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USAF Dental Evaluation & Consultation ServiceUSAF Dental Evaluation & Consultation Service

Musculoskeletal Disordersand Ergonomics in

Dentistry:

An Introduction

Course Date: 5/06Reviewed/Updated: 10/10

Expiration Date: 10/13

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ObjectivesObjectives

Provide information onProvide information onmusculoskeletal disorders in dentalmusculoskeletal disorders in dentalhealthhealth--care personnel.care personnel.

ProvideProvide information on ergonomicsinformation on ergonomicsfor dental healthfor dental health--care personnel.care personnel.


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Musculoskeletal DisordersMusculoskeletal Disorders

(MSDs)(MSDs) Include a group of conditions thatInclude a group of conditions that

involve nerves, tendons, muscles,involve nerves, tendons, muscles,

and supporting structures such asand supporting structures such asintervertebral discsintervertebral discs

Severity of Symptoms

Mild periodic Severe chronic &debilitating conditions

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MSDsMSDs == ErgonomicsErgonomics Musculoskeletal problems are theMusculoskeletal problems are the

problem and ergonomics is aproblem and ergonomics is a

solution.solution.

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Types of MSDsTypes of MSDs Neck and ShoulderNeck and Shoulder

DisordersDisorders Myofascial PainMyofascial Pain

DisorderDisorder

Cervical SpondylolysisCervical Spondylolysis Thoracic OutletThoracic Outlet

SyndromeSyndrome

Rotator CuffRotator CuffTendinitis/TearsTendinitis/Tears

Back DisordersBack Disorders Herniated Spinal DiscHerniated Spinal Disc

Lower Back PainLower Back Pain

SciaticaSciatica

Hand and WristHand and WristDisordersDisorders DeQuervains DiseaseDeQuervains Disease Trigger FingerTrigger Finger Carpal TunnelCarpal Tunnel

SyndromeSyndrome Guyons SyndromeGuyons Syndrome Cubital TunnelCubital Tunnel

SyndromeSyndrome HandHand--Arm VibrationArm Vibration

SyndromeSyndrome Raynauds PhenomenonRaynauds Phenomenon

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MSDsMSDs

Signs SymptomsSigns Symptoms

Decreased rangeDecreased rangeof motionof motion

DeformityDeformity

Decreased gripDecreased gripstrengthstrength

Loss of muscleLoss of musclefunctionfunction

PainPain

N

umb

nessN

umb

ness TinglingTingling

BurningBurning

CrampingCramping StiffnessStiffness

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Contributing Factors forContributing Factors forWorkWork--Related MSDsRelated MSDs

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

Forceful hand exertionsForceful hand exertions Repetitive movementsRepetitive movements Fixed or awkward posturesFixed or awkward posturesVibrating toolsVibrating tools Unassisted frequent or heavy liftingUnassisted frequent or heavy lifting

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What Factors Contribute toWhat Factors Contribute to

WMSDs?WMSDs? Forceful hand exertionsForceful hand exertions

Grasping small instruments for prolongedGrasping small instruments for prolongedperiodsperiods

Forceful squeezing/release of instrumentsForceful squeezing/release of instruments

Repetitive movementsRepetitive movementse.g., scaling,e.g., scaling,root planing, polishingroot planing, polishing

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WMSDs?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

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WMSDs?WMSDs? Prolonged use of vibrating handProlonged use of vibrating hand

toolstoolsdental handpieces, laboratorydental handpieces, laboratory

equipmentequipment

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Contributing Factors forContributing Factors for

WMSDsWMSDs A risk factor is not always a causationA risk factor is not always a causation

factorfactor

The level of risk depends onThe level of risk depends on Length of time a worker is exposedLength of time a worker is exposed

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

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

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WMSDsWMSDs Do not focus solely on the workplaceDo not focus solely on the workplace

Risk factors may be experiencedRisk factors may be experiencedduring nonduring non--occupational activitiesoccupational activities

(e.g., certain sports, exercising,(e.g., certain sports, exercising,working with computers, needlework,working with computers, needlework,playing musical instruments)playing musical instruments)

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WMSDsWMSDs Not everyone exposed to any or all ofNot everyone exposed to any or all of

the risk factors will develop a MSDthe risk factors will develop a MSD

Individuals do not respond to them inIndividuals do not respond to them inthe same waythe same way Predisposing factors such as age,Predisposing factors such as age,

arthritis, renal disease, hormonalarthritis, renal disease, hormonal

imbalances, diabetes, andimbalances, diabetes, andhypothyroidism may play a rolehypothyroidism may play a role

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Neck and ShoulderNeck and Shoulder

DisordersDisorders Risk factors associated with dentistryRisk factors associated with dentistry

Prolonged static neck flexion andProlonged static neck flexion andshoulder abduction or flexionshoulder abduction or flexion

Lack of upperLack of upper--extremity supportextremity support

Inadequate work breaksInadequate work breaks

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DisordersDisorders Dental healthDental health--care personnel (DHCP)care personnel (DHCP)

commonly assume awkward workcommonly assume awkward workposturespostures To obtain better views of the intraoralTo obtain better views of the intraoral

cavitycavity To provide a more comfortable position forTo provide a more comfortable position for

the patientthe patient

To coordinate their position relative to theTo coordinate their position relative to thedentist or assistantdentist or assistant While operating equipment and reachingWhile operating equipment and reaching

for instruments and suppliesfor instruments and supplies

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DisordersDisorders ExamplesExamples

Myofascial Pain DisorderMyofascial Pain Disorder

Cervical SpondylolysisCervical Spondylolysis

Thoracic Outlet SyndromeThoracic Outlet Syndrome

Rotator Cuff Tendinitis/TearsRotator Cuff Tendinitis/Tears

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Neck and Shoulder DisordersNeck and Shoulder Disorders

Myofascial Pain DisorderMyofascial Pain Disorder

Pain and tenderness in the neck,Pain and tenderness in the neck,

shoulder, arm musclesshoulder, arm muscles Painful trigger pointsPainful trigger pointsmay twitchmay twitch

upon touch or massageupon touch or massage

Restricted range of motionRestricted range of motion

Possible causes: overloadedPossible causes: overloadedneck/shoulder musclesneck/shoulder muscles

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Neck and ShoulderNeck and ShoulderDisordersDisorders

Cervical SpondylosisCervical Spondylosis

Intermittent/chronic neck and shoulderIntermittent/chronic neck and shoulder

pain or stiffnesspain or stiffness HeadacheHeadache Hand and arm pain, numbness, tingling,Hand and arm pain, numbness, tingling,

clumsiness may occurclumsiness may occur Possible causes: agePossible causes: age--related spinal discrelated spinal disc

degeneration leading to nervedegeneration leading to nervecompression and spinal cord damage;compression and spinal cord damage;arthritisarthritis

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Thoracic Outlet SyndromeThoracic Outlet Syndrome

Pain in the shoulder, arm or hand (can bePain in the shoulder, arm or hand (can be

all three)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 orPossible causes: compressed nerves orblood vessels passing into arms; trauma;blood vessels passing into arms; trauma;slouching forward or dropping shouldersslouching forward or dropping shoulders

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Rotator Cuff Tendinitis/TearsRotator Cuff Tendinitis/Tears

Pain and stiffness in the shoulderPain and stiffness in the shoulder

associated with backward andassociated with backward andupward arm movementsupward arm movements

Weakness of rotator cuff musclesWeakness of rotator cuff muscles

Possible causes: swelling or tearingPossible causes: swelling or tearingof rotator cuff soft tissue; shoulderof rotator cuff soft tissue; shoulderjoint bone spurs/abnormalities; poorjoint bone spurs/abnormalities; poorshoulder postureshoulder posture

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

Chronic repetitive movements of theChronic repetitive movements of thehand and wristhand and wrist

Abnormal or awkward positions of theAbnormal or awkward positions of thewristwrist

Mechanical stresses to digital nervesMechanical stresses to digital nervessuch as sustained grasps onsuch as sustained grasps on

instrument handlesinstrument handles Forceful workForceful work

Extended use of vibratory instrumentsExtended use of vibratory instruments

Inadequate work breaksInadequate work breaks

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Hand and Wrist DisordersHand and Wrist Disorders

ExamplesExamples DeQuervains DiseaseDeQuervains Disease

Trigger FingerTrigger Finger Carpal Tunnel SyndromeCarpal Tunnel Syndrome

Guyons SyndromeGuyons Syndrome

Cub

italT

unnel SyndromeCub

italT

unnel Syndrome HandHand--Arm Vibration SyndromeArm Vibration Syndrome

Raynauds PhenomenonRaynauds Phenomenon

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Hand and Wrist DisordersHand and Wrist DisordersDeQuervains DiseaseDeQuervains Disease

Pain in thumb and wrist area whenPain in thumb and wrist area whengrasping, pinching, twistinggrasping, pinching, twisting

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

with painwith pain Possible causes: synovial sheathPossible causes: synovial sheath

swelling; thickening of tendons atswelling; thickening of tendons atbase of thumb; repeated trauma orbase of thumb; repeated trauma ortwisting hand/wrist motionstwisting hand/wrist motions

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Trigger Finger (Tenosynovitis)Trigger Finger (Tenosynovitis)

Pain during movement that placePain during movement that place

tendons in tensiontendons in tension Warmth, swelling, tenderness of theWarmth, swelling, tenderness of the

tendon when palpatedtendon when palpated

Possible causes: sustained, forcefulPossible causes: sustained, forceful

powerful grip and/or repetitivepowerful grip and/or repetitivemotionmotion

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Carpal Tunnel SyndromeCarpal Tunnel Syndrome 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 atPain or tingling that awakens the patient atnight with relief via shaking/massaging thenight with relief via shaking/massaging thehand is considered a hallmark symptom forhand is considered a hallmark symptom for

diagnosisdiagnosis Possible causes: compressed median nerve inPossible causes: compressed median nerve in

wrist via trauma, forceful exertion, repetitivewrist via trauma, forceful exertion, repetitiveand awkward movements that deviate fromand awkward movements that deviate fromnearnear--neutral positionsneutral positions

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Hand and Wrist DisordersHand and Wrist DisordersCarpal Tunnel SyndromeCarpal Tunnel Syndrome

All hand pain does not mean carpalAll hand pain does not mean carpaltunnel syndrometunnel syndrome

DHCP do not appear to be atDHCP do not appear to be atgreater risk compared to thegreater risk compared to thegeneral population for developinggeneral population for developingcarpal tunnel syndromecarpal tunnel syndrome

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 mononeuropathyPrevalence of carpal tunnel syndrome and median mononeuropathyamong dentists. J Am Dent Assoc 2001;132:163among dentists. J Am Dent Assoc 2001;132:163--170.170.

Werner RA, Hamann C, Franzblau A, Rodgers PA. Prevalence of carpalWerner RA, Hamann C, Franzblau A, Rodgers PA. Prevalence of carpaltunnel syndrome and upper extremity tendinitis among dentaltunnel syndrome and upper extremity tendinitis among dentalhygienists. J Dent Hyg 2002;76:126hygienists. J Dent Hyg 2002;76:126--132.132.

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Hand and Wrist DisordersHand and Wrist DisordersGuyons SyndromeGuyons Syndrome

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

ring fingerring finger Symptoms may worsen at night or earlySymptoms may worsen at night or early

morningmorning

Possible causes: compressed ulnar nervePossible causes: compressed ulnar nervein Guyons canal at the base of the palm;in Guyons canal at the base of the palm;repetitive wrist flexing; excessive pressurerepetitive wrist flexing; excessive pressureon palm/base of handon palm/base of hand

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Cubital Tunnel SyndromeCubital Tunnel Syndrome

Pain, numbness, tingling and impairedPain, numbness, tingling and impaired

sense of touch in the little and ring fingers,sense of touch in the little and ring fingers,side and back of handside and back of hand

Loss of fine controlLoss of fine control

Reduced grip strengthReduced grip strength

Possible causes: compressed ulnar nervePossible causes: compressed ulnar nervein elbow due to trauma or repeated use;in elbow due to trauma or repeated use;prolonged use of elbow while flexedprolonged use of elbow while flexed

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Hand and Wrist DisordersHand and Wrist DisordersHandHand--Arm Vibration SyndromeArm Vibration Syndrome

Intermittent or chronic finger and handIntermittent or chronic finger and handnumbness and blanchingnumbness and blanching

Reduced dexterity, grip strength, andReduced dexterity, grip strength, andsensationsensation

Greater sensitivity to coldGreater sensitivity to cold

Possible causes: vibrations may injurePossible causes: vibrations may injure

nerves leading to decreased blood flownerves leading to decreased blood flowand lower oxygen supply to surroundingand lower oxygen supply to surroundingtissuestissues

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Raynauds PhenomenonRaynauds Phenomenon Intermittent spasm of finger and toe bloodIntermittent spasm of finger and toe blood

vessels causing blanching, numbness, andvessels causing blanching, numbness, and

painpain Increased sensitivity to cold temperaturesIncreased sensitivity to cold temperatures

Possible causes: carpal tunnel syndrome,Possible causes: carpal tunnel syndrome,connective tissue diseases, repeatedconnective tissue diseases, repeated

vibration or use of tools that vibratevibration or use of tools that vibrate

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Back DisordersBack Disorders

Risk factors associated with dentistryRisk factors associated with dentistry

Awkward postureAwkward posture

ExamplesExamples Herniated Spinal DiscHerniated Spinal Disc

Lower Back PainLower Back Pain

SciaticaSciatica

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Herniated Spinal DiscHerniated Spinal Disc Back and leg numbness, tingling, pain,Back and leg numbness, tingling, pain,

weaknessweakness

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

Possible causes: bulging or fragmentingPossible causes: bulging or fragmentingof intervertebral discs into spinal canalof intervertebral discs into spinal canal

compressing and irritating spinalcompressing and irritating spinalnerves; excessive heavy lifting withoutnerves; excessive heavy lifting withoutadequate restadequate rest

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Lower Back PainLower Back Pain PainPain

Stiffness in lower spine andStiffness in lower spine and

surrounding tissuessurrounding tissues Possible causes: heavy lifting andPossible causes: heavy lifting and

forceful movements; whole bodyforceful movements; whole body

vibration; bending/twisting;vibration; bending/twisting;awkward static posturesawkward static postures

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SciaticaSciatica Pain from lower back or hip radiatingPain from lower back or hip radiating

to the buttocks and legsto the buttocks and legs

Leg weakness, numbness, or tinglingLeg weakness, numbness, or tingling Possible causes: prolapsedPossible causes: prolapsed

intervertebral disc pressuring theintervertebral disc pressuring thesciatic nerve; worsened withsciatic nerve; worsened with

prolonged sitting or excessiveprolonged sitting or excessivebending/liftingbending/lifting

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Treatment and Management ofTreatment and Management of

MSDsMSDs Obtain an accurate diagnosis from aObtain an accurate diagnosis from a

qualified healthqualified health--care providercare provider

Early intervention is keyEarly intervention is key SelfSelf--diagnosis is not recommendeddiagnosis is not recommended

MSD origins are complex with a broadMSD origins are complex with a broadrange of symptomsrange of symptoms

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Treatment and Management ofTreatment and Management of

MSDsMSDs Diagnostic tests may include physicalDiagnostic tests may include physical

exams, provocative tests, andexams, provocative tests, and

electromyographyelectromyography Treatment may range from painTreatment may range from pain--reliefrelief

medications and rest to surgery, andmedications and rest to surgery, andergonomic interventions both at workergonomic interventions both at workand homeand home

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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 preventingErgonomics is much broader than preventing

workwork--related musculoskeletal disordersrelated musculoskeletal disorders

Ergonomics plays an important role inErgonomics plays an important role inpreventing injury and illnesspreventing injury and illness

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What is Ergonomics?What is Ergonomics?

An applied scienceAn applied scienceconcerned withconcerned withdesigning anddesigning and

arranging thingsarranging thingspeople use so thatpeople use so thatthe people andthe people andthings interactthings interactmost efficientlymost efficientlyand safelyand safely

Job Demands

WorkerCapabilities

"fitting the job task to theperson performing the job"

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Consequences of PoorConsequences of Poor

DesignDesign FatigueFatigue

DiscomfortDiscomfort

Illness/InjuryIllness/Injury

AbsenteeismAbsenteeism

ErrorsErrors Lower productivityLower productivity

Customer dissatisfactionCustomer dissatisfaction

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Ergonomic Design GoalsErgonomic Design Goals

EnhancedEnhancedperformance byperformance byeliminatingeliminatingunnecessary effortunnecessary effort

ReduceReduceopportunities foropportunities foroverexertion injuryoverexertion injury

Improve comfort byImprove comfort by

curtailing thecurtailing thedevelopment ofdevelopment offatiguefatigue

Job Demands

WorkerCapabilities


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GoalsGoals

ImprovedImproved ProductivityProductivity SafetySafety HealthHealthJob SatisfactionJob Satisfaction Job Demands

WorkerCapabilities


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Dental Ergonomic StressorsDental Ergonomic Stressors

Sustained/awkward posturesSustained/awkward postures

Repetitive tasksRepetitive tasks

Forceful hand exertionsForceful hand exertions

Vibrating operational devicesVibrating operational devices

Time pressure from a fixed scheduleTime pressure from a fixed schedule

Coping with patient anxietiesCoping with patient anxieties

Precision required with workPrecision required with work

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Preventing ErgonomicPreventing Ergonomic

InjuriesInjuries Identify risk factorsIdentify risk factors

Educate DHCP about ergonomicEducate DHCP about ergonomichazards and preventing MSDshazards and preventing MSDs

Identify symptoms as soon as theyIdentify symptoms as soon as theybecome apparentbecome apparent

Intervene quicklyIntervene quickly

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Preventing ErgonomicPreventing Ergonomic

InjuriesInjuries Change human behaviorChange human behavior

Consider ergonomic features for dentalConsider ergonomic features for dental

equipment (e.g., patient chairs, operatorequipment (e.g., patient chairs, operatorstools, hand/foot controls, instruments)stools, hand/foot controls, instruments)when purchasing new equipmentwhen purchasing new equipment

Modify working conditions to achieveModify 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

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Workplace InterventionWorkplace Intervention

Make the job fit the person not viceMake the job fit the person not viceversaversa

Minimize extreme joint positionMinimize extreme joint position

Keep wrist in neutral (i.e., straight)Keep wrist in neutral (i.e., straight)positionposition

Keep joints held at midpoint of rangeKeep joints held at midpoint of rangeof motionof motion

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

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Applying Ergonomics to DentistryApplying Ergonomics to Dentistry

Provide Sufficient SpaceProvide Sufficient SpaceAwkward bending, twisting, andAwkward bending, twisting, and

reaching places stress on thereaching places stress on the

musculoskeletal system and canmusculoskeletal system and canlead to discomfortlead to discomfort

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Provide Sufficient SpaceProvide Sufficient Space

Permanently place equipment used inPermanently place equipment used inevery clinical procedure withinevery clinical procedure withincomfortable reach (within 20 inches ofcomfortable reach (within 20 inches ofthe front of the body)the front of the body)

Use mobile carts for less commonlyUse mobile carts for less commonly

used equipmentused equipment

Allows convenient positioning whenAllows convenient positioning whenrequiredrequired

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Provide Sufficient SpaceProvide Sufficient Space

Provide a clear line of sight to the oralProvide a clear line of sight to the oralcavity and all required equipmentcavity and all required equipment

Maintain a neutral, balanced positionMaintain a neutral, balanced positionposition of an appendage when it isposition of an appendage when it isneither moved away from nor directedneither moved away from nor directed

toward the bodys midline; it alsotoward the bodys midline; it alsoshould not be laterally turned orshould not be laterally turned ortwistedtwisted

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Accommodate Individual PreferencesAccommodate Individual Preferences

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

Ensure equipment and work areasEnsure equipment and work areasallow flexibility; examples may include:allow flexibility; examples may include:

Allows rightAllows right-- or leftor left--handed usehanded use

Allows different working posturesAllows different working postures

Provides a choice in methods usedProvides a choice in methods used

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Reduce Physical EffortReduce Physical Effort Avoid bent orAvoid bent or

unnatural posturesunnatural postures Ideally, equipmentIdeally, equipment

should allow work inshould allow work in

a relaxed and wella relaxed and well--balanced positionbalanced position

DHCP should adjustDHCP should adjustequipment to theequipment to the

appropriate heightappropriate height Position the patientPosition the patient

to allow easy accessto allow easy accessfrom the desiredfrom the desired

positionposition

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Reduce Physical EffortReduce Physical Effort

Use reasonable operating forces and minimalUse reasonable operating forces and minimalrepetitions reduces overall physical effortrepetitions reduces overall physical effort

required by a taskrequired by a task Minimize sustained effortMinimize sustained effort

Brief but frequent rest pauses canBrief but frequent rest pauses can

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

activities to shift musculoskeletal demandsactivities to shift musculoskeletal demandsfrom one part of the body to anotherfrom one part of the body to another

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Applying Ergonomics to DentistryApplying Ergonomics to DentistryInstrument DesignInstrument Design

Goal:Goal: reduce force exertion; maintainreduce force exertion; maintainhand/wrist in neutral position (nohand/wrist in neutral position (nowrist bend)wrist 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

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Hand InstrumentsHand Instruments

When selecting instruments, look forWhen selecting instruments, look for

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

compressible handlescompressible handles

CarbonCarbon--steel constructionsteel construction ColorColor--coding may make instrumentcoding may make instrument

identification easieridentification easier

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Applying Ergonomics to DentistryApplying Ergonomics to DentistryDental HandpiecesDental Handpieces

When selecting handpieces, look forWhen selecting handpieces, look for

Lightweight, balanced modelsLightweight, balanced models

Sufficient powerSufficient power

BuiltBuilt--in light sourcesin light sourcesAngled vs. straightAngled vs. straight--shankshank

Pliable, lightweight hoses (extraPliable, lightweight hoses (extra

length adds weight)length adds weight)

Swivel mechanismsSwivel mechanisms Easy activationEasy activation

Easy maintenanceEasy maintenance

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Syringes and DispenserSyringes and Dispenser

When selecting look forWhen selecting look for

Adequate lumen sizeAdequate lumen size Ease in cleaningEase in cleaning

Textured/grooved handlesTextured/grooved handles

Easy activation and placementEasy activation and placement

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LightingLighting Goal: produce even, shadowGoal: produce even, shadow--

free, colorfree, color--correctedcorrectedillumination concentrated onillumination concentrated onoperating fieldoperating field

Overhead light switch readilyOverhead light switch readilyaccessibleaccessible

Hand mirrors canb

e used toHand mirrors canb

e used toprovide light intraorallyprovide light intraorally

Fiberoptics for handpieces addFiberoptics for handpieces addconcentrated lighting to theconcentrated lighting to theoperating fieldoperating field

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MagnificationMagnification Goal: improve neck posture; provideGoal: improve neck posture; provide

clearer visionclearer vision

When selecting magnification systemsWhen selecting magnification systemsconsiderconsider

Working distanceWorking distance

Depth of fieldDepth of field

Declination angleDeclination angle

Convergence angleConvergence angle

Magnification factorMagnification factor

Lighting needsLighting needs

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

accommodate different body sizesaccommodate different body sizes

Look for:Look for: StabilityStability

Lumbar supportLumbar support

HandsHands--free seat heightfree seat heightadjustmentadjustment

Fully adjustableFully adjustable

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

patient accesspatient access

Look for:Look for: StabilityStability

Pivoting or dropPivoting or drop--downdown

arm rests (for patientarm rests (for patientingress/egress)ingress/egress)

Fully adjustable head restFully adjustable head rest

HandsHands--free operationfree operation

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

positionspositions

Potential strategiesPotential strategies Position patient so that operatorsPosition patient so that operators

elbows are elevated no more thanelbows are elevated no more than30 degrees30 degrees

Adjust patient chair when accessingAdjust patient chair when accessingdifferent quadrantsdifferent quadrants

Alternate between standing andAlternate between standing andsittingsitting

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

force requirementsforce requirements

Potential strategiesPotential strategies Ensure instruments are sharpened,Ensure instruments are sharpened,

wellwell--maintainedmaintained

Use automatic handpieces instead ofUse automatic handpieces instead ofmanual instruments wherever possiblemanual instruments wherever possible

Use fullUse full--arm strokes rather than wristarm strokes rather than wriststrokesstrokes

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SchedulingScheduling Goal: provide sufficient recovery time toGoal: provide sufficient recovery time to

avoid muscular fatigueavoid muscular fatigue Potential strategiesPotential strategies

Increase treatment time for moreIncrease treatment time for moredifficult patientsdifficult patients

Alternate heavy and light calculusAlternate heavy and light calculuspatients within a schedulepatients within a schedule

Vary procedures within the sameVary procedures within the sameappointmentappointment

Shorten patients recall intervalShorten patients recall interval

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Personal Protective EquipmentPersonal Protective Equipment GlassesGlasses

Lightweight, clean, wellLightweight, clean, well--fittedfitted

Magnifying lenses and head lampsMagnifying lenses and head lampsare encouragedare encouraged

ClothingClothing

Fit loosely, lightweight, pliableFit loosely, lightweight, pliable

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Personal Protective EquipmentPersonal Protective Equipment GlovesGloves

Be of proper size, lightweight, and pliableBe of proper size, lightweight, and pliable

Should fit hands and fingers snuglyShould fit hands and fingers snugly Should not fit tightly across wrist/forearmShould not fit tightly across wrist/forearm

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Personal Protective EquipmentPersonal Protective Equipment GlovesGloves

Ambidextrous (i.e., nonAmbidextrous (i.e., non--hand specific): exerthand specific): exertmore force than fitted gloves across palmarmore force than fitted gloves across palmarregion of hand and may exacerbateregion of hand and may exacerbatesymptoms of carpal tunnel syndromesymptoms of carpal tunnel syndrome

HandHand--specific (i.e., right vs left) isspecific (i.e., right vs left) isrecommendedrecommended

Fit betterFit better

Place less force on handPlace less force on hand

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ReferencesReferences

Ergonomics and Disability Support AdvisoryErgonomics and Disability Support AdvisoryCommittee (EDSAC) to the Council on DentalCommittee (EDSAC) to the Council on DentalPractice (CDP). An introduction to ergonomics: riskPractice (CDP). An introduction to ergonomics: riskfactors, MSDs, approaches and interventions.factors, MSDs, approaches and interventions.American Dental Association;2004.American Dental Association;2004.

Grant KA. Ergonomics: is it optional? PowerPointGrant KA. Ergonomics: is it optional? PowerPointpresentation.presentation.

Murphy DC. Ergonomics and the Dental CareMurphy DC. Ergonomics and the Dental CareWorker. American Public Health Association, UnitedWorker. American Public Health Association, UnitedBook Press, Washington, DC;1998.Book Press, Washington, DC;1998.

NIOSH. WorkNIOSH. Work--related musculoskeletal disorders.related musculoskeletal disorders.1997.1997.

SmartTec. Musculoskeletal disorders: theirSmartTec. Musculoskeletal disorders: theirsymptoms and possible causes. Smartpractice;2002.symptoms and possible causes. Smartpractice;2002.

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