The document discusses the importance of ergonomics in dentistry, highlighting how poor ergonomic practices can lead to musculoskeletal disorders (MSDs) in dental professionals. It covers the definition of ergonomics, common injuries, and preventative measures, including tool design and proper workstation setup. Additionally, it emphasizes the benefits of ergonomically designed furniture and instruments to enhance practitioner comfort and reduce the risk of long-term injuries.

1. ERGONOMICS IN
DENTISTRY
Dr. Sushmita Rane
MDS III
Seminar 11
17/1/2024

2. CONTENTS:
Introduction
Definition
Ergonomic Design Goals
Musculoskeletal Disorders
Application of ergonomics in dentistry
Four handed Dentistry
Conclusion
References

3. INTRODUCTION

"Look after your body Jim Rohn says, "It's the only place
where you reside”.
Dental professionals are susceptible to a variety of occupational
diseases and disorders, the most frequent of which being
Musculoskeletal Disorders (MSDs), which can cause longterm
harm.
The most prevalent injuries are to the wrists, elbows, shoulders,
neck, and back and spine, according to research.

5. Ergonomics is derived from two Greek words: Ergon, which means
"labour," and Nomo’s, which means "principles or laws”.
It is a method of working smarter by providing tools, equipment, and
workstations that allow practitioners to operate as efficiently and
safely as possible. Ergonomic design improves productivity, reduces
injuries, and increases worker happiness.
The International Ergonomics Association (IEA) defines ergonomics
(or human factors) as “the scientific discipline concerned with the
understanding of the interactions among humans and other elements
of a system, and the profession that applies theoretical principles,
data and methods to design, in order to optimize human well-being
and overall system performance.”

6. WHAT BAD POSTURE CAN CAUSE ?
The potential to develop
musculoskeletal disorders is
higher when one disregards
good ergonomic principles. In
doing so, dentists are at risk of
compromising their technical
expertise during procedures.
This can lead to a limitation
of certain procedures,
potential career shortening,
and, in the worst case, possible
career-ending injuries.

7. The surveys below show that the main complaints are neck and lower
back pain. It has also been noted that female dentists appear to have a
higher incidence of upper body complaints than their male
counterparts.

8. ERGONOMIC DESIGN GOALS
Improve job process by
eliminating unnecessary
tasks, steps and efforts
Reduce potential for
overexertion injury
Minimize
mental/physical fatigue
potential
Leverage worker’s
skill/knowledge of their
jobs to increase their
satisfaction, comfort
and fulfillment

9. CONSEQUENCES OF POOR DESIGN
Discomfort Chronic pain
Accidents Injuries
Fatigue Increased Errors
Work related Musculoskeletal Disorders:
-Lower back pain
-Tendinitis
-Epicondylitis
-Carpel tunnel syndrome

11. MUSCULOSKELETAL DISORDERS (MSDS)–
DESCRIPTION AND WIDESPREAD
“Work-related musculoskeletal illnesses with a chronic
progressive development involves ligaments, spinal discs,
muscles, cartilage, nerves, joints and tendons
 known as Repetitive Motion Injuries/RMI or
Cumulative Trauma Disorders/CTD.
 World’s 2nd
leading cause of disability

12. WHY WE SHOULD CARE?
As per an audit of the worldwide dental writing,
around 65% of dental specialists experience outer
muscle manifestations like agony, uneasiness,
practical hindrance, and expanded labour duration.
According to a Bureau of Labour analysis,
dental hygienists scored first among all
professions in terms of the number of
instances of carpel tunnel syndrome per
1,000 employees.

13. RISK FACTORS
1)Long periods of
difficult postures
2) If procedure
performed repeatedly
and over a lengthy
period of time
3) Poor lighting
when the back is bent or twisted
Exercising for long periods of time above
shoulder height
when sitting in a forwardly bent and rotated
position

14. Risk Factors for MSDs Dental Procedures
Repititive motions Scaling and polishing
Awkward Posture Handling of Objects with the back bent/ twisted
Static Posture Static neck, back and shoulders
Forceful exertions Tooth extraction
Duration Grasping small instruments for prolonged periods
Contact Stresses Repeated contacts with hard or sharp objects
Vibration Prolonged use of vibrating hand tools

15. STATIC POSTURES
Researchers have found that even 30 degrees
of forward shoulder flexion or abduction
can cause a significant impairment in blood
circulation within the shoulder / neck region
Static gripping for durations exceeding 20
minutes was also noted during
instrumentation tasks within dental practice.

16. FORCE
Researchers have suggested that excessive use of a pinch
gripping is the greatest contributing risk factor in the
development of MSDs among dental practitioners.
REPETITIVE MOVEMENTS
Highly repetitive tasks like endodontic procedures can lead to
fatigue, tissue damage and discomfort.

17. CLINICAL FEATURES OF MUSCULOSKELETAL DISORDERS
Signs Symptoms
1.
• Range of motion is reduced
2.
• Deprived normal sensation
3.
• Abnormal grip strength
4.
• Loss of normal Locomotion
5.
• Deprived co-ordination.
1.
• Hypersensitivity in hands and
fingers
2.
• Excessive fatigue in shoulder
and neck
3.
• Tingling and burning
sensations in hand
4.
• Weak grip, cramping of hands
5.
• Numbness in fingers and
hands

18. Classification of MSDs
Neural diseases Ulnar neuropathy, Carpal tunnel syndrome.
Diseases of the neck Cervical Spondylosis, Tension Neck Syndrome,
cervical disc disease, Brachial plexus compression.
Diseases of the
shoulder
Trapezius myalgia, Rotator cuff tendonitis,
Rotator cuff tears, and adhesive capsulitis.
Diseases of the
Forearm, Elbow and
Wrist
De Quervains disease, Tendonitis,
Tenosynovitis, Epicondylitis.
Hand-Arm vibration
syndrome
Reynaud’s disease
Diseases of the back Lower Back Pain (LBP), Upper back pain.

19. WRIST
The safest position for the wrist is a straight or neutral position. Special
care should be used to avoid bending the wrist downwards (flexion) or
outwards (ulnar deviation).

20. Carpel Tunnel Syndrome ( CTS)
CTS occurs when the median nerve, which runs from the forearm
into the hand, becomes pressed or squeezed at the wrist.

21. Researchers have highlighted that one of the predictors for the
high prevalence of Carpel Tunnel Syndrome among dentists was
their longer clinical period of repetitive movements
Tendonitis of the Wrist
 Tendonitis of the wrist is accompanied by pain, swelling and
inflammation on the thumb side of the wrist, and is made worse
with grasping and twisting activities .
 People with this disorder have often noted an occasional
“catching” or snapping when moving their thumb.

22. Guyon’s Syndrome
The Compression occurs in this space at
the base of the palm. It is commonly
caused by repetitive wrist flexing or
excessive pressure on palm.
It is characterized by pain, weakness,
numbness, tingling & burning in the
little finger and part of the ring finger.

23. DeQuervain’s Tenosynovitis
This disorder is characterized by pain
and swelling in the thumb and wrist area
when grasping, pinching, twisting, and a
decreased range of motion of thumb with
pain.
This include synovial sheath swelling,
thickening of tendons at base of thumb
Causes- repeated trauma or twisting
hand/wrist motions.

24. Epicondylitis
These Injuries typically occur at either the inside of the elbow,
referred to as Medial Epicondylitis (golfer’s elbow), or outside of the
elbow, known as Lateral Epicondylitis (tennis elbow).

25.  SHOULDERS
Rounding the shoulders can compress
nerves, arteries, and veins that supply
the arm and hand, leading to upper
extremity symptoms.
Poor thoracic
alignment
Slouching
forward
compresses the
chest cavity
Fatigue & loss of
concentration.

26. Trapezius myalgia
Trapezius myalgia (TM) is the complaint of pain,
stiffness, and tightness of the upper trapezius
muscle. It is characterised by acute or persistent
neck-shoulder pain.
trapezius myalgia is caused by static, prolonged
elevation of the shoulders, mental stress, infrequent
breaks, and poor head posture.

27. Rotator Cuff Tear
The rotator cuff (RC) is a group of 4 muscles;
supraspinatus, infraspinatus, teres minor and
subscapularis.
 The Rotator cuff muscle assists with both gross
and fine motor control of the arm.
Research has shown that clinicians who work
without properly fitted loupes lean their neck
forward in an unsupported position 85% of the
time, creating tremendous stress on the neck and
shoulder musculature.

28. Neck
Pain and discomfort are the most common complaints reported in the
neck/shoulder region amongst dental professionals.
The slight inward curve of the neck balances the head on the spine.
Holding the head forward disturbs this balance, straining the joints and
the muscles of the neck and upper back.
This posture also causes compression of the nerves and blood vessels as
they exit the neck, leading to symptoms in the arm and hand.

29. Cervical Spondylosis
This disorder is characterized by intermittent/chronic neck and
shoulder pain or stiffness, headaches, hand and arm pain, numbness,
tingling, and clumsiness.
 Possible causes include age-related spinal disc degeneration leading to
nerve compression and spinal cord damage, arthritis, and time spent
with the neck in sustained awkward postures.

30. The main risk factors associated with dental work are the sustained
awkward postures and poor seating.
 Most individuals with low back pain do not simply injure their back in
one incident but rather gradually over time.

31. Disc Problems
In a seated posture the pressure in the lumbar discs
increases by 50%
During bending (forward flexion) and twisting
(rotation) motions of the spine, the pressure on the
lumbar discs increases by 200%.

32. Sciatica
It is characterized by pain in the lower
back radiating to legs, causing leg
weakness, numbness, or tingling.
 It is commonly caused by bulging,
prolapsed or herniated discs
compressing a spinal nerve root and is
worsened with prolonged sitting or
excessive bending and lifting.

33. INTERVENTION AND PREVENTION
Maintaining a proper posture and symmetry requires a strong connection
between the dentist and the intraoral working zone.
 Ergonomics should be considered while building instruments and
planning workspaces, as well as in clinical practise.
 It is always recommended to leave 35–40 cm between the working field
and the dentist’s eyes
Posture
Instrument
selection
Magnification
and lighting
Dentist
micro
breaks
Scheduling
Dental
personnel
training

34. Maintaining an upright posture should be a priority at all
times.
The following are characteristics of a balanced posture:
•Respect for body symmetry and a straight back.
•Avoid a forward tilt of the body by placing your arms
along your body.
•The operator's feet are symmetrically positioned
Posture
Instrument selection
 When employing devices with dull or blunt
edges, extra force is necessary.
 The adoption of lightweight and durable
mechanical hand pieces should be advocated

35. Shadow-free illumination is
provided by the parallel alignment of
the light beam in the observing
direction, which improves job quality
Magnification and lighting
Dentist micro breaks
Moving the muscular workload from one location
to another should be done on a regular basis.
A dentist can take a break on the chair side and
stretch.

36. to allow for adequate recovery time and to
avoid muscular fatigue.
Develop a patient difficulty rating scale to
ensure difficult treatment
Scheduling
 It ensures that personnel are well
informed about workplace hazards and
are able to selfvolunteer in identifying
and minimising potential hazards
Dental personnel
training

37. SOME ASPECTS OF A FAULTY WORK STATION SET-UP
The dentist’s seat is either excessively high or excessively low.
There is no proper support in a dentist's chair.
The equipment table is incorrectly positioned.
The lighting is inadequate for the work.
Table/work surface edges are sharp and uncomfortable.
The workplace is damp and cold.
Ventilation makes workspace cold.

38. APPLICATIONS OF ERGONOMICS IN DENTISTRY
Work posture
Posture and
vision
Instruments
Dentist
position
Assistant
position
Patient
position Lighting &
magnification
Examination
and control
instruments
Direct &
Indirect
Working
instruments

39. PATIENT CHAIR
Positioning the oral cavity above heart level will increase the rate of shoulder fatigue.
Positioning the oral cavity below the recommended height will result in non-neutral
working postures including over declination of the head, forward and/or lateral bending
of the torso, and inability of the clinician to access free movement in the clock positions.

40. OPERATOR CHAIR
Saddle stool -provides optimal
seating allowing for proper
positioning of the spine and the
pelvis.
The angle of seat allows for proper balance of core
muscles and allows for the maintenance of normal
curvature without the use of a backrest and without
placing stress on the lower spine

41. IDEAL POSTURE OF ORAL HEALTH PROFESSIONAL
THE HEAD
 To be inclined slightly forward, oriented
over the shoulders.
 The interpupillary line is aligned
horizontally not more than 15 to 20
degrees.
TORSO
 The longitudinal axis of the torso is
upright. It promotes the natural curves of
the spine.

42. 7’o clock position
Torso Position : Sit facing the patient with your hip in line with the
patient’s upper arm.
Leg Position : Your thighs should rest against the side of the patient
chair.

43. 9’o Clock Position
Torso Position. Sit facing the side of the
patient’s head. The midline of your torso
is even with the patient’s mouth.
Leg Position. Your legs may be in either
of two acceptable positions: (1) straddling
the patient chair or (2) underneath the
headrest of the patient chair.

44. 11’O CLOCK POSITION
Torso Position. Sit at the top right corner of the
headrest; the midline of your torso is even with the
temple region of the patient’s head.
Leg Position. Your legs should straddle the corner
of the headrest.

45. DIRECT REAR POSITION
Here the dentist sits directly behind the patient
and looks down over the patient’s head
This position is mainly used only working on
lingual surfaces of the mandibular anterior
teeth, lingual surfaces of maxillary anterior
teeth

46. UPPER ARMS, ELBOWS and SHOULDERS
 Arms relaxed at one’s side due to the force of
gravity. The elbows close to the side and the
forearm is in front of the body parallel to the
floor.
WRISTS
 Should be kept in a neutral position with the
wrists straight.
THE FINGERTIPS
 Should be held at the treatment point, at a
height that is comfortable and affords a clear
view of the procedure being performed.

47. SEATED POSTURE
Seating height at knee height; hips slightly higher than
the knees;
tilt the operator stool slightly downward.
THE FEET
To be flat on the floor. The lower legs are in a vertical
position.
Consider comfortable shoes and clothing to ease body
movement.
RHEOSTAT POSITIONING
Place it close to the operator so that the knee is at about
a 90 to 100 degree angle.

48. POSITION OF THE PATIENT
A deliberate patient position should be determined
according to the dentist’s natural posture and his or her
reference point, which allows the clinician to achieve
optimal performance without any physical burden.
Exceptional cases: Treating patients in an upright
position
Occasionally, it may be necessary to treat a patient while
in an upright position, for example during certain
procedures.
elderly patients
complex medical
histories
(hypotension, vertigo)
Pregnancy

49. Patient’s position for Maxillary Arch
Feet
even with or slightly
higher than the tip of
his/her nose
Chair back
nearly parallel to
the floor
Patient’s Head
even with the upper
edge of the headrest.
headrest
the patient’s
head is in
chin up
position

50. Patient’s position for Mandibular Arch
Feet
even with or
slightly higher
than the tip of
his/her nose
Chair back
slightly raised at a 15-
20°angle to the floor
Patient’s Head
even with the upper
edge of the headrest
Headrest
Raised slightly
that the patient’s
head is in a chin
down position

51. DIRECT AND INDIRECT VISUALIZATION
In order to maintain a properly balanced, upright posture, it is important to
balance direct visualization with indirect visualization using the dental mirror.
 In order to widen the view without compromising good posture, the dentist
should ask the patient to place the head on the headrest and adjust it accordingly
to allow easier access, depending on which surface they are working.
HARMONIZING POSTURE AND VISION

52. MIRROR
A systematic mirror technique is necessary because practitioners tend to
assume unnatural and improper posture when trying to check difficult-to-see
and impossible-to-see regions.
LIGHTING
The light beam of the operating light must be perpendicular to the working
mandibular plane or to the working maxilla plane to be fully effective.
Dental handpieces with an integrated light source are ideal for illumination

53. PRINCIPLES OF MAGNIFYING LOUPES TO BE USED
AS INTERVENTION FOR MSDS
In terms of ergonomics it is allowing the
dentist to work in comfort zone with
proper posture, reducing the eye strain
and reducing the chair side time as well
Steps used in magnification are as follows:
Field of View
Depth of
Field
Declination
(viewing)
angle

54. With increase in magnification, the field of view
gets decreased.
Normally magnification of 2x–2.5x is used in
dental practice and also recommended for new
users.
Field of view
The depth of field refers to the
ability of the loupes to focus on both
near and far field of interest without
changing the position of the dentist.
Depth of view

55. Declination (Viewing) Angle
 The lesser the viewing angle, greater the need for the dentist to tilt
the neck and view the object.
 It is ergonomically important to make sure that this angle is correct
for the dentist in order to minimize strain on the neck, back and
shoulders.

56. ERGONOMICS BENEFITS OF LOUPES IN MSDS
Burton and Bridgeman in their study focused on the working distance
between the clinician and field of interest and implemented that by using
loupes the working distance can be kept at a comfortable constant position
securing up right posture of the dentist throughout the working life of the
dental practitioner
An Australian survey suggested that dental hygienists who wear loupes
are less likely to have any neck and shoulder, wrist/hand, or upper back
pain than those not wearing loupes.
Using magnifying loupes, the field of vision becomes so clear that
gripping of the instruments for longer period of time is avoidable

57. Plessas A (2018) systematic review where the role of
ergonomic saddle seats and magnification loupes in
preventing MSDs are analyzed in which four studies on
loupes as intervention are mentioned, improving the
quality of dental care professionals and dental students
in terms of working posture, pace of work that
ultimately results in accuracy of diagnosis and
detection.

58. MAGNIFICATION BY LOUPES AND MICROSCOPE
While using either loupes or a microscope, there should be an optimal
distance from the dentist’s eyes to the patient’s mouth to ensure clear
vision, good focus and ideal posture.

59. CHOICE OF INSTRUMENTS
EXAMINATION AND CONTROL INSTRUMENTS
Instruments with a large diameter (10 mm), textured
handle, and a light weight (15 grams) require the least
amount of muscle load and pinch force.
Consider alternating tools with different diameter sizes to
reduce the duration of prolonged pinch gripping.
 Silicone instrument handles
 A round handle, compared to a
hexagon handle will reduce
muscle force and compression.
 Favor gloves of proper size and
fit

60. FINGER RESTS
Instruments should be held in a light, pen-like grip, using a fulcrum (finger
rest) either intra-orally or extra-orally.
The use of 2-finger rests has shown musculoskeletal advantages when
performing scaling procedures.
When researchers examined three different finger positions (no rest, 1-
finger rest, and 2-finger rests) they found significant reductions in thumb
pinch forces and muscle activity when using rests.

61. EQUIPMENT LAYOUT
Dental equipment should be located in a manner which allows
you to maintain a neutral working posture.
 Frequently used items such as the syringe, hand piece, saliva
ejector and high volume evacuator should be positioned so they
are within a normal horizontal reach which is the arc created
while sweeping the forearm

62. AMBIDEXTERITY
The majority of people prefer the use of their
dominant hand when performing manual
operations.
It is recommended that individuals attempt to use
alternate hands throughout the workday, whenever
possible.
 Although this may not be practical for certain
precision tasks, it is possible to alternate hands
when performing accessory tasks, such as reaching
for tools or supplies.

63. ERGONOMICS IN DENTISTRY: ADVANCES AND
STRATEGIES
FOUR-HANDED DENTISTRY
 It is a method in which the dentist and
subordinate work together to execute
procedures that are designed with the
patient's best interests in mind.
 In a four-handed dentistry arrangement,
proper use of a dental auxiliary's extra pair of
hands is widely recognised as an optimum
manner of providing dental services.

64. The following requirements must be completed in order to practise proper
four-handed dentistry
1.
• All equipment must be developed with ergonomics in mind.
2.
• Surgical team and the patient must be seated in ergonomically
designed equipment.
3.
• the dentist should assign all legally delegable duties to
qualified auxiliaries based on the state’s guidelines.
4.
• Treatment for the patient should be planned ahead of time and
arranged in a logical manner.
5.
• Preset trays should be utilized

65. Zones of activity:
The work area surrounding the patient is divided into 4 "activity-zones“
To detect activity zones, the patient's face is utilised to simulate the face of a
clock.
The four activity zones are
Operator’s zone
Assistant’s zone
Static zone
Transfer zone

67. STRATEGIES TO ENSURE EFFECTIVE FOUR HANDED
DENTISTRY
TEAMWORK
To effectively implement the concepts of true four handed dentistry
each member of the dental team must assume individual as well as
team responsibilities.
The team must be aware of each other’s needs, recognize the needs
to reposition the patient and operating team.

68. STRATEGIES FOR THE OPERATOR
The dentist/ Operator should develop standardized routine for basic dental
procedures
Develop a non verbal signal denoting a need to exchange an instrument.
When necessary give advance distinct verbal direction to communicate a need
for a different instrument or material.
The dentist/ operator must be willing to accept input from the assistant when it
is noted that chair positions need to be adjusted.
Avoid twisting and turning to reach instruments

69. When in practice the dental assistant should
change burs in the handpiece and maintain a ready
position for delivery of the handpiece
Remove debris from the instruments before
returning them to the preset tray.
Maintain a clean work area at all times.
Communication between the operator and the
assistant is vital to successfully implement the
concepts of four handed Dentistry

70. STRATEGIES FOR THE ASSISTANT
Develop a thorough understanding of the procedure.
Recognize the patient’s needs.
Anticipate the operator’s needs and recognize any change in the
procedure.
Be seated as close to the patient as possible with legs parallel to the long
axis of the patient’s body.

71. All these principles allow the practisioner to work smarter and not
harder.
When practiced properly, four-handed dentistry results in less
fatigue, less burnout, fewer physical challenges, greater
productivity, and greater job satisfaction for both dentists and
assistants.
Patients also appreciate receiving the undivided attention of a
well-coordinated dental team and have a much more comfortable
clinical experience when treated by a team, rather than by an
individual.

72. STRETCHING
Frequent stretch breaks can prevent detrimental physiological changes
that can develop while working in static or awkward postures.
 In an attempt to prevent injury from occurring to muscles and other
tissues, dental professionals should allow for rest periods to replenish and
nourish stressed structures.
If breaks are too far apart, the rate of damage could exceed the rate of
repair and eventually lead to the breakdown of tissue.

73. Researchers suggest that dental professionals try to lean back on their
stool at least four times during each treatment session as well as spend
three to five minutes stretching for every patient seen throughout the
day

74. Also, Take a break from activities and focus eyes at a distance for
20 seconds to relieve eyestrain caused by focusing hard on one
depth of vision for extended periods of time.
If there is neck stiffness, rotate your head in a comfortable range of
motion from forward and backward, right and left.
Shoulder rolling can help stretch fatigued shoulder muscles from
holding an oral evacuator, tools,

75. CONCLUSION
High productivity, injury prevention, and greater patient
satisfaction are all benefits of successful ergonomics in the
dental operatory.
 MSDs can be avoided by following some fundamental
principles and maintaining a healthy posture.
Regular continuing dental education seminars and lectures
should be promoted to raise awareness among dental
practitioners.
 Four-handed dentistry should be used on a regular basis to
promote efficiency and convenience.

76. REFERENCES
ERGONOMICS AND POSTURE GUIDELINES FOR ORAL
HEALTH PROFESSIONALS Content developed by Health and Safety
Task Team (T. Caruso, D. Ilhan, M. Ishida, J.M. Laffont) ©2021 FDI
World Dental Federation.
Gupta A, Bhat M, Mohammed T, Bansal N, Gupta G. Ergonomics in
dentistry. Int J Clin Pediatr Dent. 2014 Jan;7(1):30-4. doi: 10.5005/jp-
journals-10005-1229. Epub 2014 Apr 26. PMID: 25206234; PMCID:
PMC4144062.
Dushyant Datkar, Akash Sibal, Bhairavi Kale, Ergonomics in Dentistry:
A Review, J Res Med Dent Sci, 2022, 10 (7): 087-091.
Sachdeva A, Bhateja S, Arora G. Ergonomics in dentistry: A
comprehensive review. J Dent Res 2020;7:32-5.

77. Harpreet Kaur ,Vandana A. Pant ,Vandana Gupta “Magnification in
Dental Ergonomics – A Comprehensive Review” Advances in
Bioscience and Clinical Medicine Volume: 10 Issue: 1 January 31,
2022.
ERGONOMICS IN DENTAL PRACTICE Shah A.F. et al., Int J Dent Health
Sci 2014; 1(1): 68-78.
Rajvanshi, et al.: A Review on Ergonomics in Dentistry: International
Journal of Scientific Study | September 2015 | Vol 3 | Issue 6
Shipra Gupta. Ergonomic applications to dental practice. Indian
Journal of Dental Research,22(6),2011

78. THANKYOU