牙医操作标准体位

Adopting a healthy sitting working posture during patient treatment. Prof Oene Hokwerda, dentist and dental ergonomist oene.hokwerda@home.nl Rolf de Ruijter, dentist r.a.g.de.ruijter@med.umcg.nl Sandra Shaw, dentist s.shaw@med.umcg.nl 27 July 2006 1 Contents: 1 Introduction......................................................................................................2 2 Principles for working in a stabile, active posture .....................................3 3 Adopting a stable and active sitting posture. .............................................3 4 Conditions for obtaining an optimal working posture ................................4 5 Features of an optimal, healthy posture .....................................................5 6 Alternating between sitting without and with a back .................................6 7 Application of the principles for a good working posture..........................7 8 Positioning the light beam of the dental operating light parallel to the viewing direction .............................................................................................9 9 Movements of the patient’s head in three directions ..............................10 10 Positioning the patient when the dentist works from behind .................17 11 Starting position for the majority of treatment: about 11.00 o’clock position. ..........................................................................................................18 12 Applications. ..................................................................................................20 13 Sitting beside the patient, in the 8.30-10.00 o’clock position, for treatment in the lower jaw ...........................................................................23 14 Sitting beside the patient, in the 8.30-10.00 o’clock position, for treatment in the upper jaw...........................................................................25 15 Combination of a stable, active working posture with a dynamic working method.............................................................................................26 Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 1 Introduction The aim of this review is to explain the way in which different dental procedures can be carried out in the mouth of the patient whilst maintaining a healthy sitting posture. The way in which conditions for adopting this posture need to be applied is shown with the help of pictures. In order to clarify this further many examples of the ways it is possible to work in a symmetrical upright posture without overloading the musculo-skeletal structures are included. Adopting this posture prevents the high percentage of musculo-skeletal complaints which are known to affect about 65 % of dentists and are also the cause of a high percentage of disability. In the document “Requirements for working in a healthy way with dental equipment” the principles for designing dental equipment appropriate to work in a healthy way are specified. These principles are derived from: · ISO Standard 6385 “Ergonomic principles in the design of work systems”. · ISO Standard 11226 ”Ergonomics – Evaluation of static working postures”. · Working postures and Movements. Tools for Evaluation and Engineering. Editors: Delleman NJ, Haslegrave CM and Chaffin DB. New York, Washington: CRC Press LLC, 2004. This book contains a review of recent research. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 2 Principles for working in a stabile, active posture The basic principles for working in a stable, active sitting posture are: 1. to sit in a relaxed, symmetrical posture upright with the arms against the upper body which minimizes the static load of upper arms and shoulders. Furthermore the movements of the upper arm both sidewards and forwards must be minimized as much as possible, sidewards being within 15-20° and forwards within 25 °. The upper body can be bent forward from the hip joints to a maximum of 10-20° but bending sideways/laterally and rotations should be avoided. The head can be bent forward maximally 25°. 2. to aim for a dynamic way of working: making movements with the body during patient treatment as much as possible so that an alternating load and relaxation occurs within the muscles and the vertebral column. 3. to ensure a firm muscle corset by sport and or movement outside office hours thus ensuring recovery of the burdened muscles and increasing the muscle strength, which in turn result in being better able to maintain a correct posture. This issue will not be dealt with in this document. 3 Adopting a stable and active sitting posture. For adopting a stable, active sitting posture, from which movements can easily be carried out, the operator sits symmetrically upright, with the breastbone pushed slightly forwards and upwards and the abdominal muscles strained slightly. The shoulders are above the hip joints and the line of gravity runs through the lumbar vertebrae and pelvis in the direction of the seat. This posture facilitates good breathing. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 4 Conditions for obtaining an optimal working posture Conditions for obtaining an optimal, stable working posture are the following: 1. sit in a stable upright working posture. 2. place the working field in the mouth straight before the upper body in the symmetrical plane. This is the mid-sagittal plane that divides the body vertically in 2 equal parts. 3. look as much as possible, perpendicularly upon the working field. If this does not happen the eye balls steer the head until it reaches this position and then the body posture changes automatically. In this way the eye balls come into the position of looking perpendicularly upon the working field as much as possible. This results in a unfavourable bent posture that is asymmetrical whenever the working field lies outside the symmetrical plane, this frequently happens. You may compare the position of the working field in the mouth of the patient with the position in which you hold an apple when peeling it or a needle when preparing to thread it: you will hold these straight before your upper body without bending your head. Further the oblique position you hold your book when sitting in a chair to read (with the lamp besides/behind you) gives you an impression of how to place the working field so as to be able to look about perpendicularly upon it. By turning the head of the patient within the three planes it is possible to place the working field in the symmetrical plane of the operator and the surface of the tooth dealt with has to be turned towards the viewing direction. In other words: this surface is positioned parallel with the front side of the head of the dentist. Looking about perpendicularly upon the working field or mirror is like reading a book. Height of working field: the place for handling instruments in the mouth. Lower arms lifted 10-25°. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 5 Features of an optimal, healthy posture · Sitting as far back as possible in the seat to obtain a stable posture, symmetrically upright. · Upper arms alongside the upper body to support the arms whilst carrying out treatment. · Angle between lower and upper legs of about 110° or a little more, with the legs slightly spread. · Working height adjusted properly, with the lower arms lifted a little from about 10° to a maximum of 25°. · Distance between working field in the mouth and eyes or spectacles normally between 35 –40 cm. · The back must be supported at the upper/backside of the pelvis so that as soon as the muscles become too fatigued to maintain an upright position of the back, the back-rest ensures that the desired upright posture can be maintained. This supporting has to occur without pressure against the muscles below and above this point. Because the posture becomes unfavourably influenced by this and a reduction of movements takes place. · Instruments are handled with the modified pen grip: with the first 3 finger bent in a round form around the instrument and the last 2 fingers resting on a firm basis in or outside the mouth. This posture is mandatory for a healthy way of working. Side view working posture. Frontal view working posture. In order to support the horizontally positioned bottom and the obliquely sloping down thighs equally, when sitting with an angle of 110° between upper and lower legs, the rear 20 cm of the seat should run horizontally and the front 20 cm downward with an angle of 20°. 10°-25° =110° 35 – 40 cm Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 6 Alternating between sitting without and with a back An important principle is to use a dynamic way of sitting. This can be realized by sitting alternately with and without a support for the upper/backside of the pelvis by a back-rest. Begin by actively sitting upright with the breastbone pushed forward and upward, the abdominal muscles strained slightly and the upper body- if necessary bent slightly forward with an angle of not more than 10°. As long as it is possible to maintain this posture, also depending on having a well trained muscles, one may work without supporting the pelvis. The advantage of this is that one is then able to move the body more easily. But this posture requires muscle strength and this leads sooner or later to normal phys iological fatigue by which it is no longer possible to maintain the upright posture. However a considerable variation exists in maintenance time. As soon as fatigue occurs and one starts as a consequence of this to sit with a backward bent back - a so called C-back – support of the back-rest against the upper/backside of the pelvis becomes necessary to avoid sitting in an unfavourable, damaging posture. It is essential that the back support only lies against the lower part of the back curvature (lordosis) and that contact is avoided with back and backside muscles, respectively above and below the support of the pelvis at the upper/backside. Further it is important that the back-rest is fixed so far forward that the natural curvature (lordosis) is actually maintained and it is not possible for the back to bent backward. Finally the back-rest upholstery needs to have sufficient flexibility for agility. Sitting posture without leaning against back-rest. The movement forward with the back is made from the hip joint. A backward bent C-back is avoided so that a natural curvature is maintained. Sitting posture whilst leaning against back-rest. A natural curvature of the back is also realized here. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 7 Application of the principles for a good working posture Working field straight before the upper body, in the symmetrical plane. An unfavourable posture arises spontaneously when the working field is placed outside the symmetrical plane. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 Look perpendicularly as much as possible onto the working field from a correct posture. Otherwise the eye balls steer the posture into an unfavourable, mostly asymmetrical position to achieve this. The working field is not adjusted perpendicularly to the direction of the line of vision thus the operator automatically adopts an unfavourable posture. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 8 Positioning the light beam of the dental operating light parallel to the viewing direction The aim is to position the light beam of the dental operating light parallel with the viewing direction in order to obtain shadow free lighting and a good balance between lighting in the working field and in the mouth as a whole. This avoids the fatigue forming shadows from the hands, teeth, lips and cheek being seen on and around the working field. To achieve this the dental operating light needs to have 3 (orthogonal) axes which then enables the lamp to turn in all directions to achieve the desired position next to the head of the dentist and avoid placing the lighting rectangle obliquely over the face of the patient which is uncomfortable for him/her. Position of the lamp for a right handed dentist, when sitting behind the patient: in principle on the left, slightly above and to the side next to the head of the dentist (for left handed dentists in mirror image). When the lamp is placed on the left side: shadows will be formed under the right hand and instrument. 15° 45° Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 When sitting at the side of the patient chair: mostly on the right side. 9 Movements of the patient’s head in three directions The patient’s head must be moved in three planes in order to achieve the correct position of the working field for: · positioning the working field in the mouth in the symmetrical plane of the dentist; · looking on it perpendicularly as much as possible. Survey three movements of the head. First movement: forward with occlusal surface lower jaw horizontally, about 0° or turning backward with occlusal surface upper jaw 20-25° backward Second movement: lateroflexion to the left or to the right, about 30° Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 Third movement: around the length axis of the head of the patient tot the left or to the right, maximally 45° N.B. Take care to provide good support underneath the neck at the right place. The head support or pillow plays an essential role at this. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 Lower jaw Moving the head forward: occlusal plane lower jaw approximately horizontal when the dentist is working in the 9.00-10.00 o’clock position in the lower jaw. The back is positioned slightly obliquely, the pillow is positioned backward and the chin is directed towards the breast. Without placing the occlusal plane approximately horizontally while working in the lower jaw the right arm has to be lifted to be able to position the handpiece or scaling instrument in the right position. The head of the dentist is bent sideward for a good sight. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 The occlusal plane of the lower jaw is slightly turned backward in relation to the operator at an angle of about 35° for treating the lower teeth in the front, with the pillow positioned slightly further back while the chin is directed towards the breast. The axes of the lower teeth are directed toward the viewing direction. The occlusal plane of the lower jaw is turned backwards, about 40 °, for treating the premolar region. The occlusal plane is turned further backwards, about 45°, to be able to look at the molars without bending the upper body. 35°-40° 40° 40°-45° Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 Upper jaw Tilting the head backwards: occlusal surface of the upper jaw 20-25° backwards in relation to the vertical plane to be able to look approximately perpendicularly at the incisors, like reading a book. The incisors are so positioned to make an angle of 20-25° upwards. Idem for working with indirect vision with a mirror in an oblique position to be able to look upon it more or less perpendicularly, like reading a book; with the light beam parallel with the viewing direction and as far as possible perpendicular to the mirror. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 If it is not possible to turn the head of the patient with the occlusal surface of the upper jaw sufficiently backwards, after positioning upper body and head of the patient horizontally, the head can usually be turned in the desired position by pressure with a finger behind the upper incisors.. To turn the head of the patient in lateroflexion about 30°, obliquely sidewards to the right or the left, the patient is requested to lift his head. The dentist then places the pillow in an oblique position about 4 cm sidewards because the neck is moved sidewards. Then the head of the patient is guided sideways onto the pillow into the desired position. This movement is necessary in order to place the working field in the symmetrical plane and to be able to look upon it approximately perpendicularly. It is explained more extensively further on. Lateroflexion is the most ignored movement of the patient’s head. This is also frequently the consequence of unsuitable headrests. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 Turning the head of the patient around the length axis to the right or the left is used to complete the movements of the head to obtain the desired position or final position of the working field in the mouth. It results in fine tuning of the positioning of the working field with respect to the viewing direction, when seated in the proper posture. Without a lateroflexion this is generally not possible and subsequently leads to bending and rotating of the upper body and head of the dentist. Lateroflexion to both the right and to the left should be used by both right and left handed dentists. Optergo Ltd | www.optergo.co.uk | info@optergo.co.uk | T: +44 207 234 96 48| F:+44 207 403 80 07 Optergo AB | www.optergo.com | info@optergo.com | T: +46 31 88 77 27 | F:+46 31 88 39 77 10 Position