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Enhanced Visualization with Lens Systems: Loupes and Microscopes
Choosing the right system for your clinical and ergonomic needs
All aspects of dentistry require excellent visualization. Excellent treatment of our patients requires that dentists see fine details during examinations and procedures. In a digital world of high tech, low-tech use of lens-based magnifying systems allows clinicians to see better and make better clinical decisions.1-6
Visual acuity is critical for good, sound clinical decisions-making.7,8 As people age, visual acuity changes, which typically requires the use of corrective lenses and magnification to compensate for any visual deficiencies.7,8 In the desire to enlarge the object the dentist is viewing at the dental chair, the practitioner may move closer to the object and bend over to see better. Unfortunately, this change in position compromises posture and can create stresses and abnormalities in the musculoskeletal system that will put the dental professional at risk for back, shoulder, and neck pain.1,6,9-11 Vision influences a clinician’s posture when performing dental procedures. Poor posture is seen among practitioners of all ages and directly influences the presence and degree of musculoskeletal pain. An ergonomic approach to dental practice should include a lens-based magnification system to not only see an increased image size for improved decision making but also to contribute to improved posture. Those who wear loupes have a significantly more neutral focal distance and upper-arm abduction postures12 and thus are less likely to experience musculoskeletal disorders.13
Considerations for Selecting a System
First and foremost, the selection and use of magnification systems is not one-size-fits-all.6 When evaluating a magnification system to purchase, it is advisable to work with the device for a period of time before making a final decision. The dental professional can choose magnification systems ranging from binocular magnifying loupes to surgical microscopes. Binocular telescopes, which are the most popular, include a surgical telescope and a diopter, single-lens, flat-plane loupe.
True magnification of images is offered with surgical binocular multiple-lens telescopic loupes. These systems provide for larger image sizes with working distances compatible with ergonomic postures.1,6,11 The newest surgical telescopic loupes have multiple configurations so they can be selected with variations in working distance and an expanded selection of magnification ranging from 2.0X to more than 4.0X. Recommendations based upon ergonomic studies suggest that the working distance for dental practice, or the distance from the eye to the treatment area, should be within 35 cm and 45 cm (13.7 inches and 17.7 inches).14
In recent years, the use of surgical microscopes has become a standard for endodontists, periodontists, and restorative dentists.1,3,15-17 These systems offer true magnification ranges and not a single value. Depending on the system, the surgical dental operating microscope can have ranges of magnification from 2.0X to 20.0X or greater. Surgical microscopes may have fixed or movable stands that allow for practicing with an ergonomically correct posture, and built-in illumination is standard. Typically, these systems have adapters to allow for photographic and videographic documentation and projection. For any magnification system selected, a practitioner may have a learning curve in adapting to its use, so taking a 1- or 2-day course before purchasing a system is suggested.16 These authors would recommend that a clinician with a surgical microscope also consider having a binocular loupe.
Whether one chooses a binocular telescopic loupe or surgical microscope, the practitioner should understand some key terms and use them when questioning the manufacturer to allow for an appropriate selection of a system.6 The dentist should inquire about the optical quality and the coatings of the lenses used in a system. As described earlier, the practitioner should be measured for his or her optimal working distance. As magnification increases, the field of view will decrease, making this an important aspect to keep in mind. A system that allows the clinician to see only one or two teeth at a time could present a limitation when treating patients if the dentist wishes to see the whole quadrant. This could also be important if the subject is not stationary (pediatric or special-needs patients). Some systems have expanded fields of view for higher magnifications. Depth of field is the ability to have multiple objects in focus in the field of view. One should select a loupe or microscope with the greatest depth of field for the power of magnification desired.
Working angulation and visual angle of the system being selected should allow the dentist to optimize working posture. The clinician who is evaluating a system should try it while working with real tasks and not just evaluating the size of the image. For binocular telescopes, many systems have either fixed lenses or a flip-up capability for the telescopes. Fixed-lens magnifiers have the advantage of not needing to be adjusted during a procedure. These systems can be fabricated with a working angulation and visual angle that is optimal for the clinician’s posture. Flip-up systems can be adjusted chairside. Other considerations for binocular loupes are the weight of the loupe and the fit of the glass frames. Glass frames must fit the nose, distribute the weight of the system, and allow for positioning of the loupe and glasses to allow for not only visualization but also eye protection. Dentists with a flatter facial profile can find frame selection troublesome because the higher nasal angle may not permit the nose pads of the glasses to rest securely on the bridge of the nose.
In our goal for excellence in treatment, magnification with loupes with enhanced illumination and a dental-operating microscopes offer the ability for enhanced visualization to better perform the tasks of dental evaluation, diagnosis, and treatment.
About the Authors
David A. Williams, DDS, MPH
Clinical Assistant Professor
Department of Endodontics, Prosthodontics, and Operative Dentistry
University of Maryland School of Dentistry
Howard E. Strassler, DMD
Professor, Director of Operative Dentistry
Department of Endodontics, Prosthodontics, and Operative Dentistry
University of Maryland Dental School of Dentistry