Principles of Position :

Principles of Position

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1 - NEUTRAL POSITION FOR THE CLINICIAN
Research indicates that over 80 percent of denial hygienists complain of pain in the upper body and hack.1 This musculoskeletal pain often is the direct result of body positioning and movements made by dental hygienists in their daily work. Neutral position is the ideal positioning of the body while performing work activities and is associated with decreased risk of musculoskeletal injury (fig-1). It is generally believed that the more a joint deviates from the neutral position, the greater the risk of injury.


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1.
Forearms parallel to the floor
2. Weight evenly balanced
3. Thighs parallel to the floor
4- Hip angle of 90°
5. Seat height positioned tow enough so that you are able to rest the heels of your feet on the floor
Box -1. Neutral Seated Position





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Neutral Neck Position
COAL:
• Head tilt of 0° to 15°
• The line from eyes 10 the treatment area vertical as possible
AVOID:
• Head tipped too far forward
 • Head tilted to one side





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Neutral Back Position
GOAL:
• Leaning forward slightly from the waist or hips
• Trunk flexion of 0° to 20°
AVOID:
• Overflexion of the spine (curved back)





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Neutral Shoulder Position
COAL:
• Shoulders in horizontal line
• Weight evenly balanced when seated
AVOID:
• Shoulders lifted up toward cars
• Shoulders hunched forward
• Sitting with weight on one hip






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Neutral Upper Arm Position
COAL:
• Upper arms hang parallel to the long axis of torso
• Elbows at waist level held slightly away from body
AVOID:
• Greater than 20° of elbow abduaion away from the body
• Elbows held above waist level






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Neutral Forearm Position
COAL:
• Parallel to the floor
• Raised or lowered, if necessary, by pivoting at the el­bow joint
AVOID:
• Angle between forearm and upper arm of less than 60°






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Neutral Hand Position
COAL:
• Little finger-side of palm slightly lower than thumb-side nf palm
• Wrist aligned with forearm
AVOID:
• Thumb-side of palm rotated down so that palm is parallel to the floor
• Hand and wrist bent up or down
2-  





Patient Position
SUPINE PATIENT POSITION
Supine position—the position of the patient during dental treatment, with the patient lying on his or her back in a horizontal position and the chair bock nearly parallel to the floor (Table -1 ).
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TABLE 1. The Supine Patient Position
Recommended Position
Body The patient's heels should be slightly higher than the tip of the nose. This position mam-tains good blood Dow to the head. An apprehensive patient is more likely to faint if posi­tioned with the head higher than the heels.
The chair back should be nearly parallel to the floor for maxillary treatment areas. The chair back may be raised slightly for mandibular treatment areas.
Head The top of the patient's head should be even with the upper edge of the headrest. If nec­essary, ask the patient to slide up in the chair to assume this position.
Head nest If ihe headrest is adjustable, raise or lower it so that the patient's neck and head are aligned with the torso.




PATIENT HEAD POSITION
The patient's head position is an important factor in determining whether the clinician can see and access rhc teeth in a treatment area. Unfortunately, a clinician may ignore this important aspect of patient positioning, contorting his or her body into an uncomfortable position instead of asking the patient to change head positions. Working in this manner not only causes stress on the clinician's musculoskeletal system but also makes it difficult to sec the treatment area. Remember that the pa­tient is only in the chair for a limited period of time while the clinician spends hours at chairside day after day. The patient should be asked to adjust his or her head position to provide the clinician with the best view of the treatment area (Table 2).




TABLE 2. Basic Positioning of the Patient's Head
Recommended Position
Position on Headrest To be able to see and reach the patient's mouth comfortably, the top of the patient's head must be even with the end of the headrest.
Mandibular Areas Ask your patient to open the mouth and tilt the head downward. The term for this patient head position is the chin-down position.
Maxillary Areas Ask your patient to open the mouth and position the head in a neutral po­sition. The term for this patient head position is the chin-up position
Clinician and Equipment Position
THE ADJUSTABLE CLINICIAN CHAIR
Ergonomics is the science of adjusting the design of tools, equipment, tasks, and environments for safe, comfortable, and effective human use. Blood circulation to your legs, thighs, and feet is main­tained by adjusting the clinician chair to a proper height. Minimize stress on your spine by moving the chair back closer to or farther away from the scat so that your upper arms and torso are aligned with the long axis of your body.
Each clinician who uses the chair should readjust it to fit his or her own body. A chair that is adjusted correctly for another person may be uncomfortable for you. Just as each driver of the fam­ily car must change the position of the driver's seat and mirrors, you should adjust the clinician chair height and seat back to conform to your own body proportions and height.
The chair should have the following design characteristics
1. Legs—five legs for stability; casters for easy movement
2. Height
• Should allow clinician to sit with thighs parallel to the floor. A scat height range of 14 to 20 inches accommodates both tall and short clinicians.
• Should be easily adjustable from a seated position.
3. Seat
• Front edge of seat should have a waterfall shape (rounded front edge).
• Should not be too heavily padded; thick padding requires constant minor readjustments to maintain balance.
• When seated with the back against the backrest, the seat length should not impinge on the back of the clinician's knees. A seat length of 15 to 16 inches fits most clinicians.
4. Backrest
• Should be adjustable in both vertical and horizontal directions so that it can be positioned to touch the lumbar region of the back when comfortably seated.
• Angle between the seat and the chair back should be between 85 and 100 degrees.
PATIENT POSITION RELATIVE TO THE CLINICIAN
The first component in avoiding fatigue and injury is proper positioning of the patient in relation to the seated clinician (fig 2 and 3). While working, the clinician must be able to gain access to the patient's mouth and the dental unit without bending, stretching, or holding his or her elbows above waist level.




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1. First, adjust the height of the clinician chair to estab­lish a hip angle of 90°.
2. Next, lower the patient chair until the tip of the pa­tient's nose is below the clinicians waist level, your elbow angle should be at 90 when your fingers are touching the teeth in the treatment area.
3. AVOID placing your legs under the back of the pa­tient chair—in this position the patient will be too high and you will need to raise your arms to reach the patient's mouth. It is acceptable to place your legs under the headrest of the chair.
Box 2. Establishing Neutral Position in Relation to the Patient








Common Positioning Error
The most common positioning error made by clinicians during periodontal instrumentation is posi­tioning the patient too high in relation to the clinician.

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Incorrect Positioning—Patient Too High. Note how this clinician must hold her elbows up in a stressful position to reach the patient's mouth.
This error is often the result of a misconception that the clinician can see better if the patient is closer. Actually, the reverse is true; the clinician has improved vision of the mouth when the patient is in a lower position.









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PROPER POSITION FOR THE PATIENT
1. Sit alongside the patient with your arms against your sides and crossed at your waist The patient's open mouth should be below the point of your elbow.
2. With the patient in this position, you will be able to reach the mouth without placing stress on the muscles of your shoulders or arms.
 Box 3. Easy Technique for Establishing Neutral Position in Relation to the Patient







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EQUIPMENT POSITION RELATIVE TO THE CLINICIAN
The second component in avoiding fatigue and injury is proper positioning of the dental equipment in relation to the clinician. It is important that the clinician not have to bend over or reach to access dental instruments or equipment.
Position for Mandibular Teeth
1. Dental Light. Position the dental light directly above the patient's head. The light should be as far above the patient as possible while still remaining within easy reach. In this position, the light beams will shine di­rectly down into the patient's mouth.
2. Bracket Table. If the dental unit has a bracket table, it should be positioned as low as possible so that the cli­nician can easily view the instruments resting on it. Instruments should be within easy reach.
3. Patient Chair. Position the patient chair so that your el­bow angle is at a 90-degrec angle when your fingers rest on the mandibular teeth.











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Light Position for Maxillary Teeth
1. Dental Light. Position the dental light above the pa­tient's chest. Tilt the light so that the light beams shine into the patient's mouth at an angle. Position the light as far away from the patient's face as possi­ble while still keeping it within easy reach.
2. Patient Chair.When instrumentation moves from the mandibular to the maxillary teeth, lower the entire patient chair (not just the chair back) until your el­bow angle is at a 90-degrec angle when your fingers rest on the maxillary teeth.






TABLE 3. Summary Sheet: Relationship to Patient and Equipment
Clinician Chair Your thighs should be parallel to the floor and you should be able to rest your heels on the floor. your legs and the stool base should form a tripod, somewhat like the legs of a three-legged stool. This tnpod formation creates a very stable posi­tion from which to work.
Height of Patient Chair TEST FOR PROPER NEUTRAL POSITION: Fold your arms across your waist. The tip of the patients nose should be lower than your elbows.
Clinician you should not have to raise your elbows above waist level when work­ing in the patient's mouth. your lower arms should be in a horizontal position or raised slightly so that the angle formed between your lower and upper arms is slightly less than 90 degrees. In this position, your muscles are well positioned to control fine wrist and finger movements.
your shoulders should be level and should not be hunched up toward your ears.
Bracket Table Position it slightly above the patient's body. The lower the tray level, the easier it will be for you to see the periodontal instruments resting on it.
Dental Light Position the light as far away from the patient's face as possible while still keeping it within easy reach.





DIRECTIONS FOR PRACTICING THE CLOCK POSITIONS
Box 4- Directions for Sections 4 and S of this Module
POSITION FOR TREATMENT AREAS OF THE MOUTH
1. The next two sections of this module contain instructions for positioning yourself to obtain the best possible access to each of the treatment areas. For some treatment areas, there is a range of clock positions in which you can sit.
2. For this module, you should concentrate on mastenng your positioning for each treatment area. Work without dental instruments and just concentrate on learning positioning. Before picking up a periodontal instrument, you should master the large motor skills of positioning yourself, your patient, and the dental equipment to facilitate neutral position.
3. As you practice each clock position, position your arms and hands as described in this module. You will use both of your hands for periodontal instrumentation, the periodontal instrument is held in your dominant hand, and the mirror is held in your nondominant hand. For this module, practice placing the fingertips of your hands as shown in the illustration for each clock position.
4. you will not be able to obtain a clear view of all the teeth as you practice positioning in this mod­ule. In Modules and 6, you will learn to use a dental mouth mirror to view these "hidden" tooth surfaces.
5. When practicing on a classmate, use universal precautions for infection control.
RIGHT- AND LEFT-HANDED SECTIONS
The remainder of this module is divided into right- and left-handed sections.
Right-handed Clinicians: Refer to Section 4 on the following page.
Left-handed Clinicians: Turn to Section 5 on page 32.







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Position for RIGHT-Handed Clinician
Instrumentation of the various treatment areas may be accomplished from one of four basic clini­cian positions. The four basic clinician positions are usually identified in relation to a 12-hour clock face:
1. 8 o'clock position—to the front of the patient's head
2. 9 o'clock position—to the side of the patient's head
3. 10 to 11 o'clock position—near the corner of the patient headrest
4. 12 o'clock position—behind the patient's head
The four clock positions arc described in detail on the following pages.













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CLOCK POSITIONS
4 o'clock Position (to the Front)
1. Torso Position. Sit facing the patient with your hip in line with the patient's upper arm.
2. Leg Position. Your thighs should rest against the side of the patient chair.
3. Arm Position. To reach the patient's mouth, hold your arms slightly away from your sides. Hold your lower left arm over the patient's chest. The side of your right hand rests in the area of the patient's left cheekbone and upper lip. NOTE: Do not rest your arm on the patient's head or chest.
4. Line of Vision. Your line of vision is straight ahead, into the patient's mouth.
5. Hand Position. Rest the side of your right hand in the area of the patient's left cheekbone and upper lip. Rest the fingertips of your left hand on the anterior teeth in the patient's maxil­lary right quadrant.
6. NOTE: It is difficult to maintain neutral arm position when seated in the 4 o'clock position. Use of this position should he limited.












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3 o'clock Position (to the Side)
1. Torso Position. Sit facing the side of the patient's head. The midline of your torso is even with the patient's mouth.
2. 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. Neutral position is best achieved by straddling the chair; however, you should use the alterna­tive position if you find straddling uncomfortable.
3. Arm Position. To reach the patient's mouth, hold the lower half of your left arm in approximate alignment with the pa­tient's shoulder. Hold your right hand and wrist over the re­gion of patient's left eye.
4- Hand Position. Rest your right hand in the area of the pa­tient's left cheekbone. Rest the fingertips of your left hand on the premolar teeth of the mandibular left posterior sextant.
5. Line of Vision. Your line of vision is straight down into the mouth.














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2 to I o'clock Position (Near Corner of Headrest)
1. Torso Position. Sit at the top left corner of the headrest; the mid­line of your torso is even with the temple region of the patient's head.
2. Leg Position. Your legs should straddle the corner of the head­rest.
3. Arm Position. To reach the patient's mouth, hold your left hand directly* across the corner of the patient's mouth. Hold your right hand and wrist above the patient's nose and forehead.
4. Hand Position. Rest your right hand in the area of the patient's right cheekbone. Rest the fingertips of your left hand on the pre­molar teeth of the mandibular right posterior sextant.
5. Line of Vision. Your line of vision is straight down into the mouth.














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12 o'clock Position (Directly Behind Patient)
1. Torso Position. Sir directly behind the patient's head; you may sit anywhere from the left corner of the headrest to directly behind the headrest.
2. Leg Position. Your legs should straddle the headrest.
3. Arm Position. To reach the patient's mouth, hold your wrists and hands above the region of the patient's cars and checks.
4. Hand Position. Place the fingertips of your right hand on the an­terior teeth in the maxillary right quadrant. Rest the fingertips of your left hand on the anterior teeth in the mandibular left quad­rant.
5. Line of Vision. Your line of vision is straight down into the pa­tient's mouth.












QUICK START GUIDE TO LEARNING CLOCK POSITIONS
Directions: Follow the simple steps outlined below and you will quickly learn which clock position to use for each treatment area of the mouth.
Quick Start Guide to Anterior Tooth Surfaces
1. Divide Each Anterior Tooth in "Half". For instrumentation, an anterior tooth is di­vided into two halves at the midline of the tooth.
2. Sit at 4:00.
3. Determine Surfaces Closest to You.








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Anterior Surfaces Toward You when you sit at 4:00 are instrumented from the 4:00 to 3:00 position.
Anterior Surfaces Away From You when seated at 4:00 are instru­mented from the 12:00 position.








Quick Start Guide to Posterior Sextants
1. Divide Each Sextant into Aspects. For instrumentation, each sextant is divided into aspects. One clock position is used for the facial aspect of a sextant. Another clock position is used for the lingual aspect of a sextant.
2. Sit at 3:00.
3. For EACH SEXTANT, determine the Aspect Facing Toward You. For example, look at the mandibular left posterior sextant.
• The facial aspect of the mandibular left posterior sextant is facing toward 3:00.
• The lingual aspect of the mandibular left posteriors is facing away from 3:00.













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Posterior Aspects Facing Toward You when you sit at 3:00 are instru­mented from the 3:00 position.
Posterior Aspects Facing Away From You when you sit at 3:00 are in­strumented from the 2 to 1 o'clock position.




FLOW CHART: SEQUENCE FOR PRACTICING POSITIONING
For successful periodontal instrumentation, ir is important to proceed in a step-by-step manner. A useful saying to help you remember the step-by-step approach is "Me, My Patient, My Light, My Nondominant Hand, My Dominant Hand."

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POSITIONING FOR THE ANTERIOR SEXTANTS
Anterior Surfaces
TOWARD
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Anterior Surfaces TOWARD
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Anterior Surfaces TOWARD






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Anterior Surfaces TOWARD
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POSITIONING FOR THE POSTERIOR SEXTANTS
Posterior Aspects Facing TOWARD
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Posterior Aspects Facing TOWARD



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REFERENCE SHEET: POSITION FOR THE RIGHT-HANDED CLINICIAN
Photocopy this page and use it for quick reference as you practice your positioning skills. Place the photocopied reference sheet in a plastic page protector for longer use.
TABLE 4- Positioning Summary
Treatment Area Clock Position Patient Head Position
Mandibular Arch—Anterior surfaces toward 8-9:00 Slightly toward. Chin DOWN
Maxillary Arch—Anterior surfaces toward 8-9:00 Slightly toward. Chin UP
Mandibular Arch—Anterior surfaces away 12:00 Slightly toward. Chin DOWN
Maxillary Arch—Anterior surfaces away 12:00 Slightly toward. Chin UP
Mandibular Arch—Posterior aspects facing toward 9:00 Slightly away. Chin DOWN
Maxillary Arch—Posterior aspects facing toward 9:00 Slightly away. Chin UP
Mandibular Arch—Postenor aspects facing away 10-11:00 Toward. Chin DOWN
Maxillary Arch—Posterior aspects facing away 10-11:00 Toward. Chin UP
NOTE: This ends the section for the RIGHT-Handed Clinician. Turn to page 42 for Section 6: Skill Application.
REFERENCES
1. Silversrein, B.A., et al.. Work-related musculoskeletal disorders: comparison of data sources for surveillance. Am J Ind Med, 1997.31(5): p. 600-8.
2. Jacobscn, and A. Henstcn-Pettcrsen, Occupational health problems among dental hygienists. Community Deni Oral KpidemioL 1995. 23(3): p. 177-81.
3. Jacobscn, N., T. Derand, and A. Henstcn-Pcttcrscn, Profile of work related health complaints among Swedish dental laboratory technicians. Community Dent Oral
Epidemiol, 1996. 24(2): p. 138-44.
4. Mocn, B.E. and K. Bjorvatn, Musculoskeletal symptoms among dentists in a dental school. Occup Med (Lond), 1996. 46(1): p. 65-8.
5. Reitcmeier, B., Psychophysiological and epidemiological investigations on the dentist. Rev Environ Health, 1996. 11(1-2): p. 57-63.
6. Rundcrantz, B.L., B. Johnsson, and U. Moritz, Cervical pain and discomfort among dentists. Epidemiological, clinical and therapeutic aspects. Part 1. A survey of pain and discomfort. Swed Dent J, 1990. 14(2): p. 71-80.
7. Runtlcrantz, B.L., B. Johnsson, and U. Moritz, Pain and discomfort in the musculoskeletal system among dentists. A prospective study. Swcd Dent J, 1991. 15(5): p. 219-28.
8. Rundcranrz, B.L., Pain and discomfort in the musculoskeletal system among dentists. Swcd OcntJSuppI, 1991. 76: p. 1-102.
9. Silverstein, B.A., L.J. Fine, and T.J. Armstrong, Hand wrist cumulative trauma disorders in industry. Br J Ind Med, 1986. 43(11): p. 779-84.
10. Latko, W.A., et al.. Development and evaluation of an observational method for assessing repetition in hand tasks. Am Ind Hyg Assoc J, 1997. 58(4): p. 278-85.
11. Kilbom, S., et al. Musculoskeletal disorders: work-related risk factors and prevention. Int J Occup Environ Health, 1996. 2(3): p. 239-2*6.
12. Silverstein, B.A., L.J. Fine, and T.J. Armstrong, Occupational factors and carpal tunnel syndrome. Am J Ind Med, 1987. 11 (3): p. 343-58.
13. Occhipinti, E., et al.. Criteria for the ergonomic evaluation of work chairs. Med Lav, 1993. 84(4): p. 274-85.

1 comment:

Anonymous said...

Great article.
Thank you. :)

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