The Ergonomic Advantages

Gerard M. Cuomo, DDS, is a graduate of Northwestern University Dental School, and is a recognized author and lecturer on the integrated use of chair-mounted microscopes in dentistry. He maintains a private practice in Boca Raton, Florida, and teaches hands-on dental microscopy courses for dentists and students throughout the U.S.

The modern dental practice incorporates office designs that create an “at-home” atmosphere while using “high-tech” equipment to promote improved efficiency and increased productivity. The purpose of this article is to analyze the ergonomic and economic advantages of the dental microscope over the now obsolete dental loupes. In order to appreciate the benefits of this 21st-century equipment, one must understand the distinctions between posture-directed and image-directed dentistry.

The term “ergonomics” is the applied science of equipment design for the workplace with the intent of enhancing productivity by reducing operator fatigue and discomfort. An ergonomically designed product implies that a device must blend smoothly with a person’s body and actions. To understand equipment design, one should initially recognize the fact that certain risk factors such as poor body positioning and its related repetitive movements can alter the ergonomic purpose, thus contributing to pain and injury over time to various parts of the dental professional’s body. Musculoskeletal disorders such as herniated discs of the lower back and rotator cuff impingement are the end products of trying to work more efficiently while ignoring the proper pathways to maintain muscle balance. (8,9)

Mechanisms related to muscle balance can be explored by first understanding the differences between posture-directed dentistry and image-directed dentistry as each relates to the ergonomic well-being of the dentist. 5 “Image-directed” dentistry is associated with dental procedures performed by using a “direct line of sight.” A good example of “image-directed” dentistry is the dentist viewing an oral image by using dental loupes (Figure 1).  In this instance, the eyes are looking directly at the image through various lenses aligned with one another attached to a frame. The head posture of the loupe wearer remains in a constant tilt position with the chin angled downward. Typically, the dentist’s head moves toward the image to find and maintain focus at a set focal length.

As the image moves out of focus, it is only natural for one to refocus by moving their head back inline with the image. As the need to increase magnification becomes apparent when going from 2.0X to 6.0X, the loupe lens size becomes larger and heavier while the field of view becomes smaller. Dental loupes add an additional amount of weight to the front portion of the dentist’s head, therefore requiring straps to secure the loupes to the back side of the head to maintain stability. 1–2,5,7 In other words, the image dictates the movement of the dentist’s head, as shown in Figures 2 and 3.

“Posture-directed” dentistry is associated with dental procedures that are performed by using an “indirect line of sight.” 5 The best way to achieve “posture-directed” dentistry is by viewing an oral image using a dental microscope (Figure 4). Here the eyes are looking indirectly at the image through various lenses and prisms aligned with one another and supported by a mechanical arm apparatus. It is the use of the microscope’s inclinable binocular eyepieces that permit the dentist to raise his or her chin in a more level position. The optics of dental microscope bend the path of the image to almost 90 º, allowing the dentist to sit comfortably erect with the head, neck, and back arranged in a straight line when viewing an object. (3,10)

Posture-directed dentistry also includes several techniques for maintaining focus. The simple method of reclining the patient’s head backward into a more healthy ergonomic working position helps to form the foundation of the workplace. Posture-directed dentists rest their patients in the supine position for maxillary arch procedures and in a semisupine position for mandibular arch procedures. The dentist’s seating zone is usually in the 11 and 12 o’clock positions (Figure 5).

Figure 6

This ergonomic positioning helps the dentist avoid twisting and turning movements when using the microscope and receiving hand instruments. As the image moves out of focus, the dentist relies more on verbal commands directed toward the patient to move the image back into focus (Figure 6). (2,3,5)

Other focusing methods of posture-directed dentistry include use of the dental microscope’s fine-focus adjustment when changing magnification from 2.0X to 20X.6 In addition, the hands, the forearms, and the shoulders are often well supported by stools with built-in adjustable arms. In order to achieve posture-directed benefits, the dentist must first be willing to accept the need for change and give up old image-directed bad habits.

Dental school undergraduate curriculums teach image-directed techniques. Today’s dental students migrate from using no magnification to using dental loupes during their four years of undergraduate studies. The combination of using dental loupes with only limited four-handed dentistry available creates a breeding ground for the formation of bad habits. Based upon this fact, image-directed habits are primarily formed in dental schools and continue to shape the ergonomic foundation of the dentist’s method of practice.

Figure 7

Postgraduate endodontic curricula currently accept and require microscope proficiency of graduate students. Even though posture-directed dentistry has minimal acceptance in dental school restorative curricula, one can anticipate a change will occur with the increasing number of practicing dentists transitioning to dental microscopy. (4)

At the time this article was written, pre-dental students attending Florida Atlantic University participated in their first hands-on dental microscope course without having any previous dental microscope experience. Each of the four students was given a molar to perform a root canal. They were then instructed to restore the same tooth using current composite modalities.

Figure 8

These new generations of students are more open to accepting advances in technology. Following the single-tooth exercise, each student was asked to prepare teeth on the mannequin’s head (ergonomically placed) in the dental chair using the various posture-directed techniques previously discussed in this article. The end result indicated that all four pre-dental students had achieved an acceptable basic level of proficiency within four hours by using the dental microscope (Figures 7 and 8). This exercise clearly supports the “law of primacy” which states, “Things first learned are best remembered.”

Despite the fact that many innovative ideas such as computer software and hardware, digital X-rays, automated perio-probes, and image capturing devices have helped to modernize the dental industry by saving time, none of them have had as much ergonomic effect on dentists than that of the dental microscope. 10 Use of a dental microscope improves the dentist’s overall performance.

Figure 9

Connected to flat-screen monitors located in each operatory, the dental microscope visually adds a whole new dimension for viewing and recording real-time images.

It is this combination of microscope optics and video that have a tremendous effect on the profitability of the dental business. Dental assistants and patients now have a front row seat to viewing the dentistry being performed at several levels of magnification (Figures 9 and 10).

Figure 10

Dentists who use microscopes are able to see more and do more dentistry. One can detect early crack formation which will ultimately determine the type of restoration to be placed. (4,11) Dentists are able to find hidden calculus around margins much more precisely prior to impression taking. They are able to makemore accurate determinations on whether to use sealants, flowables, or composite resins for conservative dentistry. Final preparation design can be easily placed without compromise.(11,12)

Today’s dental microscopes can be mounted via ceiling, wall, or a more ergonomic space-saving chair-mount. Aside from ergonomic advantages, the dental microscope user enjoys shadow-free coaxial lighting and the ability to detach and transport the microscope head between workstations and office (portability).

In summary, vision in dentistry makes up the very fabric that determines how successful we become as dentists. It is our choice to practice with either yesterday’s technology, or wake up to the advances of the 21st century with an exciting new way to practice dentistry. Current and incoming students are more tech savvy than previous generations. Not only do they accept new technologies, but they go out of their way to look for them. Having been exposed early to eye-hand coordination teaching tools such as Play Stations and Xboxes, their skills have been honed, and they are ready to take on advanced magnification methods.

Dr. Cuomo and Students

Experienced dentists need not fear this new technology either. Technology should be embraced as an opportunity rather than an impediment. With proper instruction, repetition, and a willingness to learn, the practicing dentist can enjoy all the benefits of the dental microscope. Posture-directed dentistry is the logical progression for the industry. Those who make the transition to microscopy early on, will realize the distinct advantage they have over those who have not made similar choices

The author acknowledges Gerard J. Cuomo (writing consultant), Maria Martinez (dental assistant), and Florida Atlantic University (pre-dental students): Ashley Millstein, Salvatore Colombo, David Miller, and Justin Grossmayer.

1. Friedman MJ. Magnification in a Restorative Dental Practice: From Loupes to Microscopes. Compend Cont Educ Dent 2004; 25:48–55.

2. Sheets CG, Paquette JM, Hatate K. The Clinical Microscope in an Esthetic Practice. J Esthet Restor Dent 2001; 13:187–200.

3. Friedman MJ, Landsman HM. Microscope-Assisted Precision (MAP) Dentistry – A Challenge for New Knowledge. J Calif Dent Assoc 1998; 26:900–905.

4. Garcia A. Dental Magnification: A Clear View of the Present and a Close-up View of the Future. Compend Cont Educ Dent 2005; 26:459–463.

5. Cuomo GM. A Fresh Look at the Biomechanics of Advanced Magnification. Dent Econ 2004; 94:66–69.

6. Nase JB. Enhanced Vision in the Improvement of Patient Care. Dental Collab 2005; 2:19–20.

7. Pace SL. Seeing Through the Eyes of Magnification. Contem Dent Assist 2005; 2:14-18.

8. Valachi B, Valachi K. Mechanisms leading to Musculoskeletal Disorders in Dentistry: J Am Dent Assoc 2003; 134:1344–1350.

9. Valachi B, Valachi K. Preventing Musculoskeletal Disorders in Clinical Dentistry: J Am Dent Assoc 2003; 134:1604–1612.

10. Kotlow LA. Using a Dental Operating Microscope in a Pediatric Dental Practice: Compend Cont Educ Dent 2004; 25:482–488.

11. van As GA. The Use of Extreme Magnification in Fixed Prosthodontics. Dent Today 2003; June:93–99.

12. Clark D. Do Traditional Sealants Have a Place in the New, Super-Magnified World? Dent Today 2004; Sept:92, 94–98.