DH101 Preclinical Sciences Ergonomics Nield Book CH 1&2 Wilkins CH7 Lisa Mayo, RDH, BSDH Staci Janous, RDH, BS Concorde Career College

Topics To Cover Today 1. Principles of Ergonomics 2. Positioning of Clinician (neutral position, stool) 3. Patient Positioning 4. Light & Instrument Tray 5. Clock Positions 6. How To Prevent Injury

OBJECTIVE #1 Principles of Ergonomics

Copyright © 2010 by Saunders, an imprint of Elsevier Inc.4 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 positions 2)Excessive use of small muscles 3)Tight grips 4)Repetitive movements 5)Positioning challenges 6)Confined working spaces Nield p.5

Copyright © 2010 by Saunders, an imprint of Elsevier Inc.5 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 #2 Positioning 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 Position NECK ◦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

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 nextFeet on top of to one anotherone another

WORKING DISTANCE Wilkins p.91

WHICH ONE IS CORRECT?

STOOL Position buttocks all way back in chair Distribute weight evenly on both hips 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 back Helps 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 spine Suck 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 floor B) Elbows are held close to the body C) Forearms are maintained parallel with the floor D) 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 #3 Patient Positioning

32 Patient Chair Client-Clinician Positioning Factors Commonly 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 tx 4. 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 nose Chair Back ◦Parallel to the floor Head ◦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 Tx Nield 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 nose Chair 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 position 2. Sit next to patient with forearms crossed at your waist 3. Position chair for maxillary or mandibular work 4. 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

Review Why 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 instructions B) To allow all the patients saliva to flow back into the mouth and be expectorated before the patient leaves the operatory C) To avoid possible postural hypotension D) 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 #4 Light & Instrument Tray

Vision: Lighting Can focus beam of light Light 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 cavity Patient in chin-down position Light beam directly perpendicular to the floor Nield p.23

Wilkins p.93

Loupes and Lighting Loupes magnify field of vision Many loupe’s now sold with light illuminators Nield p.28-33

Instrument Tray Within reach of your dominant hand Too 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 hands Cords ◦Improper management can cause drag on hands, wrist, arm ◦Straight better then curly

What’s Wrong with this Picture? DH Student

OBJECTIVE #5 Clock 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 Positions RIGHT-HANDED CLINICIAN 1. 8 O’clock 2. 9 O’clock O’clock O’clock

Clock Positions LEFT-HANDED CLINICIAN 1. 3 O’clock 2. 4 O’clock O’clock O’clock

Clock Positions RIGHT-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 Positions RIGHT-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 Positions RIGHT-HANDED CLINICIAN 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 Positions RIGHT-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 Positions LEFT-HANDED CLINICIAN 1. 4 O’clock 2. 3 O’clock O’clock O’clock

Clock Positions LEFT-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 Positions LEFT-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 Positions LEFT-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 Positions LEFT-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 #6 How To Prevent Injury Nield p.81-83

79 Physical Exercise Strengthening Exercises Performe 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