1. 16-10-06 1
KOTHIWAL DENTAL COLLEGE AND
RESEARCH CENTRE
SEMINAR
ON
PRINCIPLES OF INSTRUMENTATION
GUIDED BY : PRESENTED BY :
DR RAJESH K. THAKUR DR MUKESH KUMAR
(M.D.S.) M.D.S. 1ST YEAR
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INTRODUCTION
To restore the health of periodontal tissues by
removing microbial plaque.
Achieved by following the proper principles of
instrumentation
To make the procedure untiring for operator and
patient, proper position of both, illumination,
retraction and visibility
The basic concepts of grasp finger rest, adaptation,
angulations and stroke must be understood before
clinical instrument handling.
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BASIC DESIGN
Single and double ended instruments
- single ended instruments are less efficient to use
- double ended instruments allow the clinician to
simply flip the instruments to use the other
working end.
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CONT..
Instruments handles
Instrument handle are available in a wide variety
of diameters and textures.
Characteristics of handle of instruments
• Weight-
• Diameter-
- small diameter handles (3/17 inch)
- large diameter handle (3/8 inch)
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CONT..
Texture
- handles with no texturing decrease control of
the instrument and increase muscle fatigue.
- handles with bumpy texturing maximize
control of the instrument and reduce muscle
fatigue.
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CONT..
Shank design
It facilitate placement of the working end
against the tooth surface.
- Simple shank design- a shank that is bent in
one plane (front to back) .
- Complex shank design- a shank that is bent in
two planes (front to back and side to side)
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SHANK FLEXIBILITY
RIGID FLEXIBLE
Larger in diameter. Thinner in diameter.
Heavy forces can be
applied.
Lighter forces can be
applied.
Lesser tactile sensation. Better tactile sensation.
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Functional and the lower shank
Functional shank-
- Allows the working end to be adapted to the
tooth surface.
- Begins below the working end and extends to
the last bend in the shank nearest the handle.
Lower shank-
- The portion of the functional shank nearest to
the working end
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WORKING END DESIGN
Parts of working end design
1. Face and back
2. Lateral surfaces
3. Cutting edge
4. Toe or tip
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ACCESSIBILITY
Position of patient and operator-
- provide maximal accessibility
Position of patient
Body
- supine position
- patients heels slightly higher than tip of nose
Head
- mandibular areas- chin down position
- maxillary areas- chin up position
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CONT..
Position of operator
- Head - tilt of 0 to 15 degrees.
- Shoulders - in a horizontal line .
- Back - straight or leaning forward slightly from the
waist or hips.
- Thighs - parallel to the floor; weight is evenly balanced
- Upper arms - parallel to the long axis of the torso.
- Forearms - parallel to the floor .
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VISIBILITY, ILLUMINATION
AND RETRACTION
Direct vision with direct illumination.
Indirect vision and indirect illumination.
Retraction provides visibility, accessibility and
illumination.
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CONDITION OF INSTRUMENT
Prior to any instrumentation , all instruments
should be examined to make sure that they are
clean , sterile, and in good condition.
The working ends of pointed or bladed
instruments must be sharp to be effective. Sharp
instruments enhance tactile sentivity and allow
the clinician to work more precisely and
efficiently.
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Dull instruments may lead to incomplete
calculus removal and unneccessary trauma to the
gingival tissues.
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MAINTAINING A CLEAN FIELD
Interferences in visibility, illumination and retraction.
- saliva
- blood
- debris
Removal of interferences
- saliva ejector
- aspirator
- gauze squares
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INSTRUMENT GRASP
Standard pen grasp- thumb, index finger, and
middle finger used to hold instrument.
Modified pen grasp- thumb, index finger, and
middle finger used to hold instrument.
Palm and thumb grasp- used for sharpening
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FINGER REST
The finger rest serves to stabilize the hand and the
instrument by providing a firm fulcrum
Classified as
Intra oral finger rest
-conventional
-cross arch
-opposite arch
-finger-on-finger
Extra oral fulcrums
-palm up
-palm down
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CONT..
Conventional finger rests - Established immediately
adjacent to working area.
Advantages
- provides the most stable, secured support for the hand
- provides leverage and power for instrumentation
- provides excellent tactile transfer to the finger
- permits precise stroke control
Disadvantages
- may be difficult to obtain parallelism of the lower
shank to the tooth surface for accessing deep pockets.
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CONT..
Cross-arch finger rests- Established on other
side of same arch.
Advantage
- allows improved access to the lingual aspect of
mandibular posterior teeth
Disadvantage
- decreases tactile sensitivity and makes strokes
difficult
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CONT..
Opposite arch finger rests- Established on
opposite arch.
Advantage
- facilitates access to deep pockets
Disadvantage
- decreases tactile information
- uncomfortable for patients with TMJ problems
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CONT..
Finger-on-finger-Established on index finger
or thumb of non operating hand.
Advantage
- provides stable rest to fulcrum finger
- improves access to deep pockets
Disadvantage
- non-working hand cannot be used for
retraction or to hold the mirror
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CONT..
Extra oral fulcrums
- Palm up – Established on resting backs of
middle and fourth finger on skin overlying
lateral aspect of mandible on right side of face.
- Palm down-Established on resting front
surfaces of middle and fourth finger on skin
overlying lateral aspect of mandible on left side
of face.
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CONT..
Extra oral fulcrums
Advantage
- facilitates instrumentation of the proximal root
surfaces of maxillary molars
Disadvantage
- least effective of all fulcrum techniques
- stroke control is more difficult and decreases
tactile information
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INSTRUMENT ACTIVATION
Adaptation- working end of periodontal
instrument placed against surface of tooth.
- objective of to make working end of
instrument conform to the contour of tooth
surface.
- on convex surface such as line angles adapt
within 1-2 mm working end against the tooth.
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CONT..
Lateral pressure- pressure created when force
applied against tooth surface with cutting edge
of bladed instrument.
- firm, moderate, or light
- for calculus it is firm or moderate
- root planing it is light
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CONT..
Strokes- three types
- Exploratory stroke- light feeling stroke,
evaluate pocket, calculus and irregularities.
- Scaling stroke- short, powerful pull stroke
- Root planing stroke- moderate to light pull
stroke
- activated by pull or push motion in vertical,
oblique, or horizontal direction
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CONCLUSION
Proper following of these principles of
instrumentation is must, because by
following this, treatment can be done
more efficiently, precisely and without
causing any iatrogenic injury to the oral
cavity.
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PRINCIPLES OF SCALING AND
ROOT PLANING
Scaling – It is the process by which plaque and
calculus are removed from both supragingival
and subgingival tooth surfaces.
Root planing – It is the process by which
residual embedded calculus and portions of
cementum are removed from the roots to
produce a smooth, hard, clean surface.
The primary objective of scaling and root
planing is to restore the gingival health.
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INSTRUMENTS FOR SCALING
AND ROOT PLANING
Universal curettes – all surfaces of the teeth can
be treated with one double ended instrument or
a matched pair of single ended instruments.
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CONT..
Gracey curettes – it is designed by Dr. Clayton
H. Gracey of Michigan in the mid 1930s.
- they are area specific
- only one cutting edge on each blade is used, the
blade is curved in two planes, and the blade is
“offset”.
- single cutting edge used
- blade curves in two planes
- offset blade
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CONT..
Principles of use
- determine the correct cutting edge
- make sure the lower shank is parallel to the surface to
be instrumented
- when using intraoral finger rests, keep the fourth and
middle finger together in a built-up fulcrum for
maximum control and wrist-arm action
- use extraoral fulcrums or mandibular finger rests for
optimal angulation when working on the maxillary
posterior teeth
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CONT..
on the Concentrate on using the lower third of the
cutting edge for calculus removal
Allow the wrist and forearm to carry the burden of the
stroke, rather than flexing the fingers
Roll the handle slightly between the thumb and fingers
to keep the blade adapted as the working end is
advanced around line angles and into concavities
Modulate lateral pressure from firm to moderate to
light depending nature of the calculus
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SUPRAGINGIVAL SCALING
TECHNIQUE
Calculus is less tenacious and less calcified than
subgingival calculus.
Sickles, curettes, and ultrasonic and sonic
instruments are most commonly used for the
removal of supragingival calculus.
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SUBGINGIVAL SCALING AND
ROOT PLANING TECHNIQUE
Subgingival calculus is usually harder than
supragingival calculus.
Curettes, hoes, files and ultrasonic instruments
are used.
