe Articulating paper holder

Slide 21

Indirect vision Light reflection Retraction Tissue protection

Slide 23

A: front view gives normal image B: Rear view mirror gives enlarged image

Distinguish areas of calculus Distinguish decay Distinguish areas of discrepancies on teeth

Measure the sulcus or pocket depth of the periodontium

used to check a patient’s “bite ”

Carry, retrieve and place small objects

NON-LOCKINGLOCKING

 Excavator  Hatchet  Gingival margin trimmer  Hoe  Chisel

used for the removal of soft dentin, debris, and decay from the tooth

excavators Bin-angle Tri-angle Mono-angle

Used for cutting enamel, and to smooth the walls and floors of cavity during preparation

Used to cut enamel and place bevels along the gingival enamel margins of the preparation

Used to plane the walls and floors of a cavity during preparation

Used to cut the enamel margin of the tooth preparation, form sharp lines, point angles, and place retention grooves  Straight chisel  Bin-angle chisel

chisels

Cutting instruments have formulas describing the dimensions and angle of blade

First two digits (15) designate the width of the blade in tenths of a millimeter It means 15/10 = 1.5 mm blade width

3 rd digit (8)designate its length in millimeters It means Length of blade = 8 mm

4 th & 5 th digit (14 ) represents the angle which the blade forms with axis of the handle expressed in hundredths of a circle (100 gradations or centigrades) It means 14% of a circle Circle = 360 degree Converting % into circle degrees 14/100 X 360 = 50 degree

It transfers amalgam from amalgam well to the cavity

condenses amalgam into the cavity

Amalgam carver carves amalgam after placement

Burnishes amalgam after insertion

Designed specifically for the placement of composite restorative materials  Anodized aluminum  Teflon

used for carrying dental materials to the prepared tooth structure

Cement Spatulas Used for mixing cements

Used for cutting dental dam material, retraction cord, and stainless steel crowns

Hold certain liquid, dental materials during a procedure

newly mixed amalgam is kept

 Define rotary instrument  Mention various rotary instruments  Identify and distinguish b/w high and low speed hand pieces  Mention speed ranges of high and low speed hand pieces  Mention uses of high and low speed hand pieces  Define a dental drill and mention its types

 Differentiate b/w a bur and a point  Name parts of a drill  Identify and name shank designs of drills  Name the material for making blade of commonly used burs  Name the material used for making commonly used abrasive points  Mention types of tungsten carbide burs  Identify & name basic shapes of burs 

 Mention various lengths of shanks of drill  Name and hold instruments using various grasp  Mention precautions to use rotary instruments

Hand Pieces Burs Polishing instruments

 Low speed  High speed

Low speed Speed ranges from 10,000 to 30,000 rpm Operates in clock and anti clock direction

Slide 61  Removal of soft decay  Finishing of a cavity preparation  Finishing and polishing restorations  Coronal polishing and removal of stains  Porcelain adjustments  Root canal treatment

Slide 62  Straight Attachments  Contra-Angle Attachment

High-Speed Handpiece Operates with air pressure Operates at speeds ,000 rpm Slide 64 Also known as Air-Turbine or Air rotor

Slide 65  Remove decay  Remove old or faulty restoration  Reduce crown portion of the tooth for preparation of a crown or bridge  Prepare outline and retention grooves for a new restoration  Finish restoration

1. Diamond and carbide cutting instruments remove tooth structure faster with less pressure and vibration 2. Number of rotary cutting instruments needed is reduced because smaller sizes are more universal in application 3. Operator has better control and greater ease of operation

4. Instruments last longer 5. patients are generally less apprehensive because annoying vibrations are decreased 6. Several teeth in the same arch can be treated at the same appointment 7. Operating time is reduced

The powered rotary instruments used for cutting and shaping a tooth or a prosthesis

 Bladed  Abrasive

They have bladed cutting heads and known as Dental Bur Made of tungsten carbide, steel, vulcanite

 Plain cut  Cross cut

For most Operative Dentistry procedures at high speed

For more efficient cutting at slow speed

 Diamond abrasives  Other abrasives

They are made of diamond which has abrasive action 

Diamond particles with some matrix are glued on a shaftand called Diamond points

 Many types of abrasive instruments are used in dentistry in addition to diamond instruments  They were at one time extensively used for tooth preparation, but their use is now primarily restricted to shaping, finishing & polishing

Slide 79

1. Shank 2. Neck 3. Head 1 2 3

Unlike shank in the hand-instruments, rotary instrument shank fits into a hand piece and accepts the rotary motion

Latch lock Friction lock

 It is used for LOW Speed Hand Pieces

 It is used for HIGH Speed Hand Pieces

16 mm 19 mm (most common) 21 mm 25 mm

Grasp handle with your thumb and first finger while your middle finger supports the instrument from underneath This is a favorite grasp for mouth mirror

Almost everything done in a dental office involves some risk to the  patient  Dentist  Auxiliaries

1. To pulp from the tooth preparation and restoration procedures 2. To soft tissues 3. To eye 4. To ear 5. Inhalation danger

 The use of cutting instruments can harm the pulp by exposure to mechanical vibration, heat generation, desiccation and loss of dentinal tubule fluid  As the thickness of remaining dentin decreases, the pulpal insult (and response) from heat or desiccation increases  Slight to moderate injury produces a localized, protective pulpal response in the region of the cut tubules  In severe injury, destruction extends beyond the cut tubules, often resulting in pulpal abscess and death of the pulp

These pulpal sequelae (recovery or necrosis) take from 2 weeks to 6 months or longer, depending on the extent and degree of the trauma Although a young pulp is more prone to injury, it also recovers more effectively when compared with an older pulp, in which healing and recovery are slower and less effective

 Enamel and dentin are good thermal insulators and will protect the pulp if the quantity of heat is not too great and the remaining thickness of tissue is adequate  The longer the time of cutting and the higher the local temperature produced, the greater is the threat of thermal trauma  Burs and diamond instruments that are dull or plugged with debris do not cut efficiently, resulting in heat production  When used without coolants, diamond instruments generate more damaging heat than carbide burs

 The lips, tongue, and cheeks of the patient are the most frequent areas of soft tissue injury  The handpiece should never be operated unless there is good access and vision to the cutting site  A rubber dam is very helpful in isolating the operating site  When the dam is not used, the dental assistant can retract the soft tissue on one side with a mouth mirror, cotton roll, and/or evacuator tip

 The dentist usually manages the other side with a mirror and/or cotton roll  If the dentist must work alone, the patient can help by holding a retraction-type saliva ejector evacuator tip, after it is positioned in the mouth

 With air-turbine handpieces, the rotating instrument does not stop immediately when the foot control is released  The operator must either wait for the instrument to stop or be extremely careful when removing the handpiece from the mouth so as not to lacerate soft tissues  The large disc is one of the most dangerous instruments used in the mouth  They should be used with light, intermittent application and with extreme caution

 When using high speeds, particles of old restorations, tooth structure, bacteria, and other debris are discharged at high speeds from the patient's mouth  The operator, assistant, and patient should wear glasses with side shields to prevent eye damage from airborne particles during operative procedures utilizing rotary instrumentation

 Precautions must be taken for prevention of eye injury from unusual light sources, such as visible light-curing units and laser equipment  Dental personnel and patients should be protected from high intensity visible light using colored plastic shields (attached to the fiber-optic tip)  Laser light can be inadvertently reflected from many surfaces in the dental operatory; therefore the operatory should be closed, and everyone should wear protective goggles

 Turbine handpieces at 30 pounds air pressure, may have noise levels as high as 70 to 94 decibels (db) at high frequencies  Noise levels in excess of 75 db in frequency ranges of 1000 to 8000 cycle per seconds (cps) may cause hearing damage

 The effect of excessive noise levels depends on exposure times  Normal use of a dental handpiece is one of intermittent application that generally is less than 30 minutes per day  Earplugs can be used to reduce the level of exposure but have several drawbacks  Room sound proofing helps and can be accomplished with absorbing materials used on walls and floors  Anti-noise devices can be used to cancel unwanted sounds

 A rubber dam protects the patient against oral inhalation of aerosols or vapors, but nasal inhalation of vapor and finer aerosol may still occur  Disposable masks worn by dental office personnel filter out bacteria and all but the finest particulate matter 

 Chapter 7  Sturdevant’s Art and Science of Operative Dentistry