musculoskeletal disorders and ergonomics in dentistry: an introduction

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Musculoskeletal Disorders and Ergonomics in Dentistry: An Introduction

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Musculoskeletal Disorders and

Ergonomics in Dentistry: An Introduction

Musculoskeletal Musculoskeletal Disorders (MSDs)Disorders (MSDs)

Include a group of conditions Include a group of conditions that involve nerves, tendons, that involve nerves, tendons, muscles, and supporting muscles, and supporting structures such as intervertebral structures such as intervertebral discsdiscs

Severity of Symptoms

Mild periodic Severe chronic & debilitating conditions

MSDs MSDs == ErgonomicsErgonomics

Musculoskeletal problems Musculoskeletal problems are the problem and are the problem and ergonomics is a solution.ergonomics is a solution.

Types of MSDsTypes of MSDs Neck and Shoulder Neck and Shoulder

DisordersDisorders Myofascial Pain DisorderMyofascial Pain Disorder Cervical SpondylolysisCervical Spondylolysis Thoracic Outlet Thoracic Outlet

SyndromeSyndrome Rotator Cuff Rotator Cuff

Tendinitis/TearsTendinitis/Tears

Back DisordersBack Disorders Herniated Spinal DiscHerniated Spinal Disc Lower Back Pain Lower Back Pain SciaticaSciatica

Hand and Wrist Hand and Wrist DisordersDisorders DeQuervain’s DiseaseDeQuervain’s Disease Trigger FingerTrigger Finger Carpal Tunnel Carpal Tunnel

SyndromeSyndrome Guyon’s SyndromeGuyon’s Syndrome Cubital Tunnel Cubital Tunnel

SyndromeSyndrome Hand-Arm Vibration Hand-Arm Vibration

SyndromeSyndrome Raynaud’s Raynaud’s

PhenomenonPhenomenon

MSDsMSDs

Signs Signs SymptomsSymptoms

Decreased Decreased range of range of motionmotion

DeformityDeformity Decreased grip Decreased grip

strengthstrength Loss of muscle Loss of muscle

functionfunction

PainPain NumbnessNumbness TinglingTingling BurningBurning CrampingCramping StiffnessStiffness

Contributing Factors for Contributing Factors for Work-Related MSDsWork-Related MSDs

(WMSD) (WMSD) Routine exposure to:Routine exposure to:

Forceful hand exertionsForceful hand exertions Repetitive movementsRepetitive movements Fixed or awkward posturesFixed or awkward postures Vibrating toolsVibrating tools Unassisted frequent or heavy Unassisted frequent or heavy

liftinglifting

What Factors Contribute What Factors Contribute to WMSDs?to WMSDs?

Forceful hand exertionsForceful hand exertions Grasping small instruments for Grasping small instruments for

prolonged periodsprolonged periods Forceful squeezing/release of Forceful squeezing/release of

instrumentsinstruments Repetitive movements—e.g., Repetitive movements—e.g.,

scaling, root planing, polishingscaling, root planing, polishing

What Factors Contribute What Factors Contribute to WMSDs?to WMSDs?

Fixed or awkward posturesFixed or awkward postures Neck, back, shoulder postureNeck, back, shoulder posture Hand/wrist positionsHand/wrist positions Standing/sittingStanding/sitting Operatory organizationOperatory organization Patient positioningPatient positioning

What Factors Contribute What Factors Contribute to WMSDs?to WMSDs?

Prolonged use of vibrating hand Prolonged use of vibrating hand tools—dental handpieces, tools—dental handpieces, laboratory equipmentlaboratory equipment

Contributing Factors for Contributing Factors for WMSDsWMSDs

A risk factor is not always a A risk factor is not always a causation factorcausation factor

The level of risk depends on The level of risk depends on Length of time a worker is Length of time a worker is

exposed to these conditionsexposed to these conditions How often they are exposedHow often they are exposed Level of exposureLevel of exposure

Usually a combination of multiple Usually a combination of multiple risk factors (vs. a single factor) risk factors (vs. a single factor) contributes to or causes a MSDcontributes to or causes a MSD

Contributing Factors for Contributing Factors for WMSDsWMSDs

Do not focus solely on the Do not focus solely on the workplaceworkplace Risk factors may be experienced Risk factors may be experienced

during non-occupational during non-occupational activities (e.g., certain sports, activities (e.g., certain sports, exercising, working with exercising, working with computers, needlework, playing computers, needlework, playing musical instruments)musical instruments)

Contributing Factors for Contributing Factors for WMSDsWMSDs

Not everyone exposed to any or Not everyone exposed to any or all of the risk factors will develop all of the risk factors will develop a MSDa MSD

Individuals do not respond to Individuals do not respond to them in the same waythem in the same way

Predisposing factors such as age, Predisposing factors such as age, arthritis, renal disease, hormonal arthritis, renal disease, hormonal imbalances, diabetes, and imbalances, diabetes, and hypothyroidism may play a rolehypothyroidism may play a role

Neck and Shoulder Neck and Shoulder DisordersDisorders

Risk factors associated with Risk factors associated with dentistrydentistry Prolonged static neck flexion and Prolonged static neck flexion and

shoulder abduction or flexionshoulder abduction or flexion Lack of upper-extremity supportLack of upper-extremity support Inadequate work breaksInadequate work breaks

Neck and Shoulder Neck and Shoulder DisordersDisorders

Dental health-care personnel (DHCP) Dental health-care personnel (DHCP) commonly assume awkward work commonly assume awkward work posturespostures To obtain better views of the intraoral To obtain better views of the intraoral

cavitycavity To provide a more comfortable To provide a more comfortable

position for the patientposition for the patient To coordinate their position relative to To coordinate their position relative to

the dentist or assistantthe dentist or assistant While operating equipment and While operating equipment and

reaching for instruments and suppliesreaching for instruments and supplies

Neck and Shoulder Neck and Shoulder DisordersDisorders

ExamplesExamples Myofascial Pain Disorder Myofascial Pain Disorder Cervical SpondylolysisCervical Spondylolysis Thoracic Outlet SyndromeThoracic Outlet Syndrome Rotator Cuff Tendinitis/TearsRotator Cuff Tendinitis/Tears

Neck and Shoulder Neck and Shoulder DisordersDisorders

Myofascial Pain DisorderMyofascial Pain Disorder

Pain and tenderness in the neck, Pain and tenderness in the neck, shoulder, arm musclesshoulder, arm muscles

Painful trigger points—may Painful trigger points—may twitch upon touch or massagetwitch upon touch or massage

Restricted range of motionRestricted range of motion Possible causes: overloaded Possible causes: overloaded

neck/shoulder musclesneck/shoulder muscles

Neck and Shoulder Neck and Shoulder DisordersDisorders

Cervical SpondylosisCervical Spondylosis

Intermittent/chronic neck and Intermittent/chronic neck and shoulder pain or stiffnessshoulder pain or stiffness

HeadacheHeadache Hand and arm pain, numbness, Hand and arm pain, numbness,

tingling, clumsiness may occurtingling, clumsiness may occur Possible causes: age-related spinal Possible causes: age-related spinal

disc degeneration leading to nerve disc degeneration leading to nerve compression and spinal cord damage; compression and spinal cord damage; arthritisarthritis

Neck and Shoulder Neck and Shoulder DisordersDisorders

Thoracic Outlet SyndromeThoracic Outlet Syndrome

Pain in the shoulder, arm or hand (can Pain in the shoulder, arm or hand (can be all three)be all three)

Numbness, tingling of fingersNumbness, tingling of fingers Muscle weakness/fatigueMuscle weakness/fatigue Cold arm or handCold arm or hand Possible causes: compressed nerves or Possible causes: compressed nerves or

blood vessels passing into arms; blood vessels passing into arms; trauma; slouching forward or dropping trauma; slouching forward or dropping shouldersshoulders

Neck and Shoulder Neck and Shoulder DisordersDisorders

Rotator Cuff Rotator Cuff Tendinitis/Tears Tendinitis/Tears

Pain and stiffness in the shoulder Pain and stiffness in the shoulder associated with backward and associated with backward and upward arm movementsupward arm movements

Weakness of rotator cuff musclesWeakness of rotator cuff muscles Possible causes: swelling or tearing Possible causes: swelling or tearing

of rotator cuff soft tissue; shoulder of rotator cuff soft tissue; shoulder joint bone spurs/abnormalities; joint bone spurs/abnormalities; poor shoulder posturepoor shoulder posture

Hand and Wrist DisordersHand and Wrist Disorders Risk factors associated with dentistryRisk factors associated with dentistry

Chronic repetitive movements of the hand Chronic repetitive movements of the hand and wrist and wrist

Abnormal or awkward positions of the Abnormal or awkward positions of the wristwrist

Mechanical stresses to digital nerves such Mechanical stresses to digital nerves such as sustained grasps on instrument handlesas sustained grasps on instrument handles

Forceful workForceful work Extended use of vibratory instrumentsExtended use of vibratory instruments Inadequate work breaksInadequate work breaks

Hand and Wrist DisordersHand and Wrist Disorders

Examples Examples DeQuervain’s DiseaseDeQuervain’s Disease Trigger FingerTrigger Finger Carpal Tunnel SyndromeCarpal Tunnel Syndrome Guyon’s SyndromeGuyon’s Syndrome Cubital Tunnel SyndromeCubital Tunnel Syndrome Hand-Arm Vibration SyndromeHand-Arm Vibration Syndrome Raynaud’s PhenomenonRaynaud’s Phenomenon

Hand and Wrist DisordersHand and Wrist DisordersDeQuervain’s DiseaseDeQuervain’s Disease

Pain in thumb and wrist area when Pain in thumb and wrist area when grasping, pinching, twistinggrasping, pinching, twisting

Swelling in thumb areaSwelling in thumb area Decreased range of motion of Decreased range of motion of

thumb with painthumb with pain Possible causes: synovial sheath Possible causes: synovial sheath

swelling; thickening of tendons at swelling; thickening of tendons at base of thumb; repeated trauma or base of thumb; repeated trauma or twisting hand/wrist motionstwisting hand/wrist motions

Hand and Wrist DisordersHand and Wrist Disorders Trigger Finger (Tenosynovitis)Trigger Finger (Tenosynovitis)

Pain during movement that place Pain during movement that place tendons in tensiontendons in tension

Warmth, swelling, tenderness of Warmth, swelling, tenderness of the tendon when palpatedthe tendon when palpated

Possible causes: sustained, Possible causes: sustained, forceful powerful grip and/or forceful powerful grip and/or repetitive motionrepetitive motion

Hand and Wrist Hand and Wrist Disorders Disorders Carpal Tunnel Carpal Tunnel

SyndromeSyndrome Hand or finger numbness, pain, tingling, Hand or finger numbness, pain, tingling,

burning, clumsinessburning, clumsiness Eventual muscle weakness and atrophyEventual muscle weakness and atrophy Symptoms often worse with increased activitySymptoms often worse with increased activity Pain or tingling that awakens the patient at Pain or tingling that awakens the patient at

night with relief via shaking/massaging the night with relief via shaking/massaging the hand is considered a hallmark symptom for hand is considered a hallmark symptom for diagnosisdiagnosis

Possible causes: compressed median nerve in Possible causes: compressed median nerve in wrist via trauma, forceful exertion, repetitive wrist via trauma, forceful exertion, repetitive and awkward movements that deviate from and awkward movements that deviate from near-neutral positionsnear-neutral positions

Hand and Wrist DisordersHand and Wrist DisordersCarpal Tunnel SyndromeCarpal Tunnel Syndrome

All hand pain does not mean All hand pain does not mean carpal tunnel syndromecarpal tunnel syndrome

DHCP do not appear to be at DHCP do not appear to be at greater risk compared to the greater risk compared to the general population for general population for developing carpal tunnel developing carpal tunnel syndromesyndrome

Hamann C, Werner RA, Franzblau A, Rodgers PA, Siew C, Gruninger S. Hamann C, Werner RA, Franzblau A, Rodgers PA, Siew C, Gruninger S. Prevalence of carpal tunnel syndrome and median mononeuropathy Prevalence of carpal tunnel syndrome and median mononeuropathy among dentists. J Am Dent Assoc. 2001;132:163-170.among dentists. J Am Dent Assoc. 2001;132:163-170.

Werner RA, Hamann C, Franzblau A, Rodgers PA. Prevalence of carpal Werner RA, Hamann C, Franzblau A, Rodgers PA. Prevalence of carpal tunnel syndrome and upper extremity tendinitis among dental tunnel syndrome and upper extremity tendinitis among dental hygienists. J Dent Hyg. 2002;76:126-132. hygienists. J Dent Hyg. 2002;76:126-132.

Hand and Wrist DisordersHand and Wrist DisordersGuyon’s SyndromeGuyon’s Syndrome

Pain, weakness, numbness, tingling, Pain, weakness, numbness, tingling, burning in the little finger and part of burning in the little finger and part of the ring fingerthe ring finger

Symptoms may worsen at night or early Symptoms may worsen at night or early morningmorning

Possible causes: compressed ulnar Possible causes: compressed ulnar nerve in Guyon’s canal at the base of nerve in Guyon’s canal at the base of the palm; repetitive wrist flexing; the palm; repetitive wrist flexing; excessive pressure on palm/base of excessive pressure on palm/base of handhand

Hand and Wrist DisordersHand and Wrist Disorders Cubital Tunnel SyndromeCubital Tunnel Syndrome

Pain, numbness, tingling and impaired Pain, numbness, tingling and impaired sense of touch in the little and ring sense of touch in the little and ring fingers, side and back of handfingers, side and back of hand

Loss of fine controlLoss of fine control Reduced grip strengthReduced grip strength Possible causes: compressed ulnar Possible causes: compressed ulnar

nerve in elbow due to trauma or nerve in elbow due to trauma or repeated use; prolonged use of elbow repeated use; prolonged use of elbow while flexedwhile flexed

Hand and Wrist DisordersHand and Wrist DisordersHand-Arm Vibration SyndromeHand-Arm Vibration Syndrome

Intermittent or chronic finger and Intermittent or chronic finger and hand numbness and blanchinghand numbness and blanching

Reduced dexterity, grip strength, and Reduced dexterity, grip strength, and sensationsensation

Greater sensitivity to coldGreater sensitivity to cold Possible causes: vibrations may injure Possible causes: vibrations may injure

nerves leading to decreased blood nerves leading to decreased blood flow and lower oxygen supply to flow and lower oxygen supply to surrounding tissuessurrounding tissues

Hand and Wrist DisordersHand and Wrist Disorders Raynaud’s PhenomenonRaynaud’s Phenomenon

Intermittent spasm of finger and toe Intermittent spasm of finger and toe blood vessels causing blanching, blood vessels causing blanching, numbness, and painnumbness, and pain

Increased sensitivity to cold Increased sensitivity to cold temperaturestemperatures

Possible causes: carpal tunnel syndrome, Possible causes: carpal tunnel syndrome, connective tissue diseases, repeated connective tissue diseases, repeated vibration or use of tools that vibratevibration or use of tools that vibrate

Back DisordersBack Disorders

Risk factors associated with Risk factors associated with dentistrydentistry Awkward postureAwkward posture

Examples Examples Herniated Spinal DiscHerniated Spinal Disc Lower Back Pain Lower Back Pain SciaticaSciatica

Back DisordersBack Disorders Herniated Spinal DiscHerniated Spinal Disc

Back and leg numbness, tingling, Back and leg numbness, tingling, pain, weaknesspain, weakness

Worsens with coughing, sneezing, Worsens with coughing, sneezing, sitting, driving, bending forwardsitting, driving, bending forward

Possible causes: bulging or Possible causes: bulging or fragmenting of intervertebral discs fragmenting of intervertebral discs into spinal canal compressing and into spinal canal compressing and irritating spinal nerves; excessive irritating spinal nerves; excessive heavy lifting without adequate restheavy lifting without adequate rest

Back DisordersBack Disorders Lower Back PainLower Back Pain

PainPain Stiffness in lower spine and Stiffness in lower spine and

surrounding tissues surrounding tissues Possible causes: heavy lifting Possible causes: heavy lifting

and forceful movements; whole and forceful movements; whole body vibration; bending/twisting; body vibration; bending/twisting; awkward static posturesawkward static postures

Back DisordersBack DisordersSciaticaSciatica

Pain from lower back or hip Pain from lower back or hip radiating to the buttocks and legsradiating to the buttocks and legs

Leg weakness, numbness, or Leg weakness, numbness, or tinglingtingling

Possible causes: prolapsed Possible causes: prolapsed intervertebral disc pressuring the intervertebral disc pressuring the sciatic nerve; worsened with sciatic nerve; worsened with prolonged sitting or excessive prolonged sitting or excessive bending/liftingbending/lifting

Treatment and Treatment and Management of MSDsManagement of MSDs

Obtain an accurate diagnosis Obtain an accurate diagnosis from a qualified health-care from a qualified health-care providerprovider Early intervention is keyEarly intervention is key

Self-diagnosis is not Self-diagnosis is not recommendedrecommended MSD origins are complex with a MSD origins are complex with a

broad range of symptomsbroad range of symptoms

Treatment and Treatment and Management of MSDsManagement of MSDs

Diagnostic tests may include Diagnostic tests may include physical exams, provocative physical exams, provocative tests, and electromyographytests, and electromyography

Treatment may range from pain-Treatment may range from pain-relief medications and rest to relief medications and rest to surgery, and ergonomic surgery, and ergonomic interventions both at work and interventions both at work and homehome

What is Ergonomics?What is Ergonomics?

“ “Ergo” means workErgo” means work “ “Nomos” means natural laws or systemsNomos” means natural laws or systems

Ergonomics is the science of workErgonomics is the science of work Ergonomics is much broader than Ergonomics is much broader than

preventing work-related musculoskeletal preventing work-related musculoskeletal disordersdisorders

Ergonomics plays an important role in Ergonomics plays an important role in preventing injury and illnesspreventing injury and illness

What is Ergonomics?What is Ergonomics?

An applied An applied science science concerned with concerned with designing and designing and arranging things arranging things people use so people use so that the people that the people and things and things interact most interact most efficiently and efficiently and safelysafely

Job Demands

Worker Capabilities

"fitting the job task to the person performing the job"

Consequences of Poor Consequences of Poor DesignDesign

FatigueFatigue DiscomfortDiscomfort Illness/InjuryIllness/Injury AbsenteeismAbsenteeism ErrorsErrors Lower productivityLower productivity Customer dissatisfactionCustomer dissatisfaction

Ergonomic Design GoalsErgonomic Design Goals Enhanced Enhanced

performance by performance by eliminating eliminating unnecessary effortunnecessary effort

Reduce Reduce opportunities for opportunities for overexertion overexertion injuryinjury

Improve comfort Improve comfort by curtailing the by curtailing the development of development of fatiguefatigue

Job Demands

Worker Capabilities

"fitting the job task to the person performing the job"

GoalsGoals ImprovedImproved

ProductivityProductivity SafetySafety HealthHealth Job Job

SatisfactionSatisfactionJob Demands

Worker Capabilities

"fitting the job task to the person performing the job"

Dental Ergonomic Dental Ergonomic StressorsStressors

Sustained/awkward posturesSustained/awkward postures Repetitive tasksRepetitive tasks Forceful hand exertionsForceful hand exertions Vibrating operational devicesVibrating operational devices Time pressure from a fixed Time pressure from a fixed

scheduleschedule Coping with patient anxietiesCoping with patient anxieties Precision required with workPrecision required with work

Preventing Ergonomic Preventing Ergonomic InjuriesInjuries

Identify risk factorsIdentify risk factors Educate DHCP about ergonomic Educate DHCP about ergonomic

hazards and preventing MSDshazards and preventing MSDs Identify symptoms as soon as Identify symptoms as soon as

they become apparentthey become apparent Intervene quicklyIntervene quickly

Preventing Ergonomic Preventing Ergonomic Injuries Injuries

Change human behaviorChange human behavior Consider ergonomic features for dental Consider ergonomic features for dental

equipment (e.g., patient chairs, equipment (e.g., patient chairs, operator stools, hand/foot controls, operator stools, hand/foot controls, instruments) when purchasing new instruments) when purchasing new equipmentequipment

Modify working conditions to achieve Modify working conditions to achieve optimal body postureoptimal body posture

Achieve optimum access, visibility, Achieve optimum access, visibility, comfort, and control at all timescomfort, and control at all times

Workplace InterventionWorkplace Intervention ““Make the job fit the person” not Make the job fit the person” not

vice versavice versa Minimize extreme joint positionMinimize extreme joint position

Keep wrist in neutral (i.e., Keep wrist in neutral (i.e., straight) positionstraight) position

Keep joints held at midpoint of Keep joints held at midpoint of range of motionrange of motion

Reduce the use of excess forceReduce the use of excess force Reduce highly repetitive movementReduce highly repetitive movement

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Provide Sufficient SpaceProvide Sufficient Space Awkward bending, twisting, Awkward bending, twisting,

and reaching places stress on and reaching places stress on the musculoskeletal system the musculoskeletal system and can lead to discomfortand can lead to discomfort

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Provide Sufficient SpaceProvide Sufficient Space Permanently place equipment used Permanently place equipment used

in every clinical procedure within in every clinical procedure within comfortable reach (within 20 comfortable reach (within 20 inches of the front of the body)inches of the front of the body)

Use mobile carts for less commonly Use mobile carts for less commonly used equipmentused equipment Allows convenient positioning Allows convenient positioning

when requiredwhen required

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Provide Sufficient SpaceProvide Sufficient Space Provide a clear line of sight to the Provide a clear line of sight to the

oral cavity and all required oral cavity and all required equipmentequipment

Maintain a neutral, balanced Maintain a neutral, balanced position—position—position of an appendage position of an appendage when it is neither moved away from when it is neither moved away from nor directed toward the body’s nor directed toward the body’s midline; it also should not be midline; it also should not be laterally turned or twistedlaterally turned or twisted

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Accommodate Individual Accommodate Individual PreferencesPreferences

Individuals vary in size, shape, Individuals vary in size, shape, training, and experiencetraining, and experience

Ensure equipment and work areas Ensure equipment and work areas allow flexibility; examples may allow flexibility; examples may include:include: Allows right- or left-handed useAllows right- or left-handed use Allows different working posturesAllows different working postures Provides a choice in methods usedProvides a choice in methods used

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Reduce Physical EffortReduce Physical Effort Avoid bent or Avoid bent or

unnatural unnatural posturespostures

Ideally, equipment Ideally, equipment should allow work in a should allow work in a relaxed and well-relaxed and well-balanced positionbalanced position DHCP should adjust DHCP should adjust

equipment to the equipment to the appropriate heightappropriate height

Position the patient Position the patient to allow easy access to allow easy access from the desired from the desired positionposition

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Reduce Physical EffortReduce Physical Effort Use reasonable operating forces and minimal Use reasonable operating forces and minimal

repetitions reduces overall physical effort repetitions reduces overall physical effort required by a taskrequired by a task

Minimize sustained effortMinimize sustained effort Brief but frequent rest pauses can Brief but frequent rest pauses can

minimize fatigue and enhance productivityminimize fatigue and enhance productivity Try to incorporate a variety of different Try to incorporate a variety of different

activities to shift musculoskeletal demands activities to shift musculoskeletal demands from one part of the body to another from one part of the body to another

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Instrument DesignInstrument Design Goal: Goal: reduce force exertion; maintain reduce force exertion; maintain hand/wrist in neutral position (no wrist hand/wrist in neutral position (no wrist bend)bend)

ConsiderationsConsiderations Overall shape/sizeOverall shape/size Handle shape/sizeHandle shape/size WeightWeight BalanceBalance ManeuverabilityManeuverability Ease of operationEase of operation Ease of maintenanceEase of maintenance

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Hand InstrumentsHand Instruments When selecting instruments look When selecting instruments look

forfor Hollow or resin handlesHollow or resin handles Round, textured/grooves, or Round, textured/grooves, or

compressible handlescompressible handles Carbon-steel constructionCarbon-steel construction Color-coding may make Color-coding may make

instrument identification easierinstrument identification easier

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Dental HandpiecesDental Handpieces When selecting handpieces look forWhen selecting handpieces look for

Lightweight, balanced models Lightweight, balanced models Sufficient powerSufficient power Built-in light sourcesBuilt-in light sources Angled vs. straight-shankAngled vs. straight-shank Pliable, lightweight hoses (extra Pliable, lightweight hoses (extra length adds weight)length adds weight) Swivel mechanismsSwivel mechanisms Easy activationEasy activation Easy maintenanceEasy maintenance

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Syringes and DispenserSyringes and Dispenser When selecting look forWhen selecting look for

Adequate lumen sizeAdequate lumen size Ease in cleaningEase in cleaning Textured/grooved handles Textured/grooved handles Easy activation and placementEasy activation and placement

Applying Ergonomics to Applying Ergonomics to DentistryDentistryLightingLighting

Goal: produce even, shadow-Goal: produce even, shadow-free, color-corrected free, color-corrected illumination concentrated on illumination concentrated on operating fieldoperating field

Overhead light switch readily Overhead light switch readily accessibleaccessible

Hand mirrors can be used to Hand mirrors can be used to provide light intraorallyprovide light intraorally

Fiberoptics for handpieces add Fiberoptics for handpieces add concentrated lighting to the concentrated lighting to the operating fieldoperating field

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Magnification Magnification Goal: improve neck posture; provide clearer Goal: improve neck posture; provide clearer

visionvision When selecting magnification systems When selecting magnification systems

considerconsider Working distanceWorking distance Depth of fieldDepth of field Declination angleDeclination angle Convergence angleConvergence angle Magnification factorMagnification factor Lighting needsLighting needs

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Operator ChairOperator Chair Goal: promote mobility and patient Goal: promote mobility and patient

access; accommodate different body access; accommodate different body sizessizes

Look for:Look for: Stability Stability Lumbar supportLumbar support Hands-free seat height Hands-free seat height

adjustmentadjustment Fully adjustableFully adjustable

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Patient ChairPatient Chair Goal: promote patient comfort; maximize Goal: promote patient comfort; maximize

patient accesspatient access Look for:Look for:

Stability Stability Pivoting or drop-down Pivoting or drop-down

arm rests (for patient arm rests (for patient

ingress/egress)ingress/egress) Fully adjustable head restFully adjustable head rest Hands-free operationHands-free operation

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Posture/PositioningPosture/Positioning Goal: avoid static and/or awkward Goal: avoid static and/or awkward

positionspositions Potential strategiesPotential strategies

Position patient so that Position patient so that operator’s elbows are elevated operator’s elbows are elevated no more than 30 degreesno more than 30 degrees

Adjust patient chair when Adjust patient chair when accessing different quadrantsaccessing different quadrants

Alternate between standing and Alternate between standing and sitting sitting

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Work PracticesWork Practices Goal: maintain neutral posture; reduce Goal: maintain neutral posture; reduce

force requirementsforce requirements Potential strategiesPotential strategies

Ensure instruments are sharpened, Ensure instruments are sharpened, well-maintainedwell-maintained

Use automatic handpieces instead of Use automatic handpieces instead of manual instruments wherever possiblemanual instruments wherever possible

Use full-arm strokes rather than wrist Use full-arm strokes rather than wrist strokes strokes

Applying Ergonomics to Applying Ergonomics to DentistryDentistrySchedulingScheduling

Goal: provide sufficient recovery time Goal: provide sufficient recovery time to avoid muscular fatigueto avoid muscular fatigue

Potential strategiesPotential strategies Increase treatment time for more Increase treatment time for more

difficult patientsdifficult patients Alternate heavy and light calculus Alternate heavy and light calculus

patients within a schedulepatients within a schedule Vary procedures within the same Vary procedures within the same

appointmentappointment Shorten patient’s recall intervalShorten patient’s recall interval

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Personal Protective EquipmentPersonal Protective Equipment GlassesGlasses

Lightweight, clean, well-fittedLightweight, clean, well-fitted Magnifying lenses and head Magnifying lenses and head

lamps are encouragedlamps are encouraged ClothingClothing

Fit loosely, lightweight, pliableFit loosely, lightweight, pliable

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Personal Protective EquipmentPersonal Protective Equipment GlovesGloves

Be of proper size, lightweight, and Be of proper size, lightweight, and pliablepliable

Should fit hands and fingers snuglyShould fit hands and fingers snugly Should not fit tightly across Should not fit tightly across

wrist/forearm wrist/forearm

Applying Ergonomics to Applying Ergonomics to DentistryDentistry

Personal Protective EquipmentPersonal Protective Equipment GlovesGloves

Ambidextrous (i.e., non-hand specific): Ambidextrous (i.e., non-hand specific): exert more force than fitted gloves exert more force than fitted gloves across palmar region of hand and may across palmar region of hand and may exacerbate symptoms of carpal tunnel exacerbate symptoms of carpal tunnel syndromesyndrome

Hand-specific (i.e., right vs left) is Hand-specific (i.e., right vs left) is recommendedrecommended Fit betterFit better Place less force on handPlace less force on hand

ReferencesReferences Ergonomics and Disability Support Advisory Committee (EDSAC) to the Ergonomics and Disability Support Advisory Committee (EDSAC) to the

Council on Dental Practice (CDP). An introduction to ergonomics: risk Council on Dental Practice (CDP). An introduction to ergonomics: risk factors, MSDs, approaches and interventions. American Dental factors, MSDs, approaches and interventions. American Dental Association;2004.Association;2004.

Grant KA. Ergonomics: is it optional? PowerPoint presentation. Grant KA. Ergonomics: is it optional? PowerPoint presentation. Murphy DC. Ergonomics and the Dental Care Worker. American Public Murphy DC. Ergonomics and the Dental Care Worker. American Public

Health Association, United Book Press, Washington, DC;1998.Health Association, United Book Press, Washington, DC;1998. NIOSH. Work-related musculoskeletal disorders. 1997.NIOSH. Work-related musculoskeletal disorders. 1997. SmartTec. Musculoskeletal disorders: their symptoms and possible SmartTec. Musculoskeletal disorders: their symptoms and possible

causes. Smartpractice;2002.causes. Smartpractice;2002.