Dental Hygiene Theory 1

L1: The Dental Chair

Contoured seat
Lumbar support
Arm rests
Foot or side power controls
360-degree rotation lever or foot control
Low base

Air-water Syringe

Delivers air, water, or a mix. Available in plastic or metal.

Positioning the Operating Light

Shine on client’s chest, maintain arm’s length, follow cleaning guidelines.

Saliva Ejector

Controls moisture during procedures. Position it in a candy-cane shape under the tongue.

Instrument Cords

Types: retractable, curly, straight to manage space and prevent tangling.

Clinician's Chair

Must have a stable base with five casters, support the body, and be height adjustable.

Neutral Clinician Position

Shoulders: level
Elbows: close to body
Forearms: parallel to floor
Wrist: aligned with hands

Anatomic Descriptors

Long axis: imaginary line through center of tooth
Apical: toward root tip
Coronal: toward crown of tooth
Midline: divides tooth into halves
Line angle: intersection of two tooth surfaces
Sextant: one of six divisions of the mouth
Aspect: sextant divided into two aspects (facial and lingual).

Angles in Instrumentation

Proper angulation (45-90 degrees) vital for effective calculus removal.
Stroke direction: Use vertical, oblique, or horizontal strokes for cleaning.
Measurement tools: Periodontal probes measure anatomical features in mm.

Clinical Clock Positions

Right-handed: 8-12 o’clock
Left-handed: 4-12 o’clock
Client’s head is always at 12:00.

L2: Grasp Importance

The working end placement on instruments is crucial.
Successful instrumentation relies on modified pen grasp: precise finger placement.

Finger Identification for Grasp

Thumb and index: hold instrument
Middle finger: guides working end and feels vibrations
Ring finger: stabilizes and supports hand.

Proper Glove Fit

Important to reduce muscle strain: should be loose over the palm and wrist, well-fitted at fingertips.

Ergonomics

Study of human performance and workplace design, including environmental factors (flexibility, room temp), equipment, performance factors (wrist motion, grasp), and instrument factors (sharpness, handles).

Avoiding Musculoskeletal Problems

Work-related musculoskeletal disorders (WMD) are caused by prolonged repetitive movements, poor posture, and ill-fitting equipment. Symptoms can include loss of strength and pain.

Surgical Glove Considerations

Tight gloves can reduce blood flow and nerve function; symptoms include numbness and tingling.

L4: Dental Mirrors

Front Surface: Clear image, easily scratched.
Concave: Produces magnified image, not recommended due to distortion.
Plane: Double image, not ideal.

Stabilization of Dental Mirror

Grasp with non-dominant hand, use fingers to stabilize.

Fulcrums

Extraoral: stabilization outside the mouth.
Intraoral: stabilization on tooth surface.

Function of Dental Mirror

Indirect vision: View tooth surfaces not visible directly.
Retraction: Hold soft tissues out of the way.
Indirect illumination: Reflect light onto hidden areas.
Transillumination: Reveals carious lesions in anterior teeth.

L5: Instrument Design Significance

Instruments with ergonomic designs help prevent musculoskeletal injuries.

Handle Design: Affects prevention of injury.
Pinch Force: Should be minimal to reduce risk.

Instrument Use

Simple Shank: Anterior teeth.
Complex Shank: Posterior teeth.

Working End Parts

Face, Back, Lateral surfaces, Cutting edges, Toe/tip

L6: Fulcrum

Used to stabilize the hand during instrumentation.

Intraoral Fulcrum: In the mouth, near the tooth.
Extraoral Fulcrum: Outside the mouth, usually on chin or cheek.
Always remain 1 to 4 teeth away from the working area.

Step-by-Step Finger Rest

Assume the correct clock position
Adjust patient position
Set up equipment
Establish non-dominant hand finger rest
Grasp instrument with dominant hand
Self-check rest positioning.

Working Positions

Use palm-down for mandibular; palm-up for maxillary teeth.

Finger on finger fulcrum: Rest ring finger of dominant hand on index finger of non-dominant hand.