Photography and the Operating Microscope in Dentistry
Cary Behle, DDS
Copyright 2001 Journal of the California Dental Association.
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Operating microscopes have been used in various medical surgical procedures for many decades, but they have only significantly been in use in dentistry during the past 10 years. While microscope use in dentistry started mainly in endodontics and spread rapidly to periodontics and oral surgery, restorative dentists have recently been discovering the advantages of microscope. These advantages include tremendously increased visibility and lighting, much improved ergonomics and posture, enhanced ability to utilize assistants, and, because of these factors, a significant improvement in diagnosis and treatment results. The increased visibility has also prompted the adoption of various photographic devices to the operating microscope, from traditional 35 mm photography to video and digital media, both still and motion. The purpose of this article is to discuss and demonstrate some of the photographic options that can readily be adapted to this new instrument of modern dental practice.
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Many articles have been written in dental journals discussing the benefits and techniques of the surgical or operating microscope.1-11 The goal of all dental restorative procedures is to create a bacteria-free seal, however the resolving power, or ability to distinguish images, of the unaided human eye is 0.2 mm or 200 microns.3 The generally accepted ideal margin of a restoration is about 25 microns, which is well beyond the resolving power of the human eye to see. At least 25 bacteria placed end to end could pass through an opening of that size, which is the average film thickness of most restorative cements used today (Figures 1 and 2). If a dentist can see something, he or she can better diagnose and treat it. Increased visualization, combined with much more relaxed ergonomics, makes for better treatment results, which benefit the dentist, assistant, and patient alike (Figure 3).
Photography and the Microscope
Intraoral cameras are very effective for patient education and documentation. Photography through the microscope is just as easy but with vastly improved image quality and a choice of magnifications. By using digital cameras or video along with the microscope, the dentist can have instant use of photos for patient education (Figure 4 and 5).
Dental treatment utilizing the microscope is the main reason for having one, however the dentist can also easily take photos through them as he or she works. These photos can have many applications within dental practice. They can be used to build value for dental services by showing the patient what was accomplished during the visit (Figures 6, 7 and 8). Problems or concerns can also easily be shown (Figures 9, 10 and 11). Insurance company documentation can be provided (Figures 12 and 13), and photos can be stored in a patient’s chart for reference to observe changes over time (Figures 14 and 15). In addition, a dentist can build a patient education library very easily, as well as accumulate photos for lecturing or illustrating articles. Dental assistants become much more valuable by being able to see the work in process from the same perspective as the dentist, and impressions can be examined easily and accurately at chairside (Figures 16). Information can be provided to specialists to help guide their treatment, and those specialists can be contacted by e-mail for help in diagnosis and treatment planning (Figures 17, 18 and 19). Digital cameras with computer download capability allow the use of the Internet for sending photos worldwide, and patient records and photos can be transmitted instantly. The office can e-mail before-and-after photos to patients before they have even arrived home from their appointments.
Photos through the microscope can also be used for marketing to other patients, answering questions on-line, and posting on a Web site. A series of photos can be e-mailed to a dental laboratory along with instructions typed onto an on-line lab slip (Figure 20). Full-smile images as well as shade tab comparisons and close-ups of teeth to be matched make lab communication easy and instantaneous (Figure 21). All of these benefits of photography are part of the digital revolution that is changing the technology of the dental office and the way dentists communicate with people.
Types of Cameras for the Microscope
The digital revolution is flowing throughout our lives in ways not envisioned even a few years ago. It is also rewriting the future of photography and will be the focus of this article. However, there are still many uses for film photography, such as slide images used for lecturing; but event that is changing as more and more lecturers switch to the digital format for their entire presentations. At this point, film still has an advantage over digital in the amount of detail recorded, or resolution; but this gap is closing every day. A high-end single-lens reflex camera with superb lens optics using ISO 100 film and tripod stability can capture detail equivalent to a 40-megapixel sensor.12 The top digital sensors today using either CCD (charge-coupled device) or CMOS (complementary metal-oxide sensor) technology are in the range of 3.3 to 4.2 megapixels. Therefore film resolution currently has a tenfold advantage over digital, but that higher resolution may not be necessary in dental applications. The difference would only be apparent upon extreme enlargement of the image, comparable to a 35 mm image being enlarged to poster size, 20 by 30 inches or more. There is almost no use in dentistry for this resolution, except as a reception room display. Therefore, for all practical purposes, digital images are suitable for use in the modern dental office and with the microscope.
Film-Based Cameras
The most common format and film size is 35 mm using an SLR camera body attached to a beam splitter on the microscope (Figure 22). This splits the light beam passing through toward the operator binoculars to a separate attachment for one or two cameras or a camera and assistant binoculars. Each microscope manufacturer would have to provide a proper mounting system for each type of camera. The microscope light alone is not sufficient when using ISO 100 film, so a ring flash is attached to the microscope lens, as in a standard clinical camera. Exposure is arrived at by trial and error testing for each set up. Polaroid cameras could be used if proper attachments were available, or Polaroid camera backs can be purchased to fit 35 mm camera bodies. The only advantage with Polaroid film is instant prints, which can also easily be accomplished with digital cameras and printers.
Video Cameras
Video cameras (Figure 22) use CCD or CMOS sensors. The difference is in the output, either analog to a regular TV or digital to a computer. Intraoral cameras were all initially analog since it is less expensive technology, and a television was fine for showing patients what was needed. Digital output is much greater in resolution, as are computer monitors when compared with television. With output to a computer, the resulting motion files can be stored digitally but require very large amounts of hard drive space. These files are generally now downloaded to CDs. With analog output, a simple VCR can be used. The main question that should be asked about video is: Does one need motion to demonstrate what is desired, or are still images better? Generally speaking, motion recording or live video is useful in teaching situations but not to a dental patient. Some dentists use a video monitor for visualization by the assistant rather than an assistant binocular, but this does not allow the assistant to utilize the four-handed assisting techniques properly.
Digital Still Cameras
All digital 35 mm-style still cameras also use CCD or CMOS sensors. The output is generally shown on a built-in screen or, with a plug-in wire, to a TV screen. There is constant full motion output when the camera is on, just like with a video camera. The difference is that the motion is not being recorded; only single frames are recorded and only when the "shutter" is released. Therefore, a simple digital camera can also be used for live feedback in teaching situations or for assistant visualization. The resulting still picture files are much smaller than video and easy to store in a computer. Some cameras will download directly to a computer, others load images on an electronic storage card that is then fed into a card reader to download (Figure 23). Some video cameras are also able to "capture" still images; however, because of their design, the resulting images are generally inferior to that of still-picture-only cameras. Because of the increased sensitivity of digital sensors (generally comparable to a range of ISO 100 to 1600 film), flash is not necessary; the normal fiberoptic light output of the microscope is sufficient. Another advantage of digital cameras is that white balance can be used to maximize the true color under different lighting systems. Each camera and light will require calibration to optimize the exposure. Different microscope manufacturers offer a variety of attachments for all types of cameras and would be able to assist in calibration (Figure 24).
Output from the camera can be printed out directly from the memory card to some printers or from any computer where the images are stored or networked. The two main types of printers available are the ink jet and the dye sublimate process. The ink jet is the most common computer printer. Today, the color ones that are specific for photos are almost as good as film-based prints. Different kinds of papers can be used as well as different sizes, from 3 1/2 by 5 inches up to 20 inches by up to 20 feet. Most printers will output up to 8 1/2 by 11 inches. Costs for ink jet photo printers range from $100 up to $800 or more, but very good ones can be obtained in the range of $250 to $500. Dye sublimate printers have been the main printers used with the intraoral cameras the past 10 years. Their quality is generally better, but the better ink jet models are now very close. Dye sublimate printers will range from $250 up to $5,000 or more. The main disadvantage is that almost all of the printers that cost less than $5,000 can print on only one special kind of 4-by-6-inch paper.
Learning Curve and Costs
For a dentist who has never used magnification before, it is best to start with low- to medium-powered loupes and a headlight to get some experience. Using a mouth mirror is extremely important with a microscope, and it is best to practice that with lower magnification first. The author started with 2.5x loupes and a headlight in 1986 and worked up to 4.8x and 6x loupes. The transition to a microscope in 1999 was very easy, and the device was fully integrated into the practice in a few weeks. The author recommends attending a hands-on course in the use of a microscope first, and then obtaining a mentor who uses one and can help with actual clinical cases.
Costs for a microscope will range from about $5,000 to $8,000 for an entry-level model up to deluxe models in the range of $40,000 to $50,000 with motors, balance gimbals, and zoom lenses. A very good quality microscope with assistant binoculars (recommended by the author) and a camera will be $20,000 to $30,000. Some can be mounted on a ceiling track and used in two different rooms or can be used on mobile stands, although a lack of floor space may make this inconvenient.
Conclusion
Use of the operating microscope in dentistry is growing. As more dentists realize the tremendous benefit of visualization of four, five or six different magnifications at a turn of a knob, unobstructed high-intensity lighting, relaxed upright ergonomics, and an increase in assistant utilization and speed, prices will decline and more models will become available. However, at this time, the benefits far outweigh the costs involved. Photography through the microscope is as natural as looking at the operating field. It requires almost no additional effort, and no change in position. The resulting images are superior to intraoral cameras and offer magnification unavailable with the clinical close-up cameras. The use of the resulting photographs, particularly in digital form, expand patient education and acceptance of treatment, as well as communication with laboratories and specialists.
Author
Cary Behle, DDS, is an accredited member and fellow of the American Academy of Cosmetic Dentistry and currently holds the position of chairman of fellowship, as well as board examiner for both accreditation and fellowship. He is co-founder and first president of the Southwest Academy of Cosmetic Dentistry. He established Cosmetic Dental Arts of San Diego in 1980.
References
1. Friedman MJ, Landesman HM, Microscope-assisted precision dentistry: a challenge for new knowledge. J Cal Dent Assoc 26(12):900-5, 1998.
2. Friedman MJ, Mora AF, Schmidt R, Microscope assisted precision dentistry. Compendium 20(8):723-36, 1999.
3. Carr GB, Magnification and illumination in endodontics. In, Clarks Clinical Dentistry, Vol 4. Mosby, 1998, pp 1-14.
4. Carr GB, Microscopes in endodontics. J Cal Dent Assoc 20:55-61, 1992.
5. Khayat BG, The use of magnification in endodontic therapy: the operating microscope. Pract Perio Aesth Dent 10(1):137-44, 1998.
6. Sheets CG, Paquette JM, Is magnification for you? Dent Econ Jan 2001:102-6.
7. Paquette JM, The clinical microscope: making excellence easier. Contemporary
Esthet Rest Pract Oct 1999:12-20.
8. Freidman MJ, Landesman HM, Microscope-assisted precision dentistry: advancing excellence in restorative dentistry. Contemporary Esthet Rest Dent Sept 1997:45-50.
9. Musikant BL, Cohen BI, Deutsch AS, The surgical microscope, not just for the specialist. NY State Dent J Oct 1996:33-5.
10. Michaelides PL, Use of the operating microscope in dentistry. J Cal Dent Assoc 24(6):45-50, 1996.
11. Strassler HE, Syme SE, et al, Enhanced visualization during dental practice using magnification systems. Compendium 19(6):595-610, 1998.
12. McNamara MJ, Film vs. digital, Popular Photography 65(3):50-8, 2001.
To request a printed copy of this article, please contact: Cary Behle, DDS, 2840 Fifth Ave., Suite 200, San Diego, CA 92103 or drcary@theartofdentistrysd.com.
Legends
Figure 1. The microscope is invaluable during the seating of indirect restorations, in this case a porcelain onlay on a mandibular molar. The dentist can easily see that the cement excess is continuous and equal and clean it up rapidly.
Figure 2. The final margin of the onlay seated in Figure 1 shows a properly fitted margin and good seal.
Figure 3. The dentist and assistant working through the microscope. Notice the upright posture and improved ergonomics. The assistant can see everything the dentist sees, so the dentist becomes much more efficient and therefore faster. Notice the bagging of the microscope and camera for a disinfected procedure.
Figure 4. The dentist can easily show a patient details of her teeth to determine correct treatment, or before-and-after photos at the end of an appointment, to build value in the service. A library of images can be saved for future patient education examples.
Figure 5. A full smile should be visible at the lowest magnification (2x) for diagnosis and treatment planning with the patient, as well as comparison of before-and-after photos. All the esthetic parameters can be visualized and photographed except the full-face photo.
Figure 6. In preparing tooth #14 for an all-ceramic onlay, a distal category IV crack was discovered. Magnification 12x.
Figure 7. The crack was traced out with a #330 bur to under the gingival margin. This would be very difficult to do without the operating microscope.
Figure 8. The crack was traced another 1.0 mm and then etched, primed and bonded with a fifth-generation bonding agent (Prime and Bond NT, Dentsply, Caulk), which contains acetone for the most penetration, then filled in and built up with flowable composite. The margin can now be refined for an impression.
Figure 9. A broken abutment tooth #13 under a bridge can be shown from both direct and indirect (mirror) shot. The patient can better understand the choices presented to her, and specialists can be consulted quickly via the Internet.
Figure 10. A photo at about 4x magnification showing a poorly matched implant crown and exposed implant abutment. Documentation and demonstration to the patient can be performed instantly with a digital camera mounted on the microscope and the images downloaded to a computer. Photos can be e-mailed to specialists for opinions and discussion.
Figure 11. At about 2:1 magnification ratio, the exposed implant abutment in photo #9 and tissue morphology can easily be seen.
Figure 12. An example of a small occlusal amalgam that has eventually caused multiple fractures in the remaining tooth structure. The tooth should be restored with an onlay rather than an intracoronal composite. Magnification 8x. Detail shown to patient will explain the reason for a more-extensive restoration. The photo can also be used as documentation for insurance, since this level of detail would not be visible on an X-ray.
Figure 13. Crack visible at base of lingual cusp tooth #5. Magnification 8x. Another example of a need for onlay coverage. The crack must be traced out and bonded before fracture can occur possibly subgingivally. Higher magnification would be used for this repair and preparation..
Figure 14. Cracks in a veneer can easily be seen at about 16x under the microscope. The patient can be shown something he would never be able to see with the naked eye. The resulting photo can be stored in the patient’s chart as a documentation of the situation. The patient can better make a decision about whether to "watch" this or redo the veneer.
Figure 15. A crack under an onlay is completely visible using a mirror. Decay is evident under the crack. This photo is good documentation for an insurance company because this detail would not be visible on an X-ray.
Figure 16. The dentist can easily examine his or her impression under the microscope and also send the photo to the laboratory with others via e-mail.
Figure 17. A full-smile photo taken through the microscope at 2x showing the mismatched shade and size of temporary bonded bridge pontic #8 over the implant site. This can be e-mailed to the lab for correction or done chairside. A periodontist or oral surgeon can be directed as to any tissue changes that may be necessary.
Figure 18. A full-arch-retracted photo can be used as a before or after documentation as well as for obtaining the opinions of a periodontist and/or orthodontist about the esthetic and functional improvements that can be made.
Figure 19. At about 1:1 magnification ratio (8x power), the receded tissue and exposed roots can show the patient and the periodontist exactly what is going on. Consultations with specialists can be carried out without the patient leaving the dental chair.
Figure 20. A photo of a silicone matrix preparation guide made from a laboratory wax-up of the final result desired. This helps the dentist considerably in the preparation of the teeth to achieve ideal equal thickness of porcelain. This photo can be sent to the lab to help the technician understand what the original position of the teeth was and why preps were done a certain way.
Figure 21. Shade-taking can be done as usual, and then several views of the adjacent teeth and shade tabs for comparison can be e-mailed to the laboratory. The actual color is likely not accurate, just as with all types of film, however comparisons can be made to help the technician. No film image, digital image on a computer monitor, or print done from a digital file is totally accurate with true colors seen by the eye.
Figure 22. A microscope with a 35 mm film camera and a video camera attached to the same side of a beam splitter (photo courtesy of Gary Carr, DDS).
Figure 23. A "Compact Flash" solid state memory card is loaded into a card reader for downloading into a computer.
Figure 24. A microscope with a digital still camera (Nikon Coolpix 950) attached to a beam splitter. The display can be used to compose the photo, or better, output to a television visible to both patient and doctor. Power supply is by AC adapter cord directly into the camera so no batteries are necessary (photo courtesy of Gary Carr DDS).
