Wk 2: Adapation, Angulation, Strokes, Finger rest and fulcrums, Instrument classification

What is an instrumentation stroke?

The act of moving the working-end against the tooth surface.

What should not come in contact with the junctional epithelium (JE) during instrumentation?

Sharp cutting edges or tips.

In what directions can instrumentation strokes be made?

Vertical, oblique, horizontal, or multidirectional, which are a combination of all three directions.

In what direction are instrumentation strokes made relative to the soft tissue base of the sulcus or pocket?

In a coronal direction, away from the soft tissue base of the sulcus or pocket.

Where are vertical strokes used on anterior teeth?

On the facial, lingual, and proximal surfaces.

Where are vertical strokes used on posterior teeth?

On mesial and distal surfaces.

Where are oblique strokes used?

On the facial and lingual surfaces of posterior teeth.

Where are horizontal strokes used?

At line angles of posterior teeth; in furcation areas; in deep, narrow pockets; and on the narrow root surfaces of anterior teeth.

What are the three instrumentation strokes?

Assessment Stroke; Calculus Removal Stroke; Root Debridement Stroke.

What is the assessment stroke used for?

Used to evaluate the tooth surface; used with explorers to locate calculus deposits; used to reevaluate tooth surface after calculus removal.

What is another name for the assessment stroke?

Exploratory stroke.

What are the characteristics of the assessment stroke?

Fingers relaxed in modified pen grasp; flowing, feather-light stroke of moderate length; contacts the tooth, but no pressure is applied against the tooth surface for this stroke.

What is the calculus removal stroke used for?

Used to remove calculus deposits from the tooth surface.

What instruments are used with the calculus removal stroke?

Curettes and sickle scalers - blades.

What are the characteristics of the calculus removal stroke?

Short, controlled, biting stroke used to remove a calculus deposit from tooth; appropriately firm lateral pressure of cutting edge applied against the tooth during this brief stroke; at start of stroke, press fulcrum finger down against the tooth.

What is burnishing?

Removing only the outer layers of deposits is called burnishing.

What happens when calculus deposits are burnished?

Plaque biofilm continues to live on remaining burnished deposits. A smooth burnished deposit more difficult to remove.

How should large calculus deposits be removed?

Large calculus deposits should be removed in sections. Remove one section of the deposit at a time.

What is the root debridement stroke used for?

Used to remove calculus deposits from the root surface - same stroke, lighter pressure due to softness of the cementum.

What is lateral pressure?

The force applied by the clinician's index finger and thumb inward against the instrument handle and cutting edge directly against the tooth surface.

What are the three pressure forces of the instrumentation stroke?

Pinch pressure of fingers in modified pen grasp; pressure of the fulcrum finger to stabilize the hand; lateral pressure against the tooth during instrumentation stroke.

What pressure is used with an assessment stroke?

Light pinch pressure with grasp; light pressure on fulcrum; feather-light pressure as working-end moves over the tooth surface – GIVES US FEEDBACK; NO DEATH GRIP!

What pressure is used with a calculus removal stroke?

Instrument held with moderate pinch pressure; firm pressure against fulcrum; firm lateral pressure applied as cutting edge “bites” into tooth surface (hand rests between strokes).

How should the three pressure forces of instrumentation strokes be used ergonomically?

The three pressure forces of instrumentation strokes should be balanced during strokes. Unnecessary or constant firm pressure becomes a bad habit. Gauge amount of pressure, apply with brief pressure, and relax after each stroke.

How does lateral pressure differ by stroke type?

Assessment—requires feather light touch against tooth; Calculus removal—firm lateral pressure against tooth; Root debridement—less lateral pressure than calculus removal.

Why is the true angulation of teeth in dental arches important during periodontal instrumentation?

The placement of the working-end in relation to the tooth surface being instrumented is a critical element in periodontal instrumentation. A correct visual picture of true angulation of teeth in dental arches assists in correct placement of the working-end on root surfaces.

How are most teeth positioned in dental arches?

Most teeth are not positioned vertically in dental arches. Most teeth are tilted in dental arches.

What is the orientation of mandibular roots?

Mandibular anteriors: tilt inward; Mandibular premolars: more vertical; Mandibular molars: tilt outward.

What is insertion?

The act of gently sliding the working-end of an explorer or curet beneath the gingival margin into the sulcus or pocket.

What is the face-to-tooth surface angulation during insertion?

An angle between 0 and 40 degrees.

Why is the insertion angulation called a closed angle?

The face is closed against the tooth.

What are the steps for insertion?

Select correct working-end; establish secure finger rest near tooth; prepare for insertion by placing working-end on crown in the “Get Ready Zone”; the face is at a closed angle as the working-end slides gently to the base of the pocket.

What is the correct face-to-tooth surface angulation for calculus removal?

An angle between 45 and 90 degrees. Ideal is 60-80.

What occurs with correct angulation during calculus removal?

The cutting edge can bite into calculus and fracture the deposit.

What can incorrect angulation of the working-end result in?

Tissue injury or burnished calculus.

What happens when angulation is greater than 90 degrees?

Tissue injury.

What happens when angulation is less than 45 degrees?

Burnished calculus.

What is the ideal angulation for calculus removal?

60-80 degrees.

What is adaptation?

The positioning of the first 1 to 2 mm of the working-end’s lateral surface in contact with the tooth.

What are the three imaginary sections of the working-end?

Leading-third; Middle-third; Heel-third.

What part of the working-end is the key to correct adaptation?

Leading-third of Working-End.

For correct adaptation, what part of the working-end is always in contact with the tooth surface?

The toe-third or tip-third of the working-end is always in contact with the tooth surface.

What additional portions of the working-end can sometimes be adapted to the tooth?

In some cases, both the leading-third and the middle-third of the working-end can be adapted to the tooth.

What part of the working-end is NOT adapted to the tooth surface?

The heel-third of the working-end is NOT adapted to the tooth surface.

What can happen when the tip-third is NOT adapted?

The tip is sticking out and could cut the soft tissue.

What is rolling the instrument handle?

Turning the handle between the thumb and index finger.

What is the purpose of rolling the instrument handle?

Maintains precise contact of the working-end to the tooth surface as it moves around the tooth – adaptation.

What is the drive finger during rolling?

Either the index finger or the thumb, which determines the direction in which the working-end turns.

How does correct grasp affect instrumentation and adaptation?

Correct grasp allows the clinician to precisely control the working-end during instrumentation; correct grasp reduces musculoskeletal stress to hands and fingers; precise control of rolling the handle requires use of fingertips, not the finger pads, to grasp the handle; use the handle roll to position the working-end against the tooth surface.

What type of joint position supports instrument control?

Neutral Joint Position Using Fingertips.

What type of joint position hinders instrument control?

Hyperextended Joints Hinder Instrument Control.

What is the junctional epithelium?

The soft epithelial tissue forming the base of a gingival sulcus.

Why must the junctional epithelium be considered as the working-end moves across the tooth surface?

Sharp cutting edges or tips of instruments could injure the junctional epithelium.

What is motion activation?

The muscle action used to move the working-end of an instrument across a tooth surface.

What are the functions of the fulcrum during motion activation?

During activation the fulcrum finger supports weight of hand to increase stability; fulcrum assists in controlling movement of working-end; fulcrum acts as a “brake” to stop movement at end of stroke.

How large are instrumentation strokes?

Instrumentation strokes are TINY movements. The working-end moves only a few millimeters with each stroke.

What are the two types of motion activation?

Wrist-rocking motion; Digital activation.

What is wrist-rocking motion?

Hand, wrist, and arm work as a unit to produce rotating motion used to move working-end of instrument.

What are the characteristics and uses of wrist-rocking motion?

Less fatigue using wrist-rocking motion than finger movements; motion similar to action of turning a doorknob; used for all calculus removal with hand-activated instruments; allows clinician to maintain neutral upper body posture; keeps workload on forearm and wrist, instead of hand and fingers; fulcrum finger supports weight of hand.

What is digital motion activation?

Moving instrument by flexing thumb, index, and middle fingers.

How does digital motion activation move the instrument?

Moves instrument by making push-pull movements with fingers.

When is digital motion activation used?

Used whenever physical strength not required during instrumentation; used primarily with ultrasonic instruments, also used with periodontal probes, explorers; may be used to instrument restricted areas, such as furcations of multirooted teeth.

Is digital motion activation recommended for calculus removal with hand instruments?

Not recommended for calculus removal with hand instruments.

What is pivoting?

Slight swinging motion of hand and arm carried out by balancing on fulcrum finger.

What is a pivot used for?

Pivot is tiny movement used to reposition hand. Pivot supports object as it turns or rotates.

How does pivoting assist instrumentation?

Pivoting assists clinician in maintaining adaptation as the working-end moves around the tooth. Pivoting is used principally when moving around a line angle onto a proximal surface.

Why is correct adaptation important?

Correct adaptation of the toe- or tip-third to the tooth surface is essential for effective instrumentation. Correct adaptation of the working-end prevents injury to the gingival tissue.

How does correct grasp facilitate adaptation?

Correct grasp of the instrument facilitates rolling and pivot of the instrument handle for correct adaptation to the tooth surface.

What is a finger rest?

A fulcrum used to stabilize hand during instrumentation.

What are the benefits and purpose of a finger rest?

Improves precision of instrumentation strokes and prevents sudden movements that could injure patient. Purpose is to serve as a “support beam” for the hand.

What is an intraoral fulcrum?

Stabilization of dominant hand by placing pad of ring finger on a tooth near to tooth being instrumented.

What is an extraoral fulcrum?

Stabilization of nondominant and dominant hand outside of patient’s mouth, usually chin or cheek.

What is an advanced fulcrum?

Variation of intraoral finger rest used to gain access to root surfaces within periodontal pockets.

How do large and small motor skills relate to precision in instrumentation?

If a clinician’s large motor skills, such as position, are not correct, then it is impossible for their small motor skills, such as the finger rest, to be correct.

How should instrumentation skills be performed?

Successful instrumentation requires that you have an eye for detail. Each skill must be performed in a step-by-step manner, one skill at a time.

What grasp is used for an intraoral fulcrum?

Hold handle in modified pen grasp.

How should the ring finger and fingertip be positioned for an intraoral fulcrum?

Keep ring finger straight. Fingertip supports weight of hand.

Where should an intraoral fulcrum be located?

One to four teeth away from tooth being worked on; established out of the line of fire; never rest directly above tooth surface being worked on.

Where should an intraoral fulcrum rest?

Incisal edge or occlusal surface. Sometimes, the buccal or lingual surfaces need to be used – “hooking”.

What is the handle position for mandibular anterior teeth?

Palm DOWN. Rest handle against hand somewhere in green-shaded area.

What is the handle position for maxillary anterior teeth?

Palm UP. Rest handle against hand somewhere in green-shaded area.

What sequence should be followed while practicing fulcrums?

Me, My Patient, My Equipment, My Nondominant hand, My Dominant Hand, and Finger Rest.

What is Step 1: ME when establishing a finger rest?

Assure the relationship of the patient to the clinician is correct. Assume the correct clock position.

What is Step 2: My Patient when establishing a finger rest?

Establish patient head position: Chin up; Chin down; Turned toward; Turned away; Stay straight.

What is Step 3: My Equipment when establishing a finger rest?

Adjust the unit light and tray table/equipment.

What is Step 4: My Nondominant Hand when establishing a finger rest?

Grasp mirror and establish a finger rest – most likely extraoral.

What is Step 5: My Dominant Hand when establishing a finger rest?

Grasp the instrument. Pause to evaluate the grasp.

What is Step 6: My Finger Rest when establishing a finger rest?

Establish a finger rest near the first tooth to be worked on. Typically 1-3 teeth away.

What should be checked during Step 7: Pause and Self-Check Rest?

Fingertip on secure tooth surface? Ring finger straight, acting as support beam? Finger placement in the grasp, still correct?

How does finger length affect the location of the grasp?

Clinicians with longer fingers may establish grasp higher on instrument handle. Clinicians with shorter fingers may establish grasp lower on tapered portion of instrument handle.

What is a periodontal instrument’s design name?

School or person who designed instrument (e.g., Gracey).

How is each working-end identified on the handle?

Each working-end is identified by the number closest to it. The first number (on the left) identifies the working-end at the top. The second number is the working-end on the lower end of the handle.

What are the three instrument parts?

A. Handle; B. Shank; C. Working-End.

Why is handle design important?

Handle design is important in prevention of musculoskeletal injury during instrumentation.

What handle characteristics should be considered?

Instrument weight - compostion; Handle diameter – how big around – less “pinch force”; Taper – bigger near shank, skinny in middle?; Texture – knurling (ridges, etc.).

What are the characteristics of an instrument handle?

Solid or hollow; smooth or textured; 8 to 9 mm in diameter; easily accessible; round or octagonal.

What is pinch force?

Refers to force used to grasp the handle during instrumentation.

What can repetitive forceful pinching of an instrument cause?

Repetitive forceful pinching of an instrument can be a risk factor for carpal tunnel syndrome.

What handle characteristics require less pinch force?

Larger handle diameters and lightweight handles require less pinch force.

What is the effect of more pinch force?

More pinch force = muscle cramping.