Ergonomics can roughly be defined as the study of people in their working environment. scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles and methods to design to optimize overall human performance.” Improves job process by eliminating unnecessary tasks,steps and efforts. Reduce potential for overexertion injury. Minimize mental/physical fatigue potential. Leverage workers’ skills & knowledge .The objective is to improve the efficiency of operation by taking into account a typical person’s size, strength, speed, visual activity and physiological stresses such as fatigue, speed of decision making, and demands on memory and perception. To maximize productivity while lowering the risk of musculoskeletal disorders(MSDs).MSDs develop as a result of long term exposure to a combination of ergonomic risk factors such as repetition, high forces and awkward postures.

1. ERGONOMICS
Presented by : Farsana T N
3rd year, Annoor Dental College

2. CONTENTS
 Definition
 History
 Goals
 Types
 Ergonomics in dentistry
 Risk factors
 Application in dentistry
 Wrong postures and prevention
 Four handed dentistry
 Work simplification techniques
 Scope in dentistry
 Conclusion
 Bibliography

3. WHAT IS ERGONOMICS?
• ISO 6385 defines "ergonomics" as the "scientific discipline concerned
with the understanding of interactions among humans and other
elements of a system, and the profession that applies theory,
principles and methods to design to optimize overall human
performance.”
• The word ergonomics —“the science of work” — is derived from the
Greek ergon (work) and nomos (laws).

4. • In simple words, it is the study of people's efficiency in their working
environment.
• Ergonomics can roughly be defined as the study of people in their
working environment.
• More specifically, an ergonomist designs or modifies the work to fit
the worker, not the other way around.
• Ergonomists study human capabilities in relation to work demand.

5. HISTORY
• As early as 18th century, doctors noted that workers who required to
maintain body positions for long periods of time developed musculoskeletal
problems.
• Since the beginning of time, we have been trying to make everything more
efficient with less stress.
• The idea of ergonomics became much more popular during the industrial
revolution.
• Work related injuries are dated back to the 16th century. For example, early
man used tools like sharpened tools to make tasks easier rather than using
blunt ones.
• During WW1, plane cockpits were so ergonomically inefficient, causing
accidents. This also had a huge push for ergonomic advancements today.

6. FATHER OF ERGONOMICS
• Alphonse Chapanis is considered as
the ‘Father of Ergonomics’.
• Wojcieh Jaztrzebwoski coined the
term ergonomics in a philosophical
narrative , “based upon the truth
drawn from the science of nature.”

7. GOALS OF ERGONOMICS
• Improves job process by eliminating unnecessary tasks,steps and efforts.
• Reduce potential for overexertion injury.
• Minimize mental/physical fatigue potential.
• Leverage workers’ skills & knowledge of their jobs to increase their
satisfaction,comfort & fulfilment.

8. • The objective is to improve the efficiency of operation by taking into
account a typical person’s size, strength, speed, visual activity and
physiological stresses such as fatigue, speed of decision making, and
demands on memory and perception.
• To maximize productivity while lowering the risk of musculoskeletal
disorders(MSDs).MSDs develop as a result of long term exposure to a
combination of ergonomic risk factors such as repetition, high forces
and awkward postures.
• Examples of MSDs include carpel tunnel syndrome, tendonitis and
back disorders.

9. TYPES
3 types:
1. PHYSICAL
2. COGNITIVE
3. ORGANIZATIONAL

10. 1.PHYSICAL ERGONOMICS
• Also known as occupational ergonomics.
• It is concerned with the interaction of the body with the equipment
and the tools, starting right from the chair to the computer.
• Repetitive strain injuries from repetition, vibration , force and posture
are the most common types of issues and thus have design
implications.
• examples of physical ergonomics include:
 Using an adjustable ergonomic chair
Using wrist support and footrests.

12. 2. COGNITIVE ERGONOMICS
• Cognitive ergonomics deals with mental processes such as perception,
memory, thinking, and mobility and the way they are affected by the
interaction with the remains of the observed system.
• The most important aspects include mental effort ,decision making,
interaction with computers, human reliability and work stress.
Examples of cognitive ergonomics
include:
Designing a software interface to be
“easy to use”.
Deciding the position of
patient,lighting,the instruments
required and all the necessary
precautions to be undertaken.

13. 3.ORGANIZATIONAL ERGONOMICS
• Also known as macro-ergonomics.
• It mainly considers the structures, policies and processes of any
organization.
• The goal of organizational ergonomics is to achieve a harmonious
system, taking into consideration the consequences of technology on
human relationships, processes and organizations.
• It works on complete optimization of the workplace, right from quality
management to teamwork, i.e,managing everything in organization to
make it a better place to work.

14. Relevant topics of organizational ergonomics:
Shift work
Scheduling
Job satisfaction
Supervision
Teamwork
Ethics

15. • When evaluating a job, looking for three main characteristics known as
Ergonomic Stressors:
 the force required to complete a task,
 any awkward or static working postures adopted in completing a task,
 the repetitiveness of a task.
Any of these factors, or any combination of these factors, may place someone at
greater risk for discomfort

16. IS ERGONOMICS ESSENTIAL
IN DENTISTRY ???

17. WHY SHOULD WE CARE?
• More than 70% of dental students of both sexes reported neck,
shoulder and lower back pain by their 3rd year of dental school.(2019).
• Also seen in 81% of dental operators.(2019)
• The common reason for early retirement in dentists is MSDs.

18. Risk factors
contributing
to MSDs
Prolonged use of
vibrating hand tools
Repetitive motions
(ex: scaling, polishing)
Excessive force
(ex: tooth extraction)
Static neck, back and
shoulder postures
Grasping small
instruments for
prolonged periods

20. APPLICATIONS OF ERGONOMICS IN
DENTISTRY
A) INSTRUMENTS:
Hand instruments
vibrating handpieces
B) Equipments
Lighting magnification
Operator and patient chair
C) Work postures
Patient position
Dentist position

21. INSTRUMENTS
1)Hand instruments:
• Goal: To reduce force exertion while allowing for neutral joint
positioning.
• Design :
Dental instrument diameter ranges from 5.6-11.5 mm.
Larger diameter handles reduce hand muscle load and pinch force.
Sleeves that fit over the handles of mirrors.
Round handle vs hexagonal handle.

22. • Weight:
Light weight instruments(15g or less)
Hollow vs resin
• Balance:
Should be equally balanced within the hand so that the tendency to
deviate the wrist is reduced.
• Sharpness and texture:
As a tool becomes dull, additional force is required to perform tasks.

24. 2) Dental hand pieces:
When selecting handpieces, look for the following:
a. light weight, balanced models (cordless preferred).
b. sufficient power
c. built-in light sources
d. angled vs. straight shank.
e. easy activation

26. 2. EQUIPMENTS
• Dental equipments should be located in a manner which allows you to
maintain a neutral working posture and reduce postural deviation while
working.
A) Lighting:
* Goal: To produce even, shadow free, colour corrected illumination
concentrated on the operating field to avoid strenuous working postures.
* Overhead light should be positioned as close as possible to the sight
line.
* Hand mirrors to reflect light intraorally.
* Use fibre optics in handpiece.

28. B) Magnification :
* Goal: To improve the neck posture and provide clear vision.
* Use of various magnification systems,dental professionals are able to
increase their working distance and assume more of an upright body
posture.
* ‘SURGICAL LOUPES’ can be mounted to a headband or onto the
operator’s glasses.

30. C) PATIENT’S CHAIR:
* Goal: To promote patient comfort and maximum patient access.
* Look for :
-Stability
-Pivoting or drop down arm rests(for patient ingress/egress).
-Supplemental wrist (for operator).
-Articulating head rests.
-Hands free or present operation.

32. D) OPERATOR CHAIR:
Goal: To promote mobility and patient
access and to accommodate different body
sizes.
Look for:
- Stability(5 legged base)
-Adjustable lumbar support.
-Seat height adjustments.
-Adjustable foot rests.
-Adjustable wrap around body support
or arm support.

33. • RGP’s new straddle stool:
Provides optimal seating allowing for proper positioning of the spine and
pelvis.
The straddle stool pre-positions into an anterior pelvic tilt.
The angle of the 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.

35. 3. POSTURES
A) Operator position:
Neutral positioning is the ideal posture of the body while performing
work activities and is associated with decreased risk of MSDs.

36. Neutral seated position in relation to the
patient:
1. Forearms parallel to the floor.
2. Weight evenly balanced.
3. Thighs parallel to floor and knees are apart.
4. Hip angle of 90˚.
5. Seat height positioned low enough.
6. Shoulders relaxed and parallel with floor.
7. Eyes directed downwards.
8. 14-16 inches distance should be between
patient’s mouth and clinician’s eyes.
9. Elbows close to sides.
10. Patient’s mouth at elbow height.

38. B.PATIENT POSITION
• Supine position.
• The chair back should be nearly parallel to the floor for maxillary treatment areas
(chin up).
• The chair back may be slightly raised for mandibular treatment areas(chin down).

39. WRONG POSTURES IN DENTAL OFFICE
Leaning Bending of neck & arching of back
Elevation of shoulders

40. HOW TO AVOID ALL THIS PAIN?

41. THE GOLDEN TIP !
• First step is to break down everything you need
into different categories: Restorative, Crown &
Bridge, Oral Surgery, Lab supplies, Endo, etc.
• Position your chair close to your patient, and
position your instrument tray close to you.
This way, you don’t have to overextend
yourself to reach your patient or your
instruments, putting excessive stress on your
back, shoulders, and arms. Think of the 90°
rule of having your elbows, hips, knees, and
ankles all forming 90° angles.

42. SCHEDULING
Recommendations when scheduling include:
• Incorporate brief “stretch break” periods between patients.
• Develop a patient difficulty rating scale to ensure difficult treatment
sessions are not performed consecutively.
• Increase treatment time for more difficult patients.
• Alternate light and heavy calculus patients throughout the day.
• Alternate procedures performed.

43. STRETCHING EXERCISES TO KEEP DENTAL TEAM
FIT

45. ERGONOMIC STRETCHES
Stretching should never be painful.
If you notice pain, STOP!!!

46. FOUR HANDED DENTISTRY

47. FOUR HANDED DENTISTRY
• “It is an ergonomically sound way to practice dentistry using the skills of
dental assistant while including work simplification procedures.
• The term ‘Four handed dentistry’ was recorded in a conference on
‘training dental students to use chair side assistants’ in 1960. Now this
term is widely used.
• GOAL: To allow the dentist and assistant to function as a team in a
seated position with maximal efficiency and minimal strain.

48. To practice four handed dentistry, the following criteria must be met:
• Minimize unnecessary motions, equipments must be ergonomically designed.
• Both the operating team and the patient should be comfortably seated.
• Pre-set trays are utilized.
• The dentist assigns all legally delegable duties to qualified auxiliaries based on the
state’s guidelines.
• Treatment plan of the patient is designed in advance in a logical sequence.

49. ZONES OF ACTIVITY
The work area around the patient is divided into 4 zones of activity. These zones are
identified using the patient’s face as the face of a clock.
a) Operator’s zone
b) Assistant’s zone
c) Transfer zone
d) Static zone

51. EQUIPMENT SET UP DESIGN
The basic dental unit designs available today include:
• Side delivery
• Rear delivery
• Split unit
• Transthorax

53. WORK SIMPLIFICATION TECHNIQUES
• These techniques are applied in a dental office for making work easier, safer, more
effective and to make the work environment more comfortable.
• 4 principles of work simplification:
a. Elimination
b. Combination
c. Rearrangement
d. Simplification

54. 1. ELIMINATION:
• 100% saving can be accomplished by the elimination of unnecessary equipment,
instruments, steps in procedures and movements.
2. COMBINATION:
• If the functions performed by two instruments or pieces of equipment can be
combined into one instrument or pieces of equipment can be combined into one
instrument or a piece of equipment,or if two steps in a procedure can be combined
and accomplished in one step, 50% saving can be realized.

55. 3. REARRANGEMENT:
• It may be possible to rearrange equipment and materials in the operatory ,
scheduling of patients, or steps in clinical procedures to take better advantage of
available space and time.
4. SIMPLIFICATION:
• Every effort should be made to simplify dental equipment & patient treatment
procedures inorder to introduce a minimum number of variables and permit the
team to function most efficiently.

56. CONCLUSION
• Considering the impact of ergonomically designed and chosen equipment on
efficiency, one must modify the workplace to reduce the possibility of injuries.
• Among the various occupational hazards, MSDs are very much at the disposal of
the clinician himself.
• Adopting new techniques, armamentarium and work strategies can definitely
prevent detrimental changes in the future.
• The job of a dentist is not an easy one; it comes with a challenging workload,
little time and, often, emotional patients, so why make things any harder? An
ergonomic dental clinic design will result in happier and healthier staff, as well
as greater productivity and more satisfied patients. In short, it’s an investment
well worth making.

57. BIBLIOGRAPHY
• https://www.slideshare.net/docrakesh/ergonomics-in-dentistry :(Dr.Rakesh Nair, 2015)
• Ergonomics in dentistry-review; Research gate (Sachdeva A, Bhateja S, Arora G.
Ergonomics in dentistry: A comprehensive review. J Dent Res Rev 2020;7:32-)
• Ergonomic design for dental practice(aspd,2019)
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4144062
• Ergonomics in dentistry- Research gate
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC414406
• Ergonomics in dentistry- oral journal
• Ergonomics- wikipedia