Magnification Basics

The dental hygienist’s working area is extremely small–a patient’s oral cavity. As a result, dental hygienists must reposition their backs, necks, and shoulders throughout the day to provide effective treatment. Awkward positioning and retaining static postures can lead to musculoskeletal disorders (MSDs), a combination of problems that affects muscles, ligaments, nerves, tendons, bones, and joints.¹ Musculoskeletal pain affects 64% to 93% of all dental professionals with the neck, back, and shoulder being the most frequently cited areas of pain.^2,3

ETIOLOGY

Poor posture is the most common cause of back, shoulder, and neck problems in dental hygienists.^3-7 Since visual acuity is essential during dental hygiene care, dental hygienists often fail to follow appropriate ergonomic principles in order to improve their vision of a patient’s mouth. Many clinicians bend their necks, work in unbalanced forward positions, and align themselves too far forward. These postures can cause stress on ligaments and muscles, leading to musculoskeletal pain.^4-7 Dental hygienists must perform their daily tasks with a straight supported back and shoulders to decrease their risk of MSDs.⁵ The use of magnification in everyday practice can help dental hygienists maintain correct posture.²

The use of properly adjusted loupes improves the clinician’s field of vision, thus reducing the risk of postural compromise in the neck, back, and shoulders.^8-10 Loupes can assist dental hygienists during all phases of patient assessment and treatment, including hard- and soft-tissue evaluation, periodontal instrumentation, and radiographic interpretation.^11,12 However, the use of poorly selected or fitted loupes may increase the risk of MSDs. Choosing the right pair of loupes is paramount to the tool’s success.¹³

MAGNIFICATION SYSTEMS

Loupes are the most common type of magnification used in dentistry. Clinicians interested in purchasing a magnification system should consider a loupe’s declination angle, working distance, and depth of field. Figure 3 provides definitions and illustrations of loupe terms.¹³ A comfortable, ergonomically-correct declination angle will force clinicians to incline their heads less downward, supporting their skeleton. The working distance is another vital factor that forces the clinician to work with less neck flexion and in a more upright position. Depth of field is equally important to consider because this provides the clinician with range of movement while maintaining the same focus.¹²

There are several types of loupes available, however, only three types are used by dental hygienists: fixed through-the-lens, front lens mounted (FLM) without vertical adjustment, and FLM with vertical adjustment. Through-the-lens loupes are directly mounted on the lens of the glasses. This type of lens cannot be adjusted because of the fixed declination angle, which forces the clinician to work in an ergonomically correct posture. Through-the-lens loupes tend to be lightweight. Vision correction must be incorporated into the lenses. FLM loupes without vertical adjustment have lenses affixed to the frame so they can be flipped up or down. The interpupillary distance is adjustable so these loupes can be easily used by different clinicians but the angle of declination cannot be adjusted.¹³ These loupes tend to be heavier than through-the-lens models.¹⁴

The declination angle can be adjusted in FLM loupes with vertical adjustment. They typically have a mounting fixture with double hinges and vertical slide so the angle can be changed for different dental hygiene tasks.¹³

CONCLUSION

Work-related MSDs of the neck, shoulder, and back among dental hygienists are most commonly caused by improper posture. One approach to minimize the risk of MSDs is the use of loupes. When properly fitted and used, loupes can help clinicians sit in a more natural position with less neck flexion, thereby improving posture.

REFERENCES

1. Hayes MJ, Cockrell D, Smith DR. A systematic review of musculoskeletal disorders among dental professionals. Int J Dent Hyg. 2009;7:159-165.
2. Anton D, Rosecrance J, Merlino L, Cook T. Prevalence of musculoskeletal symptoms and carpal tunnel syndrome among dental hygienists. Am J Ind Med. 2002;42:248-257.
3. Öberg T, Öberg U. Musculoskeletal complaints in dental hygiene: A survey study from a Swedish county. J Dent Hyg. 1993;67:257–261.
4. Öberg T, Karsznia A, Sandsjö L, Kadefors R. Work load, fatigue, and pause patterns in clinical dental hygiene. J Dent Hyg. 1995;69:223–229.
5. Lalumandier JA, McPhee SD, Parrott CB, Vendemia M. Musculoskeletal pain: prevalence, prevention, and differences among dental office personnel. Gen Dent. 2001;49:160-166.
6. Morse T, Bruneau H, Michalak-Turcotte C, et al. Musculoskeletal disorders of the neck and shoulder in dental hygienists and dental hygiene students. J Dent Hyg. 2007;81:10.
7. Marklin RW, Cherney K. Working postures of dentists and dental hygienists. J Calif Dent Assoc.2005;33:133-136.
8. Branson BG, Black MA, Simmer-Beck M. Changes in posture: A case study of a dental hygienist’s use of magnification loupes. Work. 2010;35:467-476.
9. Branson BG, Bray KK, Gadbury-Amyot C, et al. Effect of magnification lenses on student operator posture. J Dent Educ. 2004;68:384-389.
10. Maillet JP, Millar AM, Burke JM, et al. Effect of magnification lenses on dental hygiene student posture. J Dent Educ. 2008;72:33-44.
11. Syme SE, Fried JL, Strassler HE. Enhanced visualization using magnification systems. J Dent Hyg. 1997;71:202-206.
12. Sunell S, Rucker L. Surgical magnification in dental hygiene practice. Int J Dent Hyg.2004;2:26-35.
13. Branson B, Simmer-Beck M. Visual acuity without injury. Dimensions of Dental Hygiene. 2009;7(9):46-49.
14. Draper C. Magnification and Illumination. Access. 2010;24(5):20-22.

From Dimensions of Dental Hygiene. November 2010; 8(11): 36-38.