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Ergonomic Applications to Ergonomic Applications to Dental PracticeDental Practice
Ir. Sudiyono Kromodihardjo MSc. PhD
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OverviewOverview
What is Ergonomics? What are the Consequences of Poor
Ergonomics? What Policies/Standards Address
Ergonomics? How can Ergonomic Principles Be
Applied to Dental Practice?
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JobCharacteristics
HumanCapabilities
What is Ergonomics?What is Ergonomics?
ERGONOMICS is a way to work smarter--not harder by designing tools, equipment, work stations and tasks to fit the job to the worker--NOT the worker to the job
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Ergonomics
• Relationship between humans, the tasks they perform, and the environment in which tasks are performed.
• Equipment-centered Ergonomics: Human Adaptation to Requirements of Equipment.
• Human-centered Ergonomics: Equipment is adapted to Requirements of Humans.
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Humans Do DentistryNot Equipment
Priority: Human Factors and the Way We Work
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Ergonomic Design GoalsErgonomic Design Goals Improve job process by eliminating unnecessary
tasks, steps & effort Reduce potential for overexertion injury Minimize mental / physical fatigue potential Leverage workers’ skills / knowledge of their
jobs to re-design work to increase their satisfaction, comfort, morale and fulfillment
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Consequences of Poor DesignConsequences of Poor Design Discomfort Chronic Pain Accidents Injuries
Fatigue Increased Errors Work-Related Musculoskeletal
Disorders (WMSDs) Low back pain Tendonitis Epicondylitis Bursitis Carpal tunnel syndrome
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U.S. Navy Ergo-Injuries
Source: OSHSYS RAW DATA FY 89 to FY 97
Non Ergonomic Related Cases Declined
Compensation Cases FY89 - FY97
-
4,000
8,000
12,000
16,000
20,000
24,000
FY89 FY90 FY91 FY92 FY93 FY94 FY95 FY96 FY97
Num
ber
of C
ases
Ergonomic Related Cases Non Ergonomic Related Cases
Ergonomic - Carpal Tunnel Syndrome, Chrondromalacia, Back Strain, Multiple Strain
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WMSDs in DentistryWMSDs in Dentistry
?
?
??
?
?
??
??
? ?
? ?
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75%Studies have shown
of dentists & hygienists suffer from musculoskeletal disordersthat affect occupational health
& the quality of practice life
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WMSDs in DentistryWMSDs in DentistryReasons for Early Retirement Among DentistsReasons for Early Retirement Among Dentists
Musculoskeletal Disorders (29.5%) Cardiovascular Disease (21.2%) Neurotic Symptoms (16.5%) Tumors (7.6%) Diseases of the Nervous System (6.1%)
Source: Burke et al., 1997
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WMSD Symptoms Among WMSD Symptoms Among DentistsDentists
0%10%20%30%40%50%60%70%80%
Body Part
% R
ep
ort
ing
Males
Females
Source: Finsen et al., 1998
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WMSD Symptoms Among WMSD Symptoms Among Dental HygienistsDental Hygienists
01020304050607080
*DiagnosedCTS
*Hand-wristpain
*Shoulderpain
*Neck pain Low Backpain
% R
epor
ting
Dental Hygienists Dental Assistants
Source: Liss et al., 1995* indicates difference is significant
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ImagineDental practice
without the compromise of your health, the quality of care you provide,
& the quality of practice life you deserve.
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ImagineDental practice
free from back, neck & shoulder pain that afflict so many clinicians every workday.
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ImagineReaching your peak performance potential
while you work comfortably,with energy & enthusiasm left over
at the end of the day.
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What Factors Contribute to WMSDs?What Factors Contribute to WMSDs?
Repetitive motions (e.g., scaling, polishing)
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What Factors Contribute to WMSDs?What Factors Contribute to WMSDs?
Static neck, back, and shoulder postures
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What Factors Contribute to WMSDs?What Factors Contribute to WMSDs?
Grasping small instruments for prolonged periods
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What Factors Contribute to WMSDs?What Factors Contribute to WMSDs?
Prolonged use of vibrating hand tools
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Applying Ergonomics Principles Applying Ergonomics Principles to Dental Workto Dental Work
Tools/InstrumentsTools/Instruments
WorkstationsWorkstations
Work PracticesWork Practices
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Ergonomics in DentistryErgonomics in DentistryTool/Instrument DesignTool/Instrument Design
Considerations: Overall shape/size Handle shape/size Weight Balance Maneuverability Ease of operation Ease of maintenance
Goals: Reduce force exertion;Maintain hand/wrist in neutral posture
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Ergonomics in DentistryErgonomics in DentistryHand InstrumentsHand Instruments
Look for: Hollow or resin
handles Round, knurled or
compressible handles Carbon steel
construction (for instruments with sharp edges)
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Ergonomics in DentistryErgonomics in DentistryAutomatic HandpiecesAutomatic Handpieces
Look for: Lightweight, balanced models (cordless preferred) Sufficient power Built-in light sources Angled vs. straight-shank Pliable, lightweight hoses Swivel mechanisms Easy activation Easy maintenance
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Ergonomics in DentistryErgonomics in DentistrySyringes and DispensersSyringes and Dispensers
Look for: Adequate lumen
size Ease in cleaning Knurled handles
(no finger cut-outs) Easy activation and
placement
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Ergonomics in DentistryErgonomics in DentistryMagnification SystemsMagnification Systems
Consider: Working distance Depth of field Declination angle Convergence angle Magnification factor Lighting needs
Goal: Improve neck posture; Provide clearer vision
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Ergonomics in DentistryErgonomics in DentistryWorkstation LayoutWorkstation Layout
Ensure: Instruments, materials, medications, etc. are accessible while seated Hoses are positioned away from the body Set-up can be adapted for different operators
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Ergonomics in Dentistry Ergonomics in Dentistry Operator ChairOperator Chair
Look for: Stability (5 legged base w/casters) Lumbar support Hands-free seat height adjustment Adjustable foot rests Adjustable, wrap-around body support Seamless upholstery
Goal: Promote mobility and patient access;accommodate different body sizes
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Ergonomics in Dentistry Ergonomics in Dentistry Patient ChairPatient Chair
Look for: Stability Pivoting or drop-down arm rests (for patient ingress/egress) Supplemental wrist/forearm support (for operator) Articulating head rests Hands-free operation
Goal: Promote patient comfort; maximize patient access
INSTITUTE FOR ENVIRONMENT, SAFETY AND OCCUPATIONAL HEALTH RISK ANALYSISErgonomics in Dentistry Ergonomics in Dentistry Posture/PositioningPosture/Positioning
Goal: Avoid static and/or awkward postures
Potential Strategies: Position patient so that operator’s elbows are
elevated no more than 30 degrees.
Adjust patient chair when accessing different quadrants
Alternate between standing and sitting
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Ergonomics in Dentistry Ergonomics in Dentistry Work PracticesWork Practices
Goal: Maintain neutral posture, reduce force requirements
Potential Strategies: Ensure tools are sharpened, well-maintained Use automatic handpieces instead of manual
instruments where possible Use full-arm strokes rather than wrist strokes
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Ergonomics in Dentistry Ergonomics in Dentistry SchedulingScheduling
Potential Strategies: Increase treatment time for more difficult
patients Alternate heavy and light calculus patients
within a flexible scheduling system Vary procedures within the same appointment Shorten patient’s recall interval
Goal: Provide sufficient recovery time for staff to avoid chronic muscular fatigue
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Ergonomics in Dentistry Ergonomics in Dentistry Prosthetics LabsProsthetics Labs
Naval Station Rota Spain Clinic Case Study: Lab techs mentioned chronic back, shoulder & neck discomfort / pain during periodic Industrial Hygiene survey from working at non-adjustable bench in obviously stressful static postures -- with no forearm support nor bench edge padding
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Ergonomics in Dentistry Ergonomics in Dentistry Prosthetics LabsProsthetics Labs
Naval Station Rota Spain Clinic Case Study -- Post intervention improvements offered by Kavo ergonomic lab benches : Lab techs affirm GREATLY increased comfort / decrease in back, shoulder & neck discomfort / pain.
KAVO dental prosthesis lab benches offer ample forearm supports and workpiece support centering prosthesis directly below technician which optimizes spinal / neck / head vertical alignment
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Ergonomics in Dentistry Ergonomics in Dentistry Prosthetics LabsProsthetics Labs
Naval Station Rota Spain Clinic Case Study: Lab technicians now work in optimized ergonomic posture. In addition to forearm supports and central workpiece support (locally-ventilated for air contaminant removal !) , the table also has much improved overhead lighting, a magnifying lens and a drill speed control operated by the tech’s right knee
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ERGONOMICS SUMMARY
• Good ergonomic design of tools, processes and furniture DOES improve personnel comfort, health, morale, productivity and readiness.
• Individual effort as part of a workshop team is the greatest means of identifying / improving workplace ergonomic issues.
• It’s critical to seek prompt medical aid for symptoms of ergonomic stress / CTDs
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• Self-derivation of a natural and comfortable posture for comprehensive patient care
• Positioning of patients to maintain posture and optimize visual and physical control of intra-oral procedures
• Operatory light positioning to provide adequate illumination from one location with minimal adjustment
• Correctly positioning the dental assistant for efficiency and effectiveness in support of patient care
• Positioning all equipment and instrument items in the operatory proximal to the practitioner and the assistant to reduce unnecessary exertion and fatigue
Learn to Prevent or Reduce Occupational Ailments
By the following…
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• Using instrument grips that ensure stabilization and control of performance
• Maximizing the potential of the mirror when direct vision compromises posture
• Selection of magnifying loupes that do not induce musculoskeletal pain
• Selection of equipment designed to optimize a comfortable working environment
• Using 5 movements for control of optimal posture in a 10-step decision process that assures performance without compromise of self, patient, or task
Learn to Prevent or Reduce Occupational Ailments continued