Instruments In Operative Dentistry Short Essays

Instruments Short Essays

Question 1. Classify hand-cutting instruments.


According To Gv Black:

1. Cutting Instruments.

  • Hand
  • Hatchet
  • Chisel
  • Hoe

2. Condensing Instruments Pluggers.

3. Plastic Instruments.

  • Plastic filling instrument
  • Cement carriers
  • Carvers

4. Finishing and Polishing Instruments.

  • Orangewood sticks
  • Polishing points

5. Isolation Instruments

  • Saliva ejector, evacuating tips.

6. Miscellaneous

  • Mouth mirror, probe.

Question 2. Hand-cutting instruments.


1. Excavators:

Excavators Types:

  • Hatches:
    • The cutting edge of the blade is directed in the same plane as that of the long axis of the handle
    • It is beveled
      • Uses:
        • Used in anterior teeth for preparing retentive areas
        • Sharpening of line angles
        • In preparation for a direct gold restoration
  • Hoes:
    • The cutting edge of the blade is perpendicular to the axis of the handle
      • Uses:
        • Planing tooth preparation walls
        • For forming line angles
  • Angleformers:
    • Monoangled instrument
    • The cutting edge is at 90 degrees to the bladder
      • Uses:
        • Sharpening line angles
        • Creates retentive features in dentin in gold restoration preparation
  • Spoon excavator:
    • Blades are slightly curved and cutting edges are either circular or clawlike
      • Uses:
        • To remove caries
        • Carves amalgam or direct wax pattern

2. Chisels:

  • Used for cutting enamel
  • Grouped into

1. Straight, slightly curved or bangle chisels:

  • It has a straight shank and blade with a bevel on only one side
  • The edge is perpendicular to the axis of the handle

2. Enamel hatchet:

  • Paired instrument
  • Blade angle 4590°
  • Bevel Unibevel/Bibeveled

Enamel hatchet Use:

  • Unibevelled instrument:
    • Cleaving of enamel
    • Planning of dentinal walls
  • Beveled:
    • Use in a chopping motion
    • Refine line and point angle

3. Gingival margin trimmer:

  • It is a modified hatchet with opposite curva¬ture and bevels
  • Paired instrument Distal and mesial
  • Instrument formula 7585 Mesial GMT, 95100 Distal GMT

Gingival margin trimmer Use:

  • Planning of gingival cavosurface margin
  • Removal of unsupported enamel
  • Bevel axiopupal line angle in Class 2

Question 3. Bur design.


  • The design of the bur includes the following

1. Blade or cutting edge:

  • It is in contact with the horizontal line or face

2. Tooth face:

  • The sides of the tooth head of the cutting edge in the direc¬tion of the rotation is the tooth face

3. Back of the tooth:

  • The opposite of the bur tooth is the back of the tooth

4. Rake angle:

  • It is the angle between the rake face and the radial line
    • Positive Rake Angle Radial line is ahead of the rake face
    • Negative Rake Angle Rake face is ahead of the radial line
    • Zero Rake Angle Rake face and radial line coincide

5. Clearance angle:

  • It is the angle between the back of the tooth and the work
  • Mostly it is straight and clearly defined

6. Tooth angle:

  • It is the measurement between the face and the back

7. Flute or chip space:

  • It is the space between successive teeth
  • The number of teeth in a bur is 6 or 8

Instruments in Operative Dentistry,.

Question 4. Instrument Nomenclature.


  • Order Purpose of instrument Example: Excavator
  • Suborder Manner of use Example: Push or pull
  • Class Form of working end Example: Hatchet, chisel
  • Subclass shape of the shank Example: Monoangle

Question 5. Instrument Formula.



  • Blade width
  • Represents the width of the blade in tenths of a millimeter


  • Blade length
  • Expressed in millimeter


  • Blade angle
  • The angle formed between the blade and the long axis of the instrument
  • Expressed in 100th of a circle


  • Cutting edge angle
  • The angle formed between the cutting edge and the long axis of the handle

Conservative And Operative Dentistry Instruments Instrument formula

Conservative And Operative Dentistry Instruments First digit of formula indicates width of blade of a millimeter

Conservative And Operative Dentistry Instruments Third number indicates length of blade in millimeters

Question 6. Chisels.


Chisels Types:

1. Straight chisels:

  • Straight blade in line with handle and shank
  • Cutting edge on one side

2. Monoangle chisels:

  • Blade angle to the shaft
  • Maybe medially or distally

3. Biangle chisel:

  • Two angles between the shaft and blade
  • Unibevelledmedially or distally

4. Triangle chisel:

  • 3 angles in the shank
  • Used for flattening the pulpal floor

Conservative And Operative Dentistry Instruments Chisel

Question 7. Excavators.


  • Used for removal of caries
  • Refining internal line angles

Excavators Types:

1. Hatchet:

  • The blade of the hatchet is perpendicular to the shaft
  • The cutting edge is parallel to the shaft
  • Paired i.e. right and left
  • Used for delicate cutting

2. Hoe excavators:

  • Single planed instrument
  • Unibevelled
  • Used with a push motion
  • Used for cutting axial walls

3. Spoon excavators:

  • Paired instruments
  • Double planed instruments
  • Used for removal of the decayed dentin

4. Cleoid excavator:

  • Blade resembles a claw
  • Used for amalgam carving, excavating decay in difficult areas

Conservative And Operative Dentistry Instruments Spoon excavator

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