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FUNDAMENTALS OF PERIODONTAL INSTRUMENTATION

Comprehensive Postgraduate Teaching Notes

Source: Gehrig, Sroda & Saccuzzo - 8th Edition (ONLY)

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PART 1: ERGONOMICS AND CLINICIAN POSITIONING

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MODULE 1 - ERGONOMICS AND PERIODONTAL INSTRUMENTATION

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SECTION 1: WHAT IS ERGONOMICS?

• Definition: Ergonomics is an applied science concerned with the "fit" between people and their technological tools and environments
• Application: A discipline focused on making products and tasks comfortable and efficient for the user
• Primary principle: Equipment - such as dental instruments and workstations - should be designed to fit the user, NOT force the user to fit the equipment
• Efficiency: Ergonomics = the science of making things easier to do

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SECTION 2: MUSCULOSKELETAL DISORDERS (MSDs) IN DENTAL PROFESSIONALS

Definition

• A musculoskeletal disorder (MSD) is a condition where parts of the musculoskeletal system - muscles, tendons, nerves - are injured over time due to repeated stress
• MSDs occur when too much stress is exerted on a body part, resulting in pain from overuse
• Almost all occupations require workers to use arms and hands; therefore, most MSDs affect the hands, wrists, elbows, neck, and shoulders

Prevalence

• Many studies have investigated MSD prevalence among dental professionals
• A systemic review found that prevalence of MSDs ranged as high as 64% to 93% among dental professionals
• Despite this high prevalence, there is a lack of evidence regarding the efficacy of preventive measures for MSDs in dental hygiene
• Complete understanding of MSD progression in dental hygienists is still far from realized due to lack of longitudinal studies and standardized research techniques

Causes of MSD Pain in Periodontal Clinicians (from literature)

1. Excessive use of small hand muscles
2. Forceful repetitive motions while maintaining muscles in the same position during force application
3. Tight grips during instrumentation
4. Fixed work positions - maintaining the body in one position for extended periods

• Result: injury to the muscles, nerves, and tendon sheaths of the back, shoulders, neck, arms, elbows, wrists, and hands causing:
  • Loss of strength
  • Impairment of motor control
  • Tingling, numbness, or pain

Ergonomic Guidelines

• It is important for dental hygiene students to complete instructional modules on ergonomic principles during education and training
• Research shows that among practicing hygienists, education on patient and clinician positioning can help reduce the risk of MSDs
• It is possible to define ergonomic guidelines to minimize exposure of dental healthcare providers to musculoskeletal stress

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SECTION 3: FOUR ERGONOMIC HAZARDS IN PERIODONTAL INSTRUMENTATION

1. Awkward Postures

• Posture = the position of various parts of the body during an activity
• For most joints, ideal or neutral posture means the joint is being used near the middle of its full range of motion
• The further a joint moves away from neutral posture, the more strain is placed on the muscles, tendons, and ligaments around the joint
• Example: standing with arms outstretched vs. arms held close to body - outstretched position = high risk of injury with repetitive pulling
• Literature confirms presence of awkward postures specifically in the neck, shoulders, back, wrist, and hand in dental hygienists
• Awkward postures are adopted due to: improper adjustment of clinician's chair, improper patient position, and poor work techniques
• When dental hygienists use their bodies in awkward positions, muscles must generate higher forces than when used in a neutral position
• A common awkward posture: wrist flexion - results in stress to neurovascular structures and ligaments; poor wrist positioning can diminish grip strength
• The reduction in grip strength increases as the wrist deviates further from its neutral posture

2. Fixed Working Positions (Static Postures)

• Maintaining the body in one position for extended periods leads to muscle fatigue and injury
• Static postures restrict blood flow and cause muscle fatigue

3. Force

• Excessive force during instrumentation damages muscles, tendons, and nerves
• Tight grip forces are a primary cause of carpal tunnel syndrome

4. Repetitive Movements

• Performing the same small motions repeatedly without adequate rest leads to cumulative tissue damage
• The dental clinician performs thousands of repetitive strokes per clinical session

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SECTION 4: CARPAL TUNNEL SYNDROME AND DENTAL HYGIENE

• Among all occupations in the United States, dental hygiene ranks the highest by the Bureau of Labor Statistics in the number of carpal tunnel syndrome cases
• Risk factors for CTS in dental hygienists:
  • Repetitive forceful pinching during periodontal instrumentation
  • Sustained non-neutral wrist positions during instrumentation
• Ergonomically designed periodontal instruments may help reduce the prevalence of carpal tunnel syndrome among dental hygienists and periodontists
• The weight and diameter of instrument handles has significant effects on hand muscle load and pinch force

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SECTION 5: NEUTRAL SEATED POSITION - STEP-BY-STEP (9 Steps)

• Position the buttocks all the way back in the chair
• Distribute body weight evenly on both hips

• Adjust seat height so feet rest flat on the floor
• Establish a "wide base of support" with feet at least shoulder-width apart and in front of the hips
• Legs should NOT dangle or be crossed at the knees or ankles - dangling legs puts pressure on the back of the thighs and restricts blood flow

• Adjust the seat tilt so that the back is about an inch higher than the front (hips slightly higher than knees)
• Seat tilt should be approximately 5 degrees - helps maintain the natural lower curve of the spine and relaxes the bend of the knees
• Overtilting causes too much low back curve
• Note: Chairs without a tilt feature can be retrofitted with an ergonomic wedge-shaped cushion

• With buttocks all the way back, adjust the lumbar depth by moving the backrest closer or farther from the seat pan until it nestles against the lower back
• The unsupported lower back tends to straighten rather than maintain a healthy curve

• Adjust the lumbar height by moving the backrest up or down until it nestles in the natural lumbar curve of the lower back
• This helps to support the natural curve of the spine

• Raise the tailbone up to establish correct spinal curves
• All three normal back curves should be present while sitting
• Studies of the seated body show that the position of the pelvis determines the shape of the spine

• Stabilize the low back curve by pulling the stomach muscles toward the spine

• Relax shoulders so they are down and back
• If the stool has armrests, adjust the height so arms are supported - this helps take the weight off the shoulders

• Position upper arms parallel to the long axis of the torso with elbows held near the body
• Maintain trunk position such that an imaginary straight line connects from the ear, shoulder, and hips

Masking Tape Trick: Apply a strip of masking tape down the center of the student's back along the spinal column while in neutral position. If the clinician bends forward (out of neutral), the tape breaks - an immediate visual and tactile alert for posture correction.

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MODULE 2 - CLINICIAN POSITION IN RELATION TO THE TREATMENT AREA

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SECTION 1: CLOCK POSITIONS

• Clock positions describe the clinician's position around the dental chair relative to the patient
• For periodontal instrumentation of the anterior teeth, each tooth is divided in half at the midline

Right-Handed Clinician - Clock Positions

Maxillary vs. Mandibular Head Positions

• Mandibular arch: Chin DOWN - place the mandibular occlusal plane as parallel to the floor as possible
• Maxillary arch: Chin UP - place the maxillary occlusal plane perpendicular to the floor

Left-Handed Clinician - Special Considerations

• The 4 o'clock position should be limited since it is difficult to maintain neutral arm and torso posture in this position
• The goal is to minimize postural abnormalities whenever possible
• 3 o'clock position (to the side): Sit facing the side of the patient's head; midline of torso is even with the patient's mouth; legs may straddle the chair OR go underneath the headrest (neutral position is best achieved by straddling)
• 3-4 o'clock position (to the front): Sit facing the patient with hip in line with patient's upper arm; thighs rest against the side of the patient chair; lower left arm held over the patient's chest; the side of the right hand rests in the area of the patient's right cheekbone and upper lip - do NOT rest arm on patient's head or chest

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MODULE 3 - INSTRUMENT GRASP

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SECTION 1: PARTS OF A PERIODONTAL INSTRUMENT

• Handle: the part of a periodontal instrument used for holding the instrument
• Shank: a rod-shaped length of metal located between the handle and the working-end; generally circular, smooth, and much smaller in diameter than the handle; may be straight or bent in one or more places
• Working-End: the part of a dental instrument that does the work; begins where the instrument shank ends; may be shaped or flattened on some of its surfaces; could appear wire-like, look like a tiny ruler, or be a small mirror; a single instrument may have one or two working-ends

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SECTION 2: THE MODIFIED PEN GRASP

• The modified pen grasp is the recommended method for holding a periodontal instrument
• Facilitates:
  • Precise control of the instrument as it moves over the tooth
  • Detection of rough areas on the tooth surface (tactile sensitivity)
  • Reduced musculoskeletal stress to the clinician's fingers during instrumentation

Finger Placement - Five Key Criteria:

• Grasp the handle with the tips of the finger pads of the index finger and thumb
• These fingers must be opposite each other on the handle
• They do NOT touch or overlap each other

• Rest the pad of the middle finger lightly on the instrument shank - NOT on the handle
• The middle finger is the critical tactile finger

• Thumb, index, and middle fingers must be in a neutral joint position - no hyperextension or flexion of finger joints

• The ring finger is straight and supports the weight of the hand
• Acts as the intraoral fulcrum (finger rest) on the tooth surface
• Functions as a "support beam" for the entire hand

• Rests alongside the ring finger for additional support

Function of Each Finger in the Grasp:

• Thumb: Controls instrument; works with index finger to generate and direct force
• Index finger: Controls instrument; paired with thumb for direction and force
• Middle finger: Provides tactile information - the pad resting on the shank transmits vibrations from the tooth surface to the clinician; this is the primary sensory finger
• Ring finger: Serves as the intraoral fulcrum - the stabilization point for the hand and instrument on the tooth; provides stability for controlled, precise strokes; prevents accidental slipping that could cause tissue trauma
• Little finger: Rests beside ring finger for support

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SECTION 3: PINCH FORCE AND ERGONOMICS OF THE GRASP

• The average pinch force exerted during periodontal instrumentation is 11% to 20% of the clinician's maximum pinch strength
• Relaxing the fingers of the grasp between instrumentation strokes reduces the pinch force required
• Tight gloves increase the pinch force needed - proper glove fit is critical for preventing MSDs

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SECTION 4: JOINT HYPERMOBILITY AND THE GRASP

• Joint hypermobility: increased flexibility in the finger joints; clinicians may not know they have this condition as it is usually not disfiguring
• Problems caused by hypermobility during instrumentation:
  1. Hands are less stable; muscles have to work harder when gripping and manipulating objects
  2. Thumb or index finger joint may hyperextend (collapse inward) during the grasp
  3. Proprioceptive sensitivity may be reduced - risk of gripping with too much force
  4. Performing instrumentation with joints in a hyperextended position may cause injury by overstretching the joint
• Interventions:
  • Use of a Lycra or silicon sleeve (e.g., Silipos sleeve) can assist with proprioceptive retraining while grasping
  • A ring splint helps prevent joint hyperextension and retrains proprioceptivity of finger position (Brandfonbrener)
  • An orthopedic hand specialist should evaluate clinicians with pain/weakness due to hypermobility
  • Physical therapy and joint stabilizing devices that can be worn under surgical gloves may be helpful
  • Depending on extent of hypermobility, the clinician may need to modify the finger placement in the grasp

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MODULE 4 - USE OF THE DENTAL MOUTH MIRROR

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SECTION 1: THREE FUNCTIONS OF THE DENTAL MIRROR

1. Indirect vision: viewing tooth surfaces not directly visible (e.g., lingual surfaces, distal surfaces)
2. Transillumination: directing light onto a tooth surface for examination and detection
3. Retraction: retracting the cheek, lip, or tongue to improve access and visibility

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SECTION 2: MIRROR USE BY TREATMENT AREA

Maxillary Anteriors, Lingual Aspect - Surfaces Away:

• Sit at 11 to 1 o'clock position
• Rest the ring and little fingers of the left hand on the patient's left cheek or on the incisal edges of the maxillary anterior teeth
• Mirror head is NOT held near the maxillary anteriors - positioned closer to the tongue
• Swivel the mirror head so surfaces away from you are easily seen

Maxillary Right Posterior Sextant, Facial Aspect:

• Sit at 9 o'clock position
• Slide the mirror head between the dental arches; rest ring and little fingers on right side of patient's face
• Retract the buccal mucosa with the mirror
• Use mirror for indirect vision, particularly to view distal surfaces
• Swivel the mirror head until distal surfaces are easily viewed in the reflecting surface

Mandibular Anteriors, Lingual Aspect - Surfaces Toward:

• Sit at 11 to 1 o'clock position
• Rest ring and little fingers on the right side of the patient's face near the corner of the mouth or on one of the premolar teeth
• Use the mirror head to gently push the tongue back so lingual surfaces of the teeth can be seen

Mandibular Left Posterior Sextant, Facial Aspect:

• Sit at 3 o'clock position
• Rest fingers on the left side of the patient's face
• Retract the buccal mucosa with the mirror
• Use mirror for indirect vision, particularly to view distal surfaces

Mandibular Right Posterior Sextant, Lingual Aspect:

• Sit at 3 o'clock position
• Rest fingers on the left side of the patient's face
• Use mirror to gently move the tongue away from the teeth, toward the midline of the mouth
• Use indirect vision to view distal and lingual surfaces
• Tip: Avoid pressing down against the floor of the mouth with the mirror head

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SECTION 3: MIRROR TECHNIQUE DETAILS - IMPORTANT RULES

• Posterior retraction: Position the mirror by turning the handle until the mirror head is parallel to the buccal mucosa; the back of the mirror head rests against the buccal mucosa; the reflecting surface faces the facial surfaces
• Establish an extraoral finger rest on the side of the patient's cheek during retraction
• Use arm muscles for retraction - pulling with only finger muscles is difficult and tiring
• AVOID hitting the mirror head against the patient's teeth
• AVOID resting the outer rim of the mirror head against the patient's gingival tissues
• AVOID resting the edge of the mirror head against the alveolar process (mandibular facial aspects)
• Do NOT use the instrument shank for retraction - will be uncomfortable for the patient

Anti-Fogging Techniques for the Mirror:

• Warm the reflecting surface against the patient's buccal mucosa before use
• Ask patient to breathe through the nose
• Wipe the reflecting surface with a commercial de-fogging solution
• Wipe the reflecting surface with a gauze square moistened with mouthwash

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MODULES 5, 6, 7 - FINGER RESTS (ANTERIOR AND POSTERIOR SEXTANTS)

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SECTION 1: PRINCIPLES OF THE INTRAORAL FINGER REST (FULCRUM)

• The finger rest (intraoral fulcrum) is established with the ring finger of the instrument hand
• The ring finger must be straight when establishing a finger rest
• Purpose:
  • Provides stability for controlled, precise instrument strokes
  • Prevents accidental slipping that could cause soft tissue trauma
  • Serves as a pivot-point for wrist-rocking motion activation
  • Acts as a "brake" to stop movement at the end of each stroke - if the instrument tip flies off the tooth at end of a stroke, the clinician did not stop the stroke by pressing down with the fulcrum

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SECTION 2: HANDLE POSITIONS

For Mandibular Treatment Areas:

1. Hold the hand in a palm-down position
2. Rest the handle against the index finger in the designated handle resting zone

For Maxillary Treatment Areas:

1. Hold the hand in a palm-up position
2. Rest the handle against the index finger in the designated handle resting zone

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SECTION 3: FINGER RESTS - ANTERIOR SEXTANTS (MODULE 5)

Mandibular Anteriors, Facial Aspect - Surfaces TOWARD:

• Retract the lip with the index finger or thumb of the non-dominant hand
• Task 1 (Mesial of left canine): Finger rest on an occlusofacial line angle
• Task 2 (Distal of right canine): Finger rest on an incisal edge

Mandibular Anteriors, Lingual Aspect - Surfaces TOWARD:

• Task 1 (Mesial of left canine): Finger rest on an occlusofacial line angle

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SECTION 4: FINGER RESTS - MANDIBULAR POSTERIOR SEXTANTS (MODULE 6)

Mandibular Left Posterior Sextant, Facial Aspect:

• Use mirror to retract buccal mucosa; use for indirect vision (especially distal surfaces)
• Tip: Avoid resting the edge of the mirror head against the alveolar process
• Task 1 (Second molar, facial): Finger rest on occlusal surface
• Task 2 (First premolar, facial): Finger rest on incisal surface of a mandibular anterior tooth

Mandibular Left Posterior Sextant, Lingual Aspect:

• Use mirror to gently move the tongue away from the teeth
• Tip: Avoid pressing down against the floor of the mouth with the mirror head
• Task 1 (Second molar, lingual): Finger rest on occlusofacial line angle
• Task 2 (First premolar, lingual): Finger rest on an incisal edge of a mandibular anterior tooth

Mandibular Posterior - Aspects Facing AWAY From the Clinician:

• Clinician moves to 11-12 o'clock clock position
• Handle positions change accordingly (palm-up vs. palm-down must be correctly applied)

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SECTION 5: FINGER RESTS - MAXILLARY POSTERIOR SEXTANTS (MODULE 7)

Maxillary Left Posterior Sextant, Facial Aspect (Left-Handed Clinician):

• Clinician clock position: 3 o'clock; patient head position: chin-UP
• Hold the hand in a palm-up position
• Task 1 (Second molar, facial): Finger rest on occlusal surface
• Use mirror to retract the buccal mucosa; use for indirect vision of distal surfaces

Maxillary Posterior - Aspects Facing AWAY From Clinician:

• Clinician clock position: 11-12 o'clock; patient head position: chin-UP
• Handle resting zone and palm position adjust accordingly

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PART 2: INSTRUMENT DESIGN AND TECHNIQUE ESSENTIALS

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MODULE 8 - INSTRUMENT DESIGN AND CLASSIFICATION

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SECTION 1: HANDLE DESIGN - THE SIGNIFICANCE

Carpal Tunnel Syndrome (CTS) and Dental Hygiene

• Dental hygiene ranks highest among all US occupations in number of CTS cases (Bureau of Labor Statistics)
• Risk factors for CTS:
  • Repetitive forceful pinching during periodontal instrumentation
  • Sustained non-neutral wrist positions

Pinch Force in the Grasp

• Average pinch force during instrumentation = 11% to 20% of the clinician's maximum pinch strength
• Relaxing the fingers between strokes reduces pinch force

Handle Selection Criteria (Table 8-1 from textbook):

1. Instrument Weight (≤15 g):
   • Lightweight instruments (15 g or less) are optimal for periodontal instrumentation
   • Lightweight instruments place less stress on the muscles of the hand
   • Periodontal instruments with heavier weight handles are associated with greater muscle activity
2. Handle Diameter (10 mm):
   • Larger diameter handles reduce the pinch force required significantly
   • Small diameter handles force the clinician to pinch harder to maintain control
3. Taper Near Shank:
   • Allows the clinician's fingers to be closer to the working-end
   • Increases proprioceptive feedback and instrument control
4. Raised Texturing:
   • Allows secure grip at lower pinch forces compared to smooth handles
   • Non-raised texturing provides little friction benefit

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SECTION 2: SHANK DESIGN

• Shank connects the handle to the working-end; transmits forces from the hand to the working-end
• The shank may be straight or bent in one or more places

Lower Shank (Terminal Shank)

• The portion of the shank closest to the working-end
• Used as a reference for angulation - the relationship of the lower shank to the tooth surface indicates correct instrument positioning
• For correct subgingival curet placement: lower shank should be parallel to the long axis of the root surface being instrumented

Shank Angulation and Access

• Straight shank: for anterior teeth and some premolars (simple shank design)
• Angled/curved shank: for posterior teeth (complex shank design - bent in one or more places)
• Extended shank (e.g., Gracey extended shank curets): 3 mm longer than standard shank; provides better access to deep periodontal pockets

Shank Flexibility

• Flexible/thin shank: better tactile sensitivity; ideal for lighter deposit removal, assessment, and root debridement
• Rigid/thick shank: for heavier, tenacious calculus removal; provides greater lateral force transmission

Simple vs. Complex Shanks (Instrument Classification)

• Simple shank (one bend or straight): best for anterior teeth and some premolars
• Complex shank (multiple bends): designed for access to posterior teeth; the bends offset the working-end so it can reach all surfaces of posterior teeth

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SECTION 3: WORKING-END DESIGN AND CLASSIFICATION

Assessment Instruments

• Purpose: Detection of tooth surface irregularities, calculus, and caries
• Design: Pointed or fine working-end; wire-like appearance
• Examples: periodontal probe, explorer

Calculus Removal Instruments

• Purpose: Removal of calculus deposits supragingival and subgingival
• Design: Working-end with one or two cutting edges
• Examples: sickle scalers, curets

Classification of Calculus Removal Instruments:

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MODULE 9 - TECHNIQUE ESSENTIALS: MOVEMENT AND ORIENTATION TO TOOTH SURFACE

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SECTION 1: MOTION ACTIVATION - TWO TYPES

1. Wrist-Rocking Motion Activation (RECOMMENDED for calculus removal)

• Definition: Wrist-rocking motion activation is the act of rotating the hand and wrist as a unit to provide the power for an instrumentation stroke
• Movement is a rotating motion similar to turning a doorknob
• This technique allows the clinician to maintain neutral upper body posture - shoulders level, upper arm vertical, forearm horizontal
• Keeps the workload on the forearm and wrist rather than on the hand and fingers
• A clinician experiences less fatigue using wrist-rocking motion than if finger movements are used
• Wrist-rocking motion is recommended for calculus removal with hand-activated instruments

• During motion activation, the fulcrum finger supports the weight of the hand and assists in controlling the movement of the working-end
• Throughout the production of an instrument stroke, the fulcrum finger should remain pressed against the tooth to act as a pivot-point for the motion
• The slight pressure of the finger against the tooth allows the fulcrum to act like a "brake" to stop the movement at the end of each stroke
• If the instrument tip flies off the tooth at the end of a stroke, the clinician did not stop the stroke by pressing down with the fulcrum

2. Digital (Finger) Activation

• Definition: Digital motion activation - finger activation - moves the instrument by making push-pull movements with the thumb, index, and middle fingers
• Example (mandibular teeth): fingers are used to pull the working-end up the tooth, then a push movement returns the working-end to its starting position
• Digital motion is used when physical strength is not required during instrumentation
• Most commonly used with powered instruments (ultrasonic and sonic) - with powered instruments, the machine provides force for calculus removal
• Also used to instrument areas of very restricted movement, such as furcation areas

Stroke Length

• Instrumentation strokes are tiny movements - the working-end is moved only a few millimeters with each stroke

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SECTION 2: ANGULATION - ORIENTATION TO TOOTH SURFACE

• Angulation = the angle formed between the face of the working-end and the tooth surface
• Correct angulation for calculus removal: 70 to 80 degrees (face of working-end to tooth surface)

Consequences of Incorrect Angulation:

• 0 degrees (face flat against tooth, too closed): no cutting action; the cutting edge cannot engage calculus
• 45 degrees: beginning of calculus removal; acceptable for some situations
• 90 degrees (face perpendicular to tooth, too open): causes tissue trauma; working-end will lacerate the gingival tissue
• The 70-80 degree range is optimal - allows the cutting edge to engage and remove calculus without causing tissue trauma

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MODULE 10 - TECHNIQUE ESSENTIALS: ADAPTATION

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SECTION 1: DEFINITION OF ADAPTATION

• Adaptation refers to the positioning of the first 1 to 2 mm (the leading-third) of the working-end's lateral surface in contact with the tooth
• For successful instrumentation, correct adaptation must be maintained as the working-end is moved over the tooth surface
• Adaptation applies to both sickle scalers and curets

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SECTION 2: LEADING-THIRD / TOE-THIRD OF THE WORKING-END

Parts of the Cutting Edge:

• The cutting edge is divided into thirds:
  • Toe-third (curet) / Tip-third (sickle scaler): the leading portion - first 1-2 mm
  • Middle-third: the central portion
  • Heel-third: the trailing portion closest to the shank

Correct Adaptation Rule:

• ONLY the toe-third (or tip-third) of the cutting edge should contact the tooth surface
• Use of the middle or heel-third against the tooth is incorrect and may cause trauma to the tissue of the interdental papilla
• Especially critical with anterior teeth since these teeth are narrow in width (mesial to distal measurement) - in most cases, only the tip-third can be adapted to the curved tooth surface

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SECTION 3: ERGONOMICS OF THE HANDLE ROLL FOR ADAPTATION

• As the instrument moves around curved surfaces (e.g., line angles), the handle must be rolled between the finger pads to maintain the toe-third against the tooth
• How to perform the handle roll:
  • Roll the handle using the pads of the thumb and index finger
  • The roll is a small, controlled rotation
  • Ensures continuous adaptation around line angles without breaking contact with the tooth surface
• Maintaining adaptation to the tip-third of the working-end, the midline of a tooth, and line angles requires this continuous handle rolling

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SECTION 4: SELECTING THE CORRECT WORKING-END

• For double-ended instruments: selecting the correct working-end ensures proper adaptation and angulation
• Test for correct working-end: when properly adapted, the lower shank should be parallel to the long axis of the tooth (or the surface being instrumented)
• This test applies primarily to curets; with the correct working-end selected, the face of the curet will automatically achieve the correct 70-80 degree angulation when the lower shank is parallel to the root surface

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MODULE 11 - TECHNIQUE ESSENTIALS: INSTRUMENTATION STROKES

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SECTION 1: CHARACTERISTICS OF THE INSTRUMENTATION STROKE

• An instrumentation stroke is a controlled movement of the instrument working-end across a tooth surface

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SECTION 2: THREE STROKE DIRECTIONS

1. Vertical strokes: working-end moves parallel to the long axis of the tooth (coronally to apically or vice versa)
2. Oblique strokes: working-end moves at a diagonal angle to the long axis - most commonly used in clinical practice
3. Horizontal strokes: working-end moves perpendicular to the long axis (parallel to the gingival margin); used in areas of limited access, such as furcation areas and the midlines of anterior teeth
4. Multidirectional strokes: combination of vertical, oblique, and horizontal strokes - used to ensure complete root surface coverage

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SECTION 3: THREE TYPES OF INSTRUMENTATION STROKES - DETAILED

1. Assessment Stroke

• Purpose: Detect calculus deposits, tooth surface irregularities, caries
• Angulation: Near-closed angle (close to 0 degrees) - the face hugs the tooth surface
• Pressure: Light (featherlight) - detection mode, not removal mode
• Length: Long, overlapping, sweeping strokes to map the entire root surface
• Motion: Gentle, exploratory
• Tactile information is transmitted through the middle finger resting on the shank

2. Calculus Removal Stroke

• Purpose: Physically remove calculus deposits from the tooth surface
• Angulation: 70-80 degrees - face opened to engage the cutting edge
• Pressure: Firm lateral pressure
• Length: Short and biting - each stroke lifts/snaps the deposit from the tooth
• Key rules:
  • Each stroke is distinct - make only ONE short stroke, then stop
  • Do NOT make a series of continuous back-and-forth strokes
  • End each stroke with precision by pressing down with the fulcrum finger against the occlusolingual line angle of the crown
  • After each stroke: pause for at least 3 seconds to relax hand muscles and prevent strain
  • Count "1-one thousand, 2-one thousand, 3-one thousand" to ensure muscle relaxation between strokes
  • Keep the working-end beneath the gingival margin between strokes (do NOT remove from the pocket with each stroke to avoid trauma to the gingival margin)

Flow Chart for Calculus Removal Stroke Sequence:

1. GET READY: Place working-end in middle-third of tooth surface
2. INSERT CURET WORKING-END: Hug face against tooth surface and slide beneath gingival margin
3. ASSESS: Use assessment stroke to locate calculus deposit
4. POSITION WORKING-END: Position just apical to calculus deposit
5. CUP THE WORKING-END: Cup the calculus deposit with the curet
6. LOCK THE TOE-THIRD AND OPEN THE FACE: Lock toe-third of cutting edge against root surface; apply inward pressure against handle with index finger and thumb; establish correct angulation by opening the face to 80 degrees
7. ACTIVATE CALCULUS REMOVAL STROKE: Keep the toe-third locked against root surface; make a short, biting stroke AWAY from the junctional epithelium (coronally)
8. END STROKE AND RELAX: End each stroke with precision; pause; relax grasp for at least 3 seconds; do NOT close face toward tooth surface during activation

3. Root Surface Debridement Stroke

• Purpose: Smooth the root surface; remove residual calculus deposits; create a biocompatible root surface
• Goal: "Out-of-the-groove-free" root surface - removing residual deposits from grooves and concavities
• Angulation: 70-80 degrees (same as calculus removal) but...
• Pressure: Light to moderate
• Length: Overlapping, multidirectional strokes covering every millimeter of the root surface
• Ensures complete coverage from the gingival margin to the base of the pocket (junctional epithelium)

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SECTION 4: ERGONOMICS OF STROKE PRESSURE

• Tailoring pressure to the task:
  • Assessment: light pressure
  • Calculus removal: firm lateral pressure
  • Root debridement: light to moderate pressure
• Use the ring finger (fulcrum) as the "support beam" for the hand during all strokes
• Stabilize the hand and instrument using the intraoral fulcrum before applying pressure
• Strategies for Avoiding Injury During Instrumentation:
  • Make only one short stroke, then stop and relax fingers
  • Do NOT make a series of continuous back-and-forth strokes
  • Pause at least 3 seconds between strokes
  • Use wrist-rocking motion (NOT finger-only activation) for calculus removal
  • Maintain neutral wrist position throughout motion activation

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PART 3: PERIODONTAL PROBES, PROBING TECHNIQUE, AND EXPLORERS

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MODULE 12 - PERIODONTAL PROBES AND BASIC PROBING TECHNIQUE

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SECTION 1: THE PERIODONTAL PROBE - FUNCTION AND PURPOSE

Functions of the Periodontal Probe:

• Assess the health of the gingival tissues
• Measure the depth of the sulcus or periodontal pocket
• Detect bleeding on probing (an indicator of gingival inflammation)
• Detect calculus deposits subgingivally
• Measure the size of intraoral lesions
• Determine mucogingival relationships (position of the mucogingival junction)
• Monitor the longitudinal response of the periodontium to treatment over time

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SECTION 2: PROBE DESIGNS (Table 12-1 from textbook)

• Tip diameters range from 0.28 mm (Michigan "O") to 0.7 mm (Williams probe)
• Most periodontal probes are made of stainless steel; some are titanium or plastic

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SECTION 3: ASSESSING TISSUE HEALTH

Clinical Signs to Assess:

• Color: healthy gingiva = pink (or consistent with patient's melanin pigmentation); unhealthy = red or reddish-blue
• Contour: healthy gingiva has knife-edged margins and pointed papillae
• Consistency/Texture: healthy gingiva = firm, stippled (orange-peel texture); inflamed = soft, edematous, smooth and shiny
• Bleeding on probing: presence of bleeding indicates active inflammation (junctional epithelium is ulcerated in inflamed tissue)

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SECTION 4: READING AND RECORDING MEASUREMENTS

Probing Depth vs. Clinical Attachment Level (CAL)

• Probing Depth: distance from the free gingival margin to the base of the sulcus/pocket (the junctional epithelium)
• Clinical Attachment Level (CAL): distance from the cementoenamel junction (CEJ) to the base of the sulcus/pocket
• CAL = Probing Depth + (measurement from CEJ to gingival margin, with sign convention)

Sign Convention for Gingival Margin Position:

• Zero (0): gingival margin is at the level of the CEJ
• Negative (-): gingival margin is coronal to the CEJ (covers the CEJ) - this occurs with gingival enlargement
• Positive (+): gingival margin is apical to (below) the CEJ - this occurs with gingival recession

Calculating Clinical Attachment Level:

• If gingival margin is at the CEJ: CAL = probing depth
• If gingival margin is coronal to the CEJ: CAL = probing depth minus the distance the gingival margin is above the CEJ
• If gingival margin is apical to the CEJ: CAL = probing depth plus the distance the gingival margin is below the CEJ

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SECTION 5: PROBING TECHNIQUE - THE WALKING STROKE (Zone-by-Zone)

Key Concept - "Walking Stroke"

• The probe is walked around the tooth using a series of short, bobbing strokes - each stroke approximately 1 mm
• Gently touch the junctional epithelium with each downward stroke
• Strokes are kept close together - the probe "walks" from one zone to the next

Three Zones Per Tooth (Facial Aspect Example - First Molar):

1. Position the probe at the distofacial line angle in the get-ready zone (middle-third of crown, just forward of the distofacial line angle; tip aims toward the back of the mouth)
2. Initiate a series of short, bobbing strokes toward the distal surface
3. Walk the probe across the distal surface until it touches the contact area
4. Tilt the probe so the tip reaches beneath the contact area (upper portion of probe touches the contact area); gently press downward to touch the junctional epithelium
5. Enter the deepest reading encountered for Zone 1 (distal area 1) on the periodontal chart

1. Reposition the probe at the distofacial line angle
2. Make a series of tiny walking strokes across the facial surface - moving in a forward direction toward the mesiofacial line angle
3. Record the deepest measurement for Area 2 (facial) on the chart

1. Walk the probe from the mesiofacial line angle across the mesial surface until it touches the contact area
2. Tilt the probe and extend the tip beneath the contact area; press down gently to touch the junctional epithelium
3. Record the deepest reading for Zone 3 (mesial area from facial) on the chart

Important: Use the same zone-by-zone walking technique for the lingual aspect, completing the remaining three zones from the lingual.

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SECTION 6: CALCULATING WIDTH OF ATTACHED GINGIVA

Definition of Attached Gingiva:

• The attached gingiva is the part of the gingiva tightly connected to the cementum on the cervical third of the root or to the periosteum (connective tissue cover) of the alveolar bone
• Lies between the free gingiva and the alveolar mucosa
• Extends from the base of the sulcus or pocket to the mucogingival junction
• The alveolar mucosa is detected visually by its deep red color and shiny appearance

Functions of the Attached Gingiva:

1. Keep the free gingiva from being pulled away from the tooth
2. Protect the gingiva from trauma

Important Notes:

• Width of the attached gingiva is NOT measured on the palate - it is not possible to determine where attached gingiva ends and palatal mucosa begins
• Attached gingiva does NOT include any portion of the gingiva that is separated from the tooth

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MODULE 13 - EXPLORERS

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SECTION 1: EXPLORERS - PURPOSE AND DESIGN

• Explorer: an assessment instrument used to detect calculus deposits, tooth surface irregularities, and dental caries by tactile perception (sense of touch through vibrations transmitted via the shank to the clinician's fingers)
• The explorer tip is wire-like and very fine
• Used subgingivally and supragingival

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SECTION 2: TECHNIQUE PRACTICE - POSTERIOR TEETH (Mandibular First Molar Example)

• Place the tip in the middle-third of the crown just forward of the distofacial line angle
• The tip should aim toward the back of the mouth (direction of work)

• Lower the instrument hand
• Adapt the "face" of the explorer tip to the tooth surface
• Slide the tip beneath the gingival margin

• Return the handle to its normal position
• Beginning at the distofacial line angle, make featherlight strokes toward the distal surface

• Roll the instrument handle slightly to adapt to the distal surface
• Explore at least halfway across the distal surface from the facial aspect
• Keep the tip adapted to the tooth surface at all times

• Reposition the tip for the facial surface: remove tip from the sulcus and turn it so it aims toward the front of the mouth; place tip in the middle-third of the facial surface with the point facing forward
• Lower the handle and insert - place the "face" of the explorer against the facial surface; reinsert tip just to the left of the distofacial line angle
• Return the handle to its normal position; beginning at the distofacial line angle, explore the facial surface moving toward the mesiofacial line angle

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SECTION 3: DETECTION OF DENTAL CALCULUS - TACTILE DESCRIPTION

• Calculus is detected as a rough, nodular, or ledge-like irregularity on the tooth surface
• Transmitted as a grating, bumpy sensation through the explorer to the clinician's fingers
• Calculus can be:
  • Supragingival: visible and/or detectable
  • Subgingival: detected ONLY by tactile exploration (cannot be seen)

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SECTION 4: DETECTION OF DENTAL CARIES

• Carious lesions are detected as a soft, sticky, or catch sensation under the explorer tip
• The explorer tip may stick in a carious lesion as opposed to sliding smoothly over a healthy surface
• Important: use caution with explorer force on suspected carious lesions - excessive force can damage demineralized enamel

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MODULE 18 - ADVANCED PROBING TECHNIQUES

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SECTION 1: CLINICAL ATTACHMENT LEVEL MEASUREMENT

• Clinical Attachment Level (CAL) provides a more accurate picture of periodontal disease severity than probing depth alone
• CAL indicates how much periodontal support has been lost from around the tooth
• Probing depth alone does not tell us whether attachment loss has occurred (a 4 mm pocket with the gingival margin at the CEJ means 4 mm of attachment loss; a 4 mm pocket with the margin 2 mm below the CEJ means 6 mm of attachment loss)

Periodontal Chart Documentation:

1. Probing depth measurements (GM to base of pocket)
2. Measurement of gingival margin to CEJ (GM to CEJ)
3. Calculated clinical attachment levels

Sample Chart Interpretation:

• Tooth 28: gingival margin is at the level of the CEJ on facial and lingual → zero noted
• Teeth 25-27: gingival margin covers the CEJ → negative sign (-) indicates margin is coronal to CEJ
• Teeth 29 and 31: gingival margin is apical to (below) the CEJ → positive sign (+) indicates recession

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SECTION 2: MUCOGINGIVAL RELATIONSHIPS

• Mucogingival junction (MGJ): the boundary between the attached gingiva and the alveolar mucosa
• Measured to determine width of attached gingiva
• Width of attached gingiva = total gingival width minus the probing depth
• NOT measured on the palate (cannot distinguish attached gingiva from palatal mucosa)

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PART 4: CALCULUS REMOVAL AND CURETS

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MODULE 14 - TECHNIQUE ESSENTIALS: SUPRAGINGIVAL CALCULUS REMOVAL

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SECTION 1: SUPRAGINGIVAL CALCULUS DEPOSITS

• Supragingival calculus is located above the gingival margin - visible to direct or indirect vision
• Also called salivary calculus (white or creamy yellow; associated with salivary duct openings)
• Usually lighter, more brittle than subgingival calculus
• Found most commonly on the lingual surfaces of mandibular anteriors (near submandibular and sublingual ducts) and facial surfaces of maxillary molars (near Stenson's duct)

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SECTION 2: RELATIONSHIP OF INSTRUMENT FACE TO TOOTH SURFACE

• For supragingival calculus removal: use an angulation of 70-80 degrees
• The face of the working-end must be opened appropriately to engage the calculus
• Too closed (0-45 degrees): burnishes the calculus rather than removing it
• Too open (90 degrees): causes tissue trauma, instrument slips

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SECTION 3: APPLICATION OF FORCE FOR CALCULUS REMOVAL

• Force is applied by:
  1. Pressing the cutting edge against the calculus deposit
  2. Using the wrist-rocking motion to activate the stroke
  3. The ring finger (fulcrum) acts as the pivot point and controls force
• The lateral pressure against the tooth is maintained throughout the stroke
• Force should be directed away from the junctional epithelium (coronally)

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SECTION 4: STROKE PATTERN FOR SUPRAGINGIVAL CALCULUS REMOVAL

• Use overlapping vertical, oblique, and horizontal strokes to ensure complete removal
• Each area should be approached from multiple directions
• Begin at the gingival margin and work coronally
• Horizontal strokes are used for calculus at the midlines of anterior teeth and in furcation areas

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MODULE 15 - SICKLE SCALERS

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SECTION 1: SICKLE SCALER - DESIGN CHARACTERISTICS

• Sickle scaler: a hand-activated calculus removal instrument with two cutting edges and a pointed tip
• Cross-section: triangular
• The pointed tip means the sickle scaler cannot be inserted deep into the sulcus without risking tissue trauma - this limits its use to supragingival and superficial subgingival areas only

Types of Sickle Scalers:

1. Anterior sickle scaler: straight or slightly curved design for anterior teeth; working-end is in line with the handle or at a slight angle
2. Posterior sickle scaler: has a curved or angled shank for access to posterior teeth; has an outer cutting edge (used on the tooth surface facing away from the clinician) and an inner cutting edge (used on the tooth surface facing toward the clinician)

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SECTION 2: USES AND LIMITATIONS OF SICKLE SCALERS

• Removal of supragingival calculus on all teeth
• Removal of superficial subgingival calculus (just below the gingival margin)

• The pointed tip prevents safe insertion to the base of deep pockets
• Cannot be used for thorough root debridement in deeper pockets
• Risk of tissue trauma if inserted too deeply

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SECTION 3: CALCULUS REMOVAL CONCEPTS

• Working-end must be tilted slightly toward the tooth surface to obtain correct angulation (70-80 degrees)
• The lower shank should be parallel or tilted slightly toward the tooth surface being instrumented
• The outer cutting edge of a posterior sickle scaler is used on the distal surfaces facing away from the clinician
• The inner cutting edge is used on surfaces facing toward the clinician

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SECTION 4: MAINTAINING ADAPTATION TO PROXIMAL SURFACES

Skill 1 - Adapting the Tip-Third to the Midline of a Tooth

• Tooth surfaces are curved - only the tip-third of the cutting edge can be adapted to the surface (especially with anterior teeth, which are narrow mesial-to-distally)
• Using the middle-third of the cutting edge on the mesial surface might result in trauma to the tissue of the interdental papilla
• Continue strokes until working at least halfway across the mesial surface from the facial aspect - the other half of the mesial surface is instrumented from the lingual aspect

Angulation Check for Sickle Scaler:

• Correct angulation = 70 to 80 degrees
• Keep the tip-third of the cutting edge adapted to the mesial surface throughout

Sequence for Anterior Teeth (Facial Aspect Example):

• Begin with the left canine and end with the right canine (one direction)
• Change clock position and complete the remaining facial surfaces, beginning with the right canine and ending with the left canine

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SECTION 5: TECHNIQUE PRACTICE - POSTERIOR TEETH WITH SICKLE SCALER

• Identify the correct working-end of the posterior sickle scaler using visual cues
• Demonstrate correct adaptation and angulation on the posterior teeth
• Explain why the lower shank must be tilted slightly toward the tooth surface to obtain correct angulation
• Demonstrate three skills used to maintain adaptation to the proximal surfaces of posterior teeth

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SECTION 6: RECIPE FOR ARTIFICIAL DENTAL CALCULUS (Practice Aid)

• Plaster of Paris + oil-based paint (for color) + texture additive + shellac or paint
• Combine 1 teaspoon of each ingredient to create enough for one typodont
• Apply immediately and allow artificial calculus to dry overnight

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MODULE 16 - TECHNIQUE ESSENTIALS: SUBGINGIVAL CALCULUS REMOVAL

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SECTION 1: THE SENSE OF TOUCH FOR SUBGINGIVAL INSTRUMENTATION

• Subgingival calculus CANNOT be seen - must be detected by tactile sense
• Tactile information is transmitted through the instrument shank to the middle finger resting lightly on the shank
• Characteristics of subgingival calculus:
  • Often harder and darker than supragingival calculus (burnite/dark brown calculus - associated with crevicular fluid)
  • May be calcified in thin sheets or ledges that are difficult to detect
  • May be in grooves or root concavities

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SECTION 2: INSERTING A CURET BENEATH THE GINGIVAL MARGIN

Subgingival Calculus Removal Technique - Key Steps:

• Place the working-end in the middle-third of the tooth surface

• Hug the face of the curet against the tooth surface (closed angulation, near 0 degrees)
• Gently slide the working-end beneath the gingival margin and down to the base of the sulcus or pocket
• Gentle insertion prevents trauma to the sulcular epithelium

• Use assessment stroke to locate the calculus deposit with light, sweeping strokes away from the junctional epithelium

• Position the working-end just apical to the calculus deposit

• Lock the toe-third of the cutting edge against the root surface
• Apply inward pressure against the handle with the index finger and thumb
• Open the face to 80 degrees
• Make a short, biting stroke in a coronal direction (away from the junctional epithelium) to snap/lift the deposit from the tooth
• Use a rotating (wrist-rocking) motion - use the whole hand as a unit; do NOT pull with thumb and index finger alone
• Maintain appropriate lateral pressure against the tooth throughout the stroke while maintaining control of the working-end

• Precisely stop each individual stroke
• Pause briefly (at least 3 seconds) to relax the grasp before repositioning the working-end beneath the calculus deposit
• Strokes should be short and working-end remains beneath the gingival margin (to avoid trauma to the gingival margin) - do NOT remove the working-end from the pocket with each stroke
• Maintain neutral wrist position throughout motion activation

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MODULE 17 - UNIVERSAL CURETS

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SECTION 1: UNIVERSAL CURET - DESIGN CHARACTERISTICS

• A universal curet is a hand-activated subgingival instrument with:
  • Two cutting edges on the working-end
  • A rounded toe (not pointed - allows safe insertion to the base of deep pockets)
  • Cross-section: half-moon (semi-circular)
  • The face of the working-end is perpendicular to the terminal shank (at 90 degrees)
• The term "universal" means it can be adapted to all tooth surfaces (anterior and posterior; all aspects)
• Can be used on any tooth in the mouth using the same set of working-ends (with appropriate technique adaptation)

Curet vs. Sickle Scaler:

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SECTION 2: UNIVERSAL CURET - CLINICAL USE

• Can be adapted to all tooth surfaces including: facial, lingual, mesial, distal aspects; anterior and posterior teeth; maxillary and mandibular arches
• Two cutting edges: one for surfaces facing toward the clinician and one for surfaces facing away
• The clinician selects which cutting edge to use based on the surface being instrumented

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MODULE 19 - AREA-SPECIFIC CURETS (GRACEY CURETS)

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SECTION 1: AREA-SPECIFIC CURETS - DESIGN CHARACTERISTICS

• Area-specific curets: designed to be used on specific tooth surfaces or areas of the mouth
• Most common: Gracey curets (designed by Dr. Clayton Gracey)
• Design features:
  • One cutting edge (the lower, outer edge)
  • Rounded toe
  • Offset blade: the face of the working-end is offset (angled) from the terminal shank at approximately 70 degrees (rather than 90 degrees as in universal curets)
  • The lower (outer) cutting edge is the working cutting edge

Why the Offset Blade is Significant:

• When the lower shank is parallel to the root surface, the offset blade automatically positions the working face at the correct 70-degree angulation to the tooth
• This makes correct angulation easier to achieve with Gracey curets compared to universal curets
• The 70-degree offset of the face ensures correct angulation WITHOUT the clinician having to consciously calculate angulation

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SECTION 2: GRACEY CURET NUMBERING SYSTEM

• Gracey curets are double-ended - each number pair (e.g., 11-12) works as a pair, one for each arch or orientation

Extended Shank Gracey Curets (After Five Curets):

• Shank is 3 mm longer than standard Gracey curets
• Provides access to deep periodontal pockets (greater than 5 mm)
• Used in combination with advanced extraoral fulcruming techniques

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SECTION 3: SELECTING THE CORRECT WORKING-END - GRACEY CURETS

• Lower cutting edge test: when the working-end is correctly positioned against the tooth with the lower shank parallel to the root surface, the lower (outer) cutting edge engages the tooth while the upper (inner) edge is away from the tooth
• For a Gracey 11-12: the working-end designed for the mesial surfaces of mandibular posteriors is selected by ensuring the face opens toward the tooth surface and the lower shank is parallel to the mesial surface

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• Advanced Probing Techniques (detailed CAL measurement, furcation classification, mobility assessment)
• Advanced Root Instrumentation (extraoral fulcrums, deep pockets, furcation instrumentation)
• Instrument Sharpening (principles, stone technique, testing sharpness)
• Powered Instruments (ultrasonic and sonic; tip designs; technique)
• Air Polishing (biofilm management; technique)