DHYG 1331 Sickle Scalers Ant. and Pos.

Sickle Scaler

A periodontal instrument used to remove calculus deposits from the crowns of the teeth

Should NOT be used on root surfaces

Design characteristics

• - pointed tip and back

• - triangular in cross section

• - 2 cutting edges per working-end

Design Characteristics

The face of a sickle scaler is perpendicular to the lower shank

Anterior Sickles

• often single ended

• may have 2 different sickles on a double-ended instrument

• 
  

Posterior Sickles

usually 2 sickles paired on a double-ended instrument

working-ends are mirror images

Cross section of the sickle scaler

triangular cross section

(this design limits use to above the gingival margin since the pointed tip and back could cause tissue trauma)

working-end of a sickle scaler

pointed back and tip

2 cutting edges per working end

Face of the sickle scaler

perpendicular to the lower shank so that cutting edges are level with one another

• - level cutting edges = the lower shank must be tilted slightly toward the tooth surface to establish correct angulation

Application of sickle scaler (anterior vs posterior)

anterior teeth: only 1 single-ended instrument is needed

posterior teeth - one double-ended instrument is needed

Primary Functions of the Sickle Scaler

• - removal of medium- to large- sized calculus deposits

• - excellent for calculus on the (1) proximal surfaces of anterior crowns and (2) enamel surfaces apical to the contact areas of posterior teeth

• Debridement of enamel surfaces; NOT recommended for use on root surfaces

Anterior/Posterior Designs

Anterior: used on the crowns of anterior teeth

Posterior - used in posterior sextant; but can be used on anterior teeth also. (usually, double-ended that are mirror images of each other)

Nevi 1: Sickle End

• - sickle-end of the Nevi 1 instrument

• rigid shank

• - small, thin sickle

• - use on coronal surfaces of anterior teeth

Nevi 1: Disk End

• - Disk-end of the Nevi 1 instrument

• - all surfaces are sharp on the disk-end

• - supragingival use on lingual surfaces of anterior teeth

Nevi 2

• - paired, mirror-image working-ends

• - thin, curved sickles for use on posterior teeth

• - long cutting edge facilitates access to proximal tooth surfaces

• - use on coronal surfaces of posterior teeth

Nevi 3

• - paired, mirror-image working-ends

• - thin, curved sickles for use on posterior teeth

• - long cutting edge facilitates access to proximal tooth surfaces

• - use on coronal surfaces of posterior teeth

• excellent for use on pediatric patients

Nevi 4

• - paired, mirror-image working -ends

• - strong, curved sickles for use on posterior teeth

• - rigid working-end shank

• - removal of medium or large size deposits

Picture of Anterior Sickle Scaler

posterior sickle scaler picture

Angulation/Insertion

Angulation: the relationship between the face of a calculus removal instrument and the tooth surface

Insertion: sliding the working-end beneath the gingival margin into the sulcus or pocket

With correct angulation the cutting edge can bite into calculus and fracture the deposit

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

between 45 and 90 degrees

60 to 80 is ideal

Insertion picture

Angulation picture

Incorrect Angulation on working-end: greater than 90 degrees

one cutting edge will contact the lining of the pocket, causing tissue damage

Incorrect Angulation on working-end: less than 45 degrees

cutting edge will slide over surface of deposit

angle greater than 90 degrees picture

angle less than 45 degrees

How is correct angulation achieved by?

Tilt the lower shank toward the tooth surface

• - face-to-tooth surface angulation: 70-80 degrees

Correct vs incorrect angulation

What is adapatation?

The act of placing the first 1-2mm of the working-end’s lateral surface in contact with the tooth

Sections of the working end

1. 1. Leading Third (anterior portion of the working end)

2. 2. Middle Third

3. 3. Heel Third

Picture of Leading Third

Step 1 for adaptation and angulation for anteriors:

begin at the midline of the tooth and work toward the proximal surface

Step 2 for adaptation and angulation for anteriors:

Position the tip-third of the working-end near the midline of the tooth

tilt the lower shank toward the tooth surface to establish correct angulation

Step 3 for adaptation and angulation for anteriors:

Make strokes across the facial surface toward the mesial surface

step 4 for adaptation and angulation for anteriors:

at the line angle, roll the instrument handle to maintain adaptation of the tip-third of the working-end

Step 5 for adaptation and angulation for anteriors:

continue making strokes are you work along the mesial surface

Step 6 for adaptation and angulation for anteriors:

Be sure to make strokes at least

halfway across the mesial surface

Adaptation to Interproximal

Correct

Adaptation to Interproximal

Incorrect

correct

incorrect

trauma for incorrect adaptation

Posterior Sickle Correct

Working End

Lower shank is parallel to the distal surface

Functional shank goes up and over the tooth

Posterior Sickle Incorrect

Working End

Lower shank not parallel

Functional shank is down and around the tooth

step 1 posterior sickle

select the correct working-end

step 2: posterior sickle

Position the tip-third of the

working-end at the distofacial line

angle.

Work back toward the distal surface

step 3: posterior sickle

Check your angulation

Tilt the lower shank toward the

tooth surface

Posterior Sickle Correct

Angulation

The face should be at a 70- to 80-

degree angle to the distal surface

step 4: posterior sickle

Reposition at the distofacial line

angle with the tip “facing” forward

Tilt the shank toward the tooth

surface

step 5: posterior sickle

Make strokes across the facial

surface

step 6: posterior sickle

Roll the instrument handle to

maintain adaptation at line angle

Tilt lower shank toward the mesial

surface

step 7: posterior sickle

Continue strokes at least halfway

across the mesial surface

posterior sickle incorrect angulation

calculus removal stroke

Assessment Stroke

Purpose: to assess tooth anatomy; detect calculus and other plaque retentive factors

Used with: probes, explorers, curets

Lateral Pressure: contact with tooth surface, but little pressure

Character: flowing, feather-light stroke of moderate length

Number: many overlapping strokes to evaluate the entire root surface

Calculus Removal Stroke

Purpose: to lift calculus deposits off of the tooth surface

Used with: sickle scalers, curets

Lateral pressure: firm pressure against tooth surface

Character: brief, tiny biting stroke

Number: limited to areas with calculus deposits

Root Debridement Stroke

Purpose: to completely remove all residual (remaining) calculus deposits; disrupt plaque biofilm from root surfaces within deep periodontal pockets

Used with: area-specific curets

Lateral pressure: moderate pressure against tooth surface

Character: shaving stroke of moderate length

Number: Many, multidirectional strokes, covering the entire subgingival root surface

The Calculus Removal Stroke With Sickle Scaler: Stabilization

Apply pressure with the index finger and thumb inward against the instrument handle and press the tip of the fulcrum finger against the tooth surface

Calculus Removal Stroke With Sickle Scaler: Adaptation

tip-third cutting edge is adapted

Calculus Removal Stroke With Sickle Scaler: Angulation

70 to 80 degrees; for sickle scalers, the lower shank must be tilted slightly toward the tooth surface to achieve correct angulation

Calculus Removal Stroke With Sickle Scaler: Lateral Pressure for Calculus Removal

Moderate to firm pressure against the tooth surface is maintained during the short, controlled calculus removal stroke made away from the soft tissue

when making a stroke, the instrument handle moves slightly away from the tooth surface being instrumented; for example, when working on a facial surface the instrument handle moves slightly toward the cheek or lip and not toward the facial surface

Calculus Removal Stroke With Sickle Scaler: characteristics

controlled strokes, short in length

Calculus Removal Stroke With Sickle Scaler: Stroke Direction

Vertical strokes are most commonly used on anterior teeth and on the mesial and distal surfaces of posterior teeth; stroke direction is away from the soft tissue (in a coronal direction)

oblique strokes are most commonly used on the facial and lingual surfaces of posterior teeth; away from the soft tissue (in a coronal direction)

horizontal strokes are used at the line angles of posterior teeth and the midlines of the facial or lingual surfaces of anterior teeth; stroke direction is parallel to the gingival margin, but never touching the soft tissue base of the sulcus or pocket

Calculus Removal Stroke With Sickle Scaler: stroke number

strokes should be limited to areas where calculus is present; use the minimum number of strokes needed to remove calculus deposits

Characteristics of a Calculus

Removal Stroke

Short, controlled, biting stroke used to remove a calculus deposit from

tooth

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

Balances of forces with instrumentation stroke: pinch grasp

Assessment stroke: relaxed

Calculus removal stroke: firm (but not death grip)

Root surface debridement stroke: moderate

Balances of forces with instrumentation stroke: fulcrum pressure

Assessment stroke: light

Calculus removal stroke: firm

Root surface debridement stroke: moderate

Balances of forces with instrumentation stroke: lateral pressure

Assessment stroke: feather light

Calculus Removal stroke: firm

Root surface deridement stroke: moderate

Balances of forces with instrumentation stroke: character stroke

assessment stroke: long, gliding

calculus removal stroke: short, biting

root surface debridement stroke: longer, shaving

force for calculus removal

Pinch pressure

Stabilization

Lateral pressure

pinch pressure

Pressure exerted by the fingers in the modified pen

grasp holding the instrument handle

Stabilization

the act of preparing for an instrument stroke by locking

the joints of the ring finger, then pressing the fingertip against a tooth

surface for control

fulcrum fingers

acts as a “support beam” for the hand during the

instrumentation stroke.

The hand is stabilized by pressing down with the fulcrum finger against

the tooth

lateral pressure

created by applying pressure with index finger and

thumb inward against instrument handle

Apply lateral pressure prior to and throughout instrumentation stroke