Instruments in Operative Dentistry Notes

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Instruments Important Notes

1. Classification of instruments

  • According to Marzouck:
    • Exploring Instruments
    • Tweezer
    • Retractor
    • Probe/Explorer
  • An instrument for tooth structure removal
    • Excavators
    • Chisels
  • Restoring instruments
    • Spatulas
    • Burnishers
    • Condensers
    • Carvers
  • Finishing and polishing instruments
    • Stones
    • Brushes

2. Types of grasps:

  • Modified pen
  • Inverted pen
  • Palm and thumb
  • Modified palm and thumb

3. Materials used for sharpening stones:

Conservative And Operative Dentistry Instruments Materials used for sharpening stones

4. Speed ranges:

Conservative And Operative Dentistry Instruments Speed ranges

5. Common shank design

  • Straight
  • Latch type
  • Friction grip

6. Different instruments

Chisels:

  • Has a straight shank and bevel on one side only
  • Used with both pull and push motion
  • Used to cleave or split undermined enamel
  • Used to flatten pulpal floors

Enamel hatchet:

  • The cutting edge is parallel with the long axis of the handle and beveled on one side

Enamel hatchet Uses:

    • To split undermined enamel
    • For placing grooves

Gingival marginal trimmer:

    • It is an enamel hatchet with a curved blade
    • It is 4 figure formula instrument
    • Has cutting edge at an angle more than 90° to the axis of the blade

Gingival marginal trimmer Uses:

    • For bevelling gingival margin
    • For bevelling axiopulpal line angle

Hatchet:

  • It has the cutting edge of the blade directed in the same plane as that of the long axis of the handle
  • It is beveled

Hatchet Uses:

  • For preparing retentive areas in anterior teeth
  • For sharpening internal line angles for DFG

Hoe:

  • The cutting edge is perpendicular to the long axis

Hoe Uses:

  • To give form to the internal parts of the cavity used on the enamel of posterior teeth

Angle former:

  • It is a combination of GMT and chisels

Angle former Use:

  • For sharpening line angles or obtaining retention in dentin

Spoon excavator:

  • The cutting edge is either claw-like or circular
  • The circular is known as discoid
  • Claw-like is known as cloud

Spoon excavator Uses:

  • For removing caries
  • For carving amalgam

Knives:

  • Used for trimming excess filling material

Files:

  • Used to excess filling material, especially on gingival margins

7. Types of burs:

Conservative And Operative Dentistry Instruments Types of burs

Instruments Viva Voce

  1. When the second number in the instrument formula is 90100, the pair is used on the distal gingival margin
  2. When the second number is 7585 it is used in the mesial margin
  3. 100 and 75 pairs are used for inlayonlay preparation
  4. 90 and 85 pairs are used for amalgam preparations
  5. The modified pen grasp and inverted pen grasp are used universally
  6. The modified palm and thumb grasp is usually employed in the area of the maxillary arch
  7. Low speed is used for caries excavation, finishing, and polishing procedures
  8. High speed is used for efficient cutting and removing old restorations
  9. The neck of the instrument tapers from the shank diameter to a smaller size immediately adjacent to the head
  10. The neck transmits rotational and translational forces to the head
  11. Carbide burs normally have blades with slight negative rake angles

Instruments in Operative Dentistry

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