Chair Positions Class 1f6h3w

CHAIR POSITIONS - 4 HANDED DENTISTRY INSTRUMENT GRASPS AND FINGER RESTS

 The concept of four-handed dentistry

described by Dr. G.E.Robinson  Research shows that production can be increased by 100% and simultaneously stress and fatigue will be reduced by 50% -70%.

The Benefits Include:  Increased efficiency  Decrease in the muscular

stresses involved with the practice of dentistry through conservation of muscular activity, adherence to the principles of balanced posture.  The dentist is able to concentrate their skill and judgment on the tasks directly associated with patient care.

Team Dentistry  Goals of work simplification  Decrease the number of instruments to be used for a      

procedure. Sequence the instruments on a tray by their use. Minimize the stress and fatigue by using correct positioning of the patient, dentist and assistant. Use of appropriate moisture control techniques. Transfer of instruments and dental materials as necessary. Use the least amount of motion during the transfer of instruments and materials. Allow the assistant to perform expanded functions.

POSITIONING THE PATIENT AND THE OPERATIVE TEAM

Objectives of a Favorable Seated Position  Access to the operative field  Good visibility  Comfort for the operative team- reduced

stress and increased efficiency  Relative comfort and safety for the patient

Position should permit direct or indirect vision

ZONES OF ACTIVITY •Patient in a supine position •Using center of patients face as a clock •Zones designated as time

Positioning the Operator  Work environment is adapted to the operator  Operator positioned first then  Patient  Assistant  equipment

•The dentist will normally work within a range from the 12 o’clock to the 7 o’clock position relative to the patient’s head. • However, most operative procedures are completed from, at, or near, the 12 o’clock position. •The dental nurse will normally remain in a fixed position at 4 o’clock .

 Maxillary incisor labial surface – 7 o’ clock  Maxillary incisors lingual surface – 12’ o clock  Maxillary posteriors – 12’ o clock  Mandibular incisors labial surface- 7’ o clock  Mandibular posteriors – 9’ o clock and 7’ o clock

Characteristics of Balance Posture for Operator  Operators thighs parallel 

 

 

to floor Entire surface of seat used to weight Backrest s back without interference Forearms parallel to floor when hands are in operative position Elbows close to the body Back and neck reasonably upright with top of shoulders parallel to floor

 Distance of approximately 14 – 18 inches between

the operator’s nose and the patients oral cavity maintained  Operative field is operators midline

× 

Positioning the Patient in the Working Position  Oral Cavity at height of operator’s elbow  Head placed at upper end of chair and slightly

to operators side of chair  All patients are seated from the head down

Steps to position a Patient  Adjust back approximately 60 degrees to vertical  Raise chair to height patient can easily be

seated  Raise arm of chair  Once patient is seated  Armrest down  Raise chair approximately 10 inches to allow Dr. to

position himself

 Tilt seat portion back so foot rest is raised approximately 6 to 8 inches  Lower back of the chair until patient is about

½ way toward a horizontal position  Pause to allow patient to adjust

 Continue lower chair back until following

relationships exist  Imaginary line from patients chin to the top of

ankles is parallel with floor

Once seated – Observe Patient  Lying flat with little bending at waist  Similar to sleep position  Legs slightly lower than head – if higher

might cause – pt. Anxiety/circulation problems.  Patient in supine position

 Lower chair to operators lap  Approximately 1 inch above knees of operator  Plane of the patients forehead is also parallel with

the floor

Supine Position  Universal position for all working positions  Patient is lying down facing upwards  Slight modifications only allowed as patients

needs are assessed

Patient Dismissal  Patient dismissal should be accomplished by reversing the steps of seating the patient  to pause for the patient on the

way up as well  Most important patient dismissal precaution  Encourage the patient to remain seated to

reestablish their equilibrium

Positioning the Assistant The dental nurse will normally remain in a fixed position at 4 o’clock but at a considerably higher position in order to look down or forward to the mouth.

 Must be able to visualize back of the

mouth and have favorable access to be able to  Retract tissues  Evacuate fluids  View to anticipate needs of operator  Maintain clear field

Position of Assistant  3 – 4 o’clock position for all quadrants  Right handed operator

 9 o’clock position for all quadrants  Left handed operator

 Stool positioned so edge toward the top of patients head is in line with the patients oral cavity  Stool as close to chair as possible

 Stool elevated to top of assistants head is 4 – 6 inches higher than the dentist

Standardization of Work Procedures and use of transfer zone  Contributes to effective teamwork by being able to

anticipate the dentist’s needs & increasing efficiency/production

Examples of Standardization for Work Simplification  Arrange steps into smooth sequence  Use preset trays in order of use from left to

right  More than one operatory.  Each treatment room identical in equipment  And materials

Instrument Transfer and Exchange  Benefits  Standardized operating sequence.  Reduces the amount of time in the dental chair for

the patient.  Increased productivity.  Less fatigue and stress.

Instrument Transfer and Exchange- cont’d  Principles of instrument transfer  The assistant must understand the sequence of the



 

 

treatment procedure and anticipate when an instrument transfer will be required. The transfer of instruments should be accomplished with a minimum of motion involving only the fingers, wrist, and elbow. Instruments are transferred in the position of use. An instrument is transferred so the dentist can grasp the instrument for its appropriate use. The instrument being transferred must be positioned in the dentist's hand firmly. The assistant will transfer dental instruments and dental materials with his or her left hand.

Instrument Transfer and Exchange- cont’d  Variations in instrument transfer    

Mirror and explorer Cotton pliers Handpiece Instruments with hinges

Sit Down Dentistry  Body mechanics/task performance studies  Seated worker uses 27% less energy  Seated worker has 17% greater life expectancy

 Production increases from 33 – 78%

 Seated in a balance posture concept  ½ the efficiency of a D.A. Is the result of

working with a well-organized dentist who practices 4-handed dentistry

Instrument Grasps

Pen Grasp

 With the pen grasp  hold the instrument the way

you would hold a pen when writing. Grasp the handle with your thumb and first while your middle finger s the instrument from beneath.

Modified pen Grasp 

 

With the modified pen grasp, hold the instrument in basically the same way as in the pen grasp, except that the fleshy part of your middle finger rests lightly on the shank of the instrument (fig). This finger is used to feel the shank vibrate when the instrument's working end rubs over a rough surface. The middle also helps to guide the instrum ent. The ringfinger is used to stabilize the hand in the patient's mouth. Balance your hand and the instrume ntation with this finger

Inverted Pen Grasp Inverted Pen Grasp. The finger positions of the inverted pen grasp are the same as for the modified pen grasp. However, the hand is rotated so that the palm faces more toward the operator (Fig). This grasp is used mostly for tooth preparations utilizing the lingual approach on anterior teeth.

Palm and thumb grasp  PALM GRASP

When using the palm grasp, the index, middle, ring, and little finger hold the instrument so that it rests in the palm of your hand. Your thumb remains free to stabilize your hand in the patient's mouth, or it may be used to an instrum ent when sharpening (fig). This grasp is rarely used in the mouth and only when exceptional force is needed.

Modified Palm-and-Thumb Grasp  The modified palm-and-thumb

grasp may be used when it is feasible to rest the thumb on the tooth being prepared or the adjacent tooth (Fig.).  The handle of the instrument is held by all four fingers whose pads press the handle against the distal area of the palm, as well as the pad and first t of the thumb.  Grasping the handle under the first t of the ring and little fingers acts as a stabilizer.  This grip fosters control against slippage.

Finger grip  The instruments are grasped using the fingers and the thumb

is used to guide the instrument .

Finger Rests

Finger rests  The 4th finger ( ring finger ) is used to stabilize the hand and

reduce the likelihood of uncontrolled movement & injury  The finger rest also acts as a fulcrum for working movements  Finger rests maybe  In the same arch on tooth surfaces in the immediate vicinity of the

working area  They maybe cross arch ( on tooth surfaces on the opposite side in the same arch)  Opposite arch  Extra oral

 The closer the rest areas are to the operating area, the more reliable they are

Finger rests – Intra oral

Intra arch

No rest

Single finger

Two finger rest

Inter arch

Extra oral

 Under these circumstances, instrument control may be gained using the forefinger of the opposite hand on the shank of the instrument or using an indirect rest, (i.e., the operating hand rests on the opposite hand, which rests on a stable oral structure)

Conclusion Advantages of 4 handed dentistry  Better ergonomics  Better efficiency  Lesser stress on operatory team and patient Ergonomics is the science of deg the job, equipment, and workplace to fit the worker. Proper ergonomic design is necessary to prevent repetitive strain injuries, which can develop over time and can lead to long-term disability.