بسم الله الرحمن الرحيم

Mechanisms leading to musculoskeletal disorders

in dentistry

What Factors Contribute to What Factors Contribute to WMSDsWMSDs??

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

WMSD Symptoms WMSD Symptoms Among Dental Among Dental HygienistsHygienists

01020304050607080

*DiagnosedCTS

*Hand-wristpain

*Shoulderpain

*Neck pain Low Backpain

% R

epo

rtin

g

Dental Hygienists Dental Assistants

Source: Liss et al., 1995* indicates difference is significant

Prevalence of musculoskeletal disorders among orthodontists in Alberta

0

10

20

30

40

50

60

LBP shoulder

Male

Female

Neck

In a 1946 study, Biller found operators.

0

20

40

60

80

LBP

196419901996

What Factors Contribute to What Factors Contribute to WMSDsWMSDs??

Fixed or awkward Fixed or awkward posturespostures Neck, back, shoulder Neck, back, shoulder

postureposture Hand/wrist positionsHand/wrist positions Standing/sittingStanding/sitting Operatory organizationOperatory organization Patient positioningPatient positioning

When operators sit, pain occurs not only in their backs, but also their necks, shoulders and arms.

operators who primarily stood experienced low back pain (65.7 percent), as well as neurocirculatory disease including varicose veins (66.7 percent), postural defects (77 percent) and flatfoot (60.1 percent).

Contributing Factors for Contributing Factors for WMSDsWMSDs

Do not focus solely on the workplaceDo not focus solely on the workplace Risk factors may be experienced Risk factors may be experienced

during non-occupational activities during non-occupational 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)

Neck and Shoulder Neck and Shoulder DisordersDisordersbahu dan leherbahu dan leher gangguangangguan

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

MUSCLE IMBALANCES

Forward bending Repeated rotation of the head, neck

and trunk to one side Over time, the muscles responsible

for rotating the body to one side can become stronger and shorter, while the opposing muscles become weaker and elongated

lengtheninglengthening

shorteningshortening

lengthening or shortening

muscle imbalance

muscle imbalance

ketidakseimbangan otot

ketidakseimbangan otot

Pectoralis minor Shortening