This document discusses dental ergonomics and the proper positioning of dental chairs, patients, and operators. It notes that the first specialized dental chair was invented in 1790 using a modified Windsor chair. Modern dental chairs are designed to support the patient's body in any position and reduce strain on the neck. For procedures, patients may be seated in an almost supine or 45-degree reclined position. Proper operator positioning is also important for visibility, accessibility, and to avoid musculoskeletal disorders, with forearms parallel to the floor and other guidelines provided.

2. • HISTORY
• INTRODUCTION
• DENTAL CHAIR AND PATIENT POSTIONS
• OPERATOR POSITIONS
• OPERATING STOOLS
• GENERAL CONSIDERATIONS

3. • 1790 was a big year for
dentistry, as this was also
the year the first
specialized dental chair
was invented.
• It was made from a
wooden Windsor Chair
with a headrest attached.

4. INTRODUCTION
 Until a few decades ago , most
dental procedures were performed
with patient seated upright and
dentist standing next to patient
,this prolonged period caused
musculoskeletal disorders for
dentists.
 The role of Ergonomics in dentistry
can avoid these occupational
hazards .

5.  Proper positioning of the patient and
operator, illumination and retraction for
optimal visibility are fundamental pre
requisites to proper dental treatment

6.  Modern dental chairs are
designed to provide to
provide total body support in
any chair position.
 The patient head is
supported by a head rest
cushion which elevates the
chin and thus reducing strain
on neck
Dental chair and patient position

7. For operative dental procedures , the patient
may be seated in one of the following
positions:
1. Almost supine
2. Reclined 45 degrees

8. 1. ALMOST SUPINE POSITION:
 In this position the chair is tilted so that the
patient is almost in a lying down posture
 The patient’s head ,knees and feet are
approximately at the same level
 The head should not be positioned below the
feet level as blood pressure increases
gradually

9. 2. RECLINED 45 DEGREE POSITION:
 In this position the chair is reclined at 45 degrees
so that when the patient is seated, the mandibular
occlusal surfaces are almost at 45 degrees to the
floor
 Once the treatment is over the chair is brought
back to upright position so that the patient can
leave the chair easily

10. POSITONS OF THE OPERATOR
 Forearm parallel to the floor
 Thighs parallel to the floor
 Hip angle of 90 degrees
 Seat height positioned low enough
so that the heels of your feet touch
the floor

11.  When working from clock
positions 9-12:00, feet spread apart
so that your legs and the chair base
form a tripod which creates a
stable position
 Avoid positioning your legs behind
the patient’s chair
 Back of the operator should be
always straight
 Head erect and should not be bent
of drooping

12. Operator position:
The main thing which we have to
consider are the Operator Position
Correct positioning of the operator is
very important to operator to have
good visibility and accessibility to
oral cavity.

13.  FOR A RIGHT HANDED OPERATOR:
1. Right front or 7’o clock position
2. Right or 9’o clock position
3. Right rear or 11’o clock position
4. Direct rear or 12’oclock position

14. RIGHT FRONT POSITION:
 This is convenient for examination and working on
the mandibular anterior teeth ,mandibular right
posterior teeth and maxillary anterior teeth

15. RIGHT POSITION :
 The operator is directly to the right
of the patients.
 The position is convenient for
operating on the facial surface of the
maxillary & mandibular right
posterior teeth & occlusal surface on
mandibular right posterior teeth .
 Pen grasp is used for this position.

16. RIGHT REAR POSITION:
 From this position the dentist can have
good access to most areas of the mouth
using direct or indirect vision. The
dentist sits to the right and slightly
behind the patient and the left arm is
positioned around the patient’s head
 In this position working on the lingual
surfaces of maxillary anterior teeth is
most convenient.

17. 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
for working on lingual surfaces of
mandibular anterior teeth , lingual
surfaces of maxillary anterior teeth.

18. Operator stools:
 The design of the stool is important.
 It should be sturdy and well balanced to
prevent tipping/gliding away from dental
chair
 It should be well padded with cushion
edges and should be adjusted up and down
 A well designed stool increases operator
comfort and reduces fatigue

19. LIGHTING;
 The operator should be well illuminated
either by natural or artificial light.
 If the light is kept too close , it impairs the
physical movement of operator & also
increases patient discomfort due to heat
production.
 If the light is kept far away, it reduces the
illumination.
 As a rule for mandibular arch the light is
kept in a higher position & for maxillary
arch it is kept in a lower position.

20. general considerations:
 The patient’s head should be rotated according to need of operator
without hesitation
 During working maxillary occlusal surfaces should be perpendicular to
the floor and for mandibular occlusal surface should be 45 degrees
 The operator should maintain space between the patient as while
reading a book
 There should be reduced contact with that of patient
a) The operator should never rest his hand on patient’s face
b) The chest of patient should never be used as trays to keep instruments
 The left hand should be kept free to retract using the mouth mirror

22. REFERENCES:
 Sturdevent’s Art & Science of operative Dentistry.
 Clinical Operative dentistry- Ramya Raghu &
Raghu Srinivasan
 Internet sources

23. PRESENTED BY :
J MITHUN KASHYAP
VARSHA MALVADKAR
YAMUNA
DEEBA SADAF
VASUDHA
VEENA
ZAHIRA