DH101 Preclinical SciencesErgonomics

Nield Book CH 1&2Wilkins CH7

Lisa Mayo, RDH, BSDHStaci Janous, RDH, BS

Concorde Career College

Topics To Cover Today

1. Principles of Ergonomics2. Positioning of Clinician (neutral position,

stool)3. Patient Positioning4. Light & Instrument Tray5. Clock Positions6. How To Prevent Injury

OBJECTIVE #1Principles of Ergonomics

Copyright © 2010 by Saunders, an imprint of Elsevier Inc.

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Principles of Ergonomics

◦Musculoskeletal disorder: condition where parts of the musculoskeletal system (tendons, nerves, muscles) are injured over time

◦Major issues in dentistry due to:1) Fixed/Static working positions2) Excessive use of small muscles3) Tight grips4) Repetitive movements5) Positioning challenges6) Confined working spaces

Nield p.5

Copyright © 2010 by Saunders, an imprint of Elsevier Inc.

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Principles of Ergonomics

◦Musculoskeletal disorder prevention: ERGONOMICS Applied science concerning the “fit” between people &

their technology Science of making things efficient Ergonomic guidelines exist for dental professionals

Nield p.5

OBJECTIVE #2Positioning of Clinician

Neutral Working Posture

Neutral Working Position◦Whole body functional biomechanics as it

relates to all work activities ◦Without will experience discomfort, pain, and

work-related stress disorders

Nield p.10-12

Neutral Working Posture

Neutral Seated Position◦Neck◦Back◦Torso◦Shoulders◦Upper Arm◦Forearm◦Hand◦Feet Nield p.10-12

What NOT to do!!

Neutral Seated PositionNECK

◦Head tilt 0-20°◦Line from eyes to treatment area vertical as

possible

BACK◦Lean forward slightly from the hips◦Trunk flexion 0-20°

Neutral Seated Position

TORSO◦In line with long axis of body◦Do NOT twist or lean torso

Neutral Seated Position

SHOULDERS◦In HORIZONTAL LINE◦Weight evenly balance when seated◦Do NOT lift shoulders towards ears, hunch

forward, sit with weight on one hip

Neutral Seated Position

Neutral Seated Position

Neutral Seated Position

Forearm and Wrist straight

Neutral Seated Position

FEET◦Flat on Floor◦Create a wide base of support◦Shoulder’s width apart

Neutral Seated Position

Incorrect Feet

Feet right next Feet on top of to one another one another

WORKING DISTANCE

Wilkins p.91

WHICH ONE IS CORRECT?

STOOLPosition buttocks all way back in chairDistribute weight evenly on both hips

Nield p.15

Nield p.15

Adjust LUMBAR DEPTH by moving the backrest closer or farther from the seat pan until the backrest nestles against the lower back

The unsupported lower back tends to straighten rather than maintain a healthy curve

Nield p.16

Adjust LUMBAR HEIGHT by moving backrest up or down until it nestles in the neutral lumbar curve of the lower backHelps support the natural curve of the spine

Nield p.16

Raise tailbone up to establish correct spinal curves

All 3 normal back curves should be present while sitting

Studies show position of the pelvis determines the shape of the spine

Nield p.16

Pull stomach muscles toward the spineSuck in tummy!!Adds stability and decreases strain on back

Nield p.16

Review

Which of the following is not correct positioning for a clinician in neutral position?

A) Shoulders are relaxed and perpendicular with

the hips and floorB) Elbows are held close to the bodyC) Forearms are maintained parallel with the

floorD) Feet are flat on the floor, knees slightly

apart, and weight evenly distributed

Answer

A) Shoulders are relaxed and perpendicular with the hips and floor is the correct answer.

Shoulders are relaxed and parallel with the hips and floor. Elbows are close to the body. Forearms are parallel with the floor. Forearms and wrists are in a straight line. The full body weight is distributed evenly on the seat; there is comfortable space (about 3 inches) between the edge of the seat and the back of the knee. Knees are slightly apart, and feet are flat on the floor.

OBJECTIVE #3Patient Positioning

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Patient ChairClient-Clinician Positioning FactorsCommonly used client positions are:

1. Upright for interviewing and educating

2. Semisupine/Semi-upright (patients with cardiovascular or respiratory diseases)

3. Supine ideal for patient tx4. Trendelenburg for medical emerg

(syncope). Brain lower then heart

Wilkins p.90

UPRIGHT

SEMI-SUPINE

SUPINE

TRENDELENBURG

Wilkins p.90

Patient Chair

Contraindications for supine position◦Congestive heart disease◦Vertigo◦Emphysema◦Severe asthma◦Sinusitis◦During the third trimester of pregnancy, some

women may be uncomfortable

Patient Chair: Maxillary Arch Tx

Nield p.19

Body◦Pt’s feet should be even with or slightly higher than

the tip of noseChair Back

◦Parallel to the floorHead

◦Top of pt head even with the upper ridge of the headrest

Headrest◦Pt’s head is in chin-up position: nose and chin level

Patient Chair: Maxillary Arch TxNield p.19

Patient Chair: Mandibular Arch Tx

Nield p.20

Body◦Pt’s feet should be even with or slightly higher than the

tip of noseChair Back

◦Slightly raised above the parallel position at 15-20° to the floor

Head◦Top of pt head even with the upper edge of the headrest

Headrest◦Pt’s head is in chin-down position: chin lower than the

nose

Patient Chair: Mandibular Arch Tx

Nield p.20

How to Find Correct Height of Patient Chair for YOU!

1. Assume neutral seated position2. Sit next to patient with forearms crossed at

your waist3. Position chair for maxillary or mandibular

work4. Position pt’s head for treatment (chin-up or

down)5. When pt opens mouth, should be below the

point of your elbow

Nield p.25-26

ReviewWhy should the patient remain seated in the upright

position for a couple of minutes after being reclined?A) To allow the patient to receive postoperative instructionsB) To allow all the patients saliva to flow back into the mouth and be expectorated before the patient leaves the operatoryC) To avoid possible postural hypotensionD) There is no reason for the patient to remain seated after treatment

Answer

C) To avoid possible postural hypotension is the correct answer.

As the blood flows away from the brain upon being placed in an upright position after being reclined for a period of time, the blood pressure may drop and the patient may experience syncope, or fainting.

OBJECTIVE #4Light & Instrument Tray

Vision: Lighting

Can focus beam of lightLight should be in arm’s reach

Lighting Maxillary Arch

Ranges from directly over the oral cavity to a position over the patient’s neck

Light beam is perpendicular to floor◦ 60-45° angle to floor

Patient Chin-Up position

Nield p.23

Lighting Mandibular Arch

Positioned directly over the oral cavityPatient in chin-down positionLight beam directly perpendicular to the floor

Nield p.23

Wilkins p.93

Loupes and LightingLoupes magnify field of visionMany loupe’s now sold with light

illuminators

Nield p.28-33

Instrument Tray

Within reach of your dominant handToo high = stress on body

Instrument Tray

Can be next to patient (our clinic)Can be on top of patient

Handpieces and Cords

Handpieces◦Ergonomic design features are smaller, lighter

better fitted to RDH handsCords

◦Improper management can cause drag on hands, wrist, arm

◦Straight better then curly

What’s Wrong with this Picture?DH Student

OBJECTIVE #5Clock Positions

Clock Positions for Instrumentation

Clinician moves around patient while performing instrumentation

Goal: correct positioning of patient and clinician facilitates neutral positioning and optimal visual field = decreases fatigue and strain

Clock positions help us know where to sit while we work on different areas of the mouth

Patients move heads to help us see (turn toward/away from me)

Nield Book – CH2

Copyright © 2010 by Saunders, an imprint of Elsevier Inc.

63

Clock PositionsRIGHT-HANDED CLINICIAN

1. 8 O’clock2. 9 O’clock3. 10-11 O’clock4. 12 O’clock

Clock PositionsLEFT-HANDED CLINICIAN

1. 3 O’clock2. 4 O’clock3. 1-2 O’clock4. 12 O’clock

Clock PositionsRIGHT-HANDED CLINICIAN

8 O’clock◦Torso: face patient with hips in line

with patient’s upper arm◦Leg: thighs rest against side of patient

chair◦Arm: slightly away from your sides◦Line of Vision: straight ahead into pt

mouth

Clock PositionsRIGHT-HANDED CLINICIAN

9 O’clock◦Torso: face side of pt’s head.

Midline of torso even w/ pt mouth◦Leg

1. Straddle patient chair (BEST)2. Underneath headrest

◦Arm: Lower half of RT arm in alignment w/pt shoulder. LF hand/wrist over region of pt RT eye

◦Line of Vision: straight down into pt mouth

Clock PositionsRIGHT-HANDED CLINICIAN

10-11 O’clock◦Torso: Sit top RT corner of

headrest, midline torso even w/temple region of pt head

◦Leg: straddle corner of headrest◦Arm: RT hand directly across

corner of pt mouth. LF hand & wrist above pt nose & forehead

◦Line of Vision: straight down into pt mouth

Clock PositionsRIGHT-HANDED CLINICIAN

12 O’clock◦Torso: Sit behind pt head◦Leg: straddle headrest◦Arm: Wrist & hand above

region of pt ears/cheeks◦Line of Vision: straight down

into pt’s mouth

Clock PositionsLEFT-HANDED CLINICIAN

1. 4 O’clock2. 3 O’clock3. 1-2 O’clock4. 12 O’clock

Clock PositionsLEFT-HANDED CLINICIAN

4 O’clock◦Torso: Hips in line w/pt upper

arm◦Leg: Thighs rest against side

of pt chair◦Arm: Arms slightly away from

sides. Lower LF arm over pt chest. Side of RT hand rests in area of pt RT cheekbone

◦Line of Vision: straight ahead into pt mouth

Clock PositionsLEFT-HANDED CLINICIAN

3 O’clock◦ Torso: Face pt head, midline torso

even w/pt mouth◦ Leg

1. Straddle patient chair (BEST)2. Underneath headrest

◦ Arm: Lower half of LF arm in alignment w/pt shoulder. RT hand/wrist over region of pt LF eye

◦ Hand: RT hand in area of pt LF cheekbone. Fingertips LF hand on pm teeth of mandibular LF posterior sextant

◦ Line of Vision: straight down into pt’s mouth

Clock PositionsLEFT-HANDED CLINICIAN

1 O’clock◦Torso: Sit top corner of headrest,

midline torso even w/ temple of pt head

◦Leg: straddle corner of headrest◦Arm: LF hand directly across corner

of pt mouth, RT hand & wrist above pt nose & forehead

◦Line of Vision: straight down into pt mouth

Clock PositionsLEFT-HANDED CLINICIAN

12 O’clock◦Torso: Sit behind pt head◦Leg: straddle headrest◦Arm: Wrist & hand above region

of pt ears/cheeks◦Line of Vision: straight down

into pt mouth

OBJECTIVE #6How To Prevent Injury

Nield p.81-83

79

Physical ExerciseStrengthening ExercisesPerforme regularly to repair, build &

maintain healthy musculoskeletal system

Dexterity Development

Strength-Training for back, shoulders, hands, wrists, fingers, arms

Squeezing therapy putty/soft ball◦Purpose: develop strength & control

Stretching

Purposes◦Before & After Work

Rubber band on finger joints

WILKINS & NEILD VIDEO