Principles Of Periodontal Instrumentation

Principles Of Periodontal Instrumentation Including Scaling And Rood Planing

Instruments are sharpened to produce a functionally sharpened edge to preserve the shape and contour of instrument.

Periodontal Instruments Objectives of Sharpening

• To improve control of operator over the instrument.
• To reduce to working time.
• To reduce the burnishing of calculus.
• To reduce grooving or nicking of root surface.
• To improve tactile sensitivity.
• To decrease the fatigue and stress of clinician.

Types of Sharpening Stones Periodontal Instruments

• Sharpening stones from natural mineral deposits and produced artificially
  • Natural abrasive stones: Arkansas oil stones, India stone
  • Synthetically produced stone: Carborundum, ruby and ceramic stone

Read And Learn More: Periodontics Question And Answers

• Sharpening stones can be categorized on their method of use:
  • Mounted rotary stones: They are mounted on motor mandrel and are driven by motor. They may be cylindrical, conical and disc shaped. Not recommended for routine use.
  • Unmounted stones: They are available in variety of size and shapes, e.g. rectangular with flat or grooved surfaces, cylindrical or cone shaped.

Principles of Sharpening Periodontal Instruments

• Choose a suitable sterilized sharpening stone of appropriate shape and abrasiveness for the instrument sharpening.
• Establish the proper angle between the sharpening stone and the surface of the instrument.
• Maintain a stable, firm grasp of both the instrument and the sharpening stone. This ensures that the proper angulation is maintained throughout the controlled sharpening stroke.
• Avoid excessive pressure. Excessive pressure causes the stone to grind the surface of the instrument more quickly and may shorten the instrument’s life
• Avoid the formation of “wire-edge”. Characterized by minute filamentous projections of metal extending as a rounded ledge from the sharpened cutting edge.
• Lubricate the stone during sharpening this minimizes clogging of the abrasive surface of the sharpening stone with metal particles removed from the instrument. Oil should be used for natural stones and water for synthetic stones.
• Sharpen instruments during first sign of dullness. A grossly dull instrument requires the removal of great deal of metal to produce a sharp-cutting edge, which shortens the effective life of instrument.

Evaluation of Sharpness Periodontal Instruments

Sharpness can be evaluated by sight and touch.

• When a dull instrument is held under a light, the rounded surface of its cutting edge reflects light back. The acuteangled cutting edge of a sharp instrument, has no surface area to reflect light. No bright line can be observed.
• Tactile sensation by drawing the instrument lightly across an acrylic rod known as a “Sharpening test stick”. Dull instrument will slide smoothly.

Principles Of Periodontal Instrumentation

Write short note on instrument stabilization.
Or
Describe various instrument grasps and finger rests.
Answer. Stability of the instrument and the hand is the primary requisite for controlled instrumentation.

• Stability and control is essential for effective instrumentation and to avoid injury to the patient or clinician.
• The two factors that provide stability are, instrument grasp and finger rest.

Periodontal Instruments Instrument Grasp

• A proper grasp is essential for precise control of movements made during periodontal instrumentation.
• The most effective and stable grasp for all periodontal instruments is modified pen grasp. This grasp allows precise control to the working end, permits a wide range of movements and facilitates good tactile conduction.
• The palm and thumb grasp is useful for stabilizing instruments during sharpening and for manipulating air-water syringes.

Periodontal Instruments Finger Rest

• The finger rest serves to stabilize the hand and the instrument by providing a firm fulcrum, as movements are made to activate the instrument.
• A good finger rest prevents injury and laceration of the gingival and surrounding tissues.
• The ring finger is preferred by most clinicians for the finger rest. Maximal control is achieved when the middle finger is kept between the instrument shank and the fourth finger. This built-up fulcrum is an integral part of the wristforearm action that activates the powerful working stroke for calculus removal.
• Finger rests may be generally classified as intraoral finger rests or extraoral fulcrums.
• The standard intraoral finger rest generally rest on stable tooth surface immediately adjacent to working area.
• Following are the advanced intraoral finger rests
  • Modified intra-oral fulcrum: Achieved by combining an altered modified pen grasp with standard intra-oral fulcrum
  • Piggy-backed fulcrum: Middle finger rest on top of ring finger.
  • Cross-arched fulcrum: Accomplish by resting a ring finger on tooth on opposite side of arch from teeth being instrumented.
  • Opposite arch fulcrum: Accomplished by resting the ring finger on the opposite arch.
  • Finger-on-finger fulcrum: Accomplished by resting the ring finger on index finger.
• Basic extraoral fulcrums are
  • Palm up technique: Clinician rest the Knuckle against patient’s chin or cheek
  • Palm down technique: Clinician cups the patient’s chin with palm of the hand.