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Ergonomics and Operatory Equipment Systems
Lance M. Rucker, DDS
Technology’s Impact on the Dental Practice
The dental profession has had a long history of unhealthy compromises of postures in order to adapt to chairs, units, and other equipment systems as they are applied in patient care. These compromises are in part reflected in the epidemic proportions of work-related musculoskeletal symptoms (WRMSSs), which have afflicted dentists, dental hygienists, and dental assistants. In the past 30 years we have witnessed a creative explosion of chairside delivery devices that perhaps have the potential for neutralizing many of these compromises.
However, during this same time period, the pattern and incidence of WRMSSs of dentists has not altered. Published studies in the past 6 years clarify that dental students show the same symptom and breakdown patterns, even though they are operating at much lesser intensity than they will when they graduate. Similar studies confirm this profile of avoidable symptom patterns for dental hygienists. Yet, studies from 2001 indicate that most of clinicians’ pain symptoms are avoidable by using appropriately selected and utilized surgical magnification, and by having a basic understanding of applied clinical ergonomics.
The basic level of clinical ergonomics education in dental schools and faculties of the world is woefully low. Most clinicians only become interested in optimizing their settings and the ways in which they use them when they encounter pain and move beyond the professional myth that says, “that’s just the way it has to be when you are doing clinical dentistry.” If your operatory equipment isn’t working for you, then you are certain to be working for your operatory equipment.
More and more, dental manufacturers have sought to fully integrate new technology into “plug-and-play” formats so that as soon as a new technology has evolved to general use, it no longer haphazardly clutters the working operatory (eg, light-curing units, intraoral camera units, laser wands, etc). Ergonomists seek technology that is economical enough to be deployed and positioned identically for use in every operatory. Ideally, there should be no postural accommodation of the clinician required in order to diagnose, plan treatment, and operate.
Ubiquity of computer technology for chairside digital management of patient records, including radiographic and other imaging, suggests the need for optimal positioning of computer input and output devices. We are headed toward hands-free chairside computer input, with full voice-recognition software available for reliable input of chairside charting and observations. For this, it would be ideal to have the output (eg, the computer screen) embedded in our spectacles (eg, eyes-up to a virtual screen). Alternatively, we can accept a screen that is at or below eye level, so that all input data could be checked for accuracy and digital images studied chairside as needed. It will be especially important that operatory furniture (eg, patient chair, surgical microscope, etc) can be adjusted by voice to command intelligently delivered coordination of movement of the furniture to optimize operator access and neutralize operatory compromises of posture.
We currently have the technology to do this, and such seamless integration of our technologies is on the horizon, but not yet commonly available in most offices of the world. By and large, replete with an arsenal of new technologies, most clinicians still work for their equipment.
Ironically, most modern delivery systems allow operatory layouts that achieve the ideal we seek, but designers and installers are woefully unaware of the distinction between “fully equipped” (ie, has everything you might want) and “optimally deployed” (ie, has what you need, when and where you want it). So, many modern practices end up as spotty collections of new and older technologies, collaged together in ways that defy balanced operation. Often, too, operatories of multi-operatory practices are so functionally different that an even, efficient flow of patient care is impeded.
Lightweight, wand-type fiber-optic curing lights now appear in many delivery system plug-and-play configurations, and light-emitting diode (LED) curing technologies are becoming portable enough to be delivered from the instrument tray as just another lightweight hand instrument.
Digital acquisition units (eg, for direct or indirect milling equipment usage) are becoming sufficiently portable for plug-and-play delivery but, for the most part, offices continue to deploy these units as stand-alones that occupy precious floor or countertop space so that their use invites (if not demands) compromises of position and postures by dentists and their assistants.
Surgical magnification has three non-negotiable requirements for achieving ergonomic balance, whether it is using single-lens magnification, multi-lens telescopes (loupes), or surgical microscopes:
1. Optical working distance, which matches the clinician’s optimized musculoskeletal proprioceptively derived operating position of field for a person.
2. Declination angle of the telescopes that matches the clinician’s derived optimized preference for head and eye declinations.
3. Co-axial viewing through the scopes when they are set to the optimal declination angle for the user. Many manufacturers’ products seemingly have a wide range of adjustment of declination, but a very small range of vertical adjustment to allow true co-axial viewing. This problem results in optical errors and increases likelihood of clinician error.
Using current surgical microscope systems, clinicians will compromise with a slightly forward posture for their upper bodies, leaning toward the oculars rather than resetting the equipment to their own balanced operations.
Direct-to-screen digital viewing devices can present limitations vis-à-vis mirror usage for areas of the oral cavity. It also creates control problems because it separates the perceived (on-screen) operating point from the proprioceptively sensed intraoral operating site.
The key to optimized ergonomics in the dental operatory may be an integrated motorized headrest that is driven by ergonomic software modules so that the operatory furniture becomes truly hand-adjustment-free from the beginning of a procedure to the end (through the variety of access positions which may be called for). Such software technology has been prototyped, and the software is under development to provide such headrests for aftermarket installation, which will include chair control and integration firmware in the headrest itself.
The great news is that most modern operatory equipment systems can permit balanced ergonomics for clinical operation if properly installed. The bad news is that due to improper installation or adjustment, or limited ergonomics sophistication of clinicians, most go out of balance and distort their bodies to accommodate their equipment. The evolution of intelligent operatory equipment systems gives hope that within 10 years, our operatory equipment will be designed to default to optimal ergonomics for both clinician and assistant.