degrees).⁷ The further the head is positioned forward to see through the loupes, the greater the strain on the neck muscles and discs.⁸,⁹
Most flip-up loupes have a much better dec- lination angle than through-the-lens loupes. When assessing flip-up loupes, keep in mind that telescope position is critical. You can have loupes with the best declination angle on the market, but if they sit high in relation to your pupil, you will lose much of the ergo- nomic benefit, because you must lean further forward to look through the scopes. There- fore, vertical adjustment is an important feature with flip-up loupes. Some companies achieve this with a vertical slide mechanism (Fig. 2), a series of vertical mounting holes, or an ‘extender’ that greatly improves declina- tion angle.
If you do opt for TTL loupes, a pantoscopic tilt feature can help ensure the best declina- tion angle. A pantoscopic tilt feature angles the bottom of the lenses back toward the cheek which tilts the scope downward and makes the angle smaller. Also, some compa- nies achieve a pantoscopic tilt by means of a ratcheting hinge mechanism on the arm of the frame. (Fig. 3) Sports frames, by design, typically have a small amount of pantoscopic tilt built into them. It is generally a good idea, when ordering TTL loupes, to request the steepest declination angle possible.
The worst declination angles I repeat- edly measure, both clinically and in dental schools, are long barrel (high magnification, prismatic) scopes mounted in through- the-lens frames. (Fig. 4, left) It is extremely difficult for manufacturers to achieve even a fair degree of declination angle with this combination. Furthermore, the heavy weight of the long barrel exponentially increases the forces on the cervical spine when combined with poor declination angle. From a purely ergonomic standpoint, long barrel scopes are best mounted in a flip-up style loupe. (Fig. 4, right)
Working distance: The working distance is the distance from the eyes to the working area. If the working distance is measured too short, it can result in excessive neck flexion or hunching.¹⁰
FIG. 3: Declination angle is improved on TTL loupes via a pantoscopic tilt, achieved by two mechanisms: Ratching hinge (left) and frame angle (right). Photo ©2011 Posturedontics, LLC
FIG. 4 Left: Long barrel (Keplerian or Prism) scopes mounted in TTL frames, resulting in sub-optimal declination angle (28 degrees) excessive forward head posture and rounding of the upper back. Right: Long barrel scopes should be mounted in a flip-up style loupe to obtain an adequate declination angle (50 degrees) that allows safe head posture. Photos ©2011 Posturedontics, LLC
If possible, measure the working distance in your own operatory, with a patient in the chair. Sit in neutral operating position look- ing into the patient’s mouth, with the oc- clusal plane at, or slightly above, elbow level. Have someone view you from the side and measure the distance from your eye to the work surface, or tooth. Working distances will vary for shorter operators (14 inches or less) to extra long working distances for very tall operators (more than 20 inches). There- fore, working distance should be tailored to the individual.
Frame size and shape: Keep in mind that the lower the manufacturer can place the scope in relation to your pupil, the better declination angle they usually can achieve. Large frames that sit low on the cheek will allow lower placement of the TTL scope than smaller oval frames. In general, flip-up loupes will sit lower in relation to the pupil than TTL loupes. When placing your order, it is a
good idea to request that the TTL scope be placed as low in the large frame as possible.
Well-designed loupes can significantly improve posture and therefore help pre- vent numerous musculoskeletal disorders (MSDs) to which dentists are prone. How- ever, prolonged, static postures and weak postural muscles still can contribute to pain syndromes and MSDs.¹¹ By combining ergo- nomic magnification with chairside stretch- ing, positioning techniques and postural strengthening, the multi-factorial problem of can work-related pain in dentistry can most effectively be addressed.
Ergonomic loupes reviews: With each loupes manufacturer touting its ergonomic benefits, selection of dental loupes can be a confus- ing task. By combining the above selection guidelines with unbiased ergonomic loupes reviews, you can optimize your chances of
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