Photographic Analysis and Diagnosis: Step One
October 1, 2009
Volume 2, Issue 3, October 2009
Page(s):
Every case requiring comprehensive functional and esthetic treatment is treated four times. The first step is to visually assess the current positions of the teeth and supporting structures relative to how they appear in the face. Understanding the concepts of complete dentistry and the functional matrix, the clinician begins each of these cases with the end in mind. Dentists can then virtually create a vision of how they would like to manipulate those structures to enhance their appearance and function. Through the use of specifically calibrated photographic views, a matrix is designed that will position these players (the teeth) relative to the curtain that encircles them: the lips. What changes seem appropriate in incisal edge position and incisal plane or reveal through various facial expressions? The second time the case is treated is through the model analysis and diagnostic wax up. Through the use of mounted study models, the clinician can study the functional relationships that currently exist and make the anticipated modifications on the stone casts to test the design. Can the desired positions and contours that have been envisioned through photographic analysis be achieved in a way that creates functional occlusal harmony? The third step is to take this dental blueprint to the patient to create prototype restorations that replicate the design matrix accomplished in wax on the diagnostic models. Only after the evaluation and approval of these prototype restorations can the dentist definitively restore an individual’s smile in a predictable way.1
Equipment
The first step in recording diagnostic-quality images is to acquire a professional grade camera that is set up for macro photography, producing resolution of a minimum of 5 megapixels. Creating quality images with some level of flexibility requires a digital single lens reflex camera (DSLR). However, without training and experience in photography, the complexity of camera systems and settings can be intimidating. Fortunately, there are many packaged systems available that are ready to go right out of the box. When pairing a lens to a DSLR camera body, it is important to be able to accommodate a minimal magnification range from 1:1 to 10:1. The images used in a practice are repetitive, therefore the camera settings, which are often provided for the dentist by the resellers, are usually limited to just a couple of simple options.
Despite the high resolutions of many of the available camera bodies, the light source is a key determinant of the quality of the image captured. Currently, there are two popular flash designs for dental camera systems: a ring flash and twin flash systems. A ring flash is an excellent lighting source for the inexperienced user: it creates consistent results, providing even lighting throughout the field. The disadvantage is that it can flatten out the depth of contours and obscure surface anatomy and color. A twin point flash requires a slightly more experienced user, but it has the advantage of capturing more surface detail, characteristics, and color, while providing good depth of contours and anatomy3 (Figure 1).4
The dentist will need a few props to help frame the subject. These include a non-distracting background for extraoral shots, and retractors and mirrors for intraoral ones. The background can be simply a blue, grey, or black cloth draped on a flat backing such as a foam board or frame, and can be held behind the patient’s head while the images are being recorded. While retractors can come in a variety of forms and shapes, usually a clear simple retractor in 2 sizes is best for photography. Opaque retractors tend to be reflective and distracting in images. Wire retractors are useful for occlusal mirror shots and tight 1:1 images. Contrasters are also effective in retracted views to accentuate incisal characteristics and inclusions, and define levels of translucency.
Finally, the dentist will need some means of viewing the images in a way that allows for adequate evaluation. Images can be displayed on a large high-definition computer screen, or even projected with a LCD or DLP projector. When the dentist has the opportunity to critically evaluate his or her own restorations—at high resolution and significant magnification—the reality, successes, and limitations of treatment can truly be appreciated.
Photographic Imaging Protocol
It is important to develop a meaningful protocol that is reproducible from patient to patient and from one point in time to another to facilitate the process of comparison, evaluation, and learning. Implementing this protocol will allow the dentist to compare images taken today to those recorded in the past (Figure 2). Each image in the sequence of views has a purpose both diagnostically and for documentation purposes, and it is critical for the dentist to understand the reasons for these views. Although additional images may be desired, there is an accepted basic template that will provide the dentist, patient, and laboratory technician with the information to achieve a successful result. Developing a disciplined protocol will facilitate consistency in results. These images should be recorded for any case requiring significant changes to tooth contour or position, and even in cases where no treatment is planned as a means of creating baseline data.
Previously, ratios that describe magnification were based upon film technology. The ratio typically compared the space that the image occupied on the actual piece of film relative to the realistic size of the object. For example, in a 2:1 ratio, the size of the actual object is twice what it would occupy on the film. However, with digital photography the size of the sensor that captures the image is significantly smaller than the standard 35 mm film size. The difference in magnification between 35 mm film and digital is approximately 1.5 X. Therefore, for this example, interpolation for a digital image of similar magnification would typically require a 3:1 setting on the lens.5
The American Academy of Cosmetic Dentistry (AACD) has a standard protocol composed of 12 views used as an assessment tool in evaluating the indications for and results of treatment: this is an excellent outline to begin documentation. These 12 views are used in a before-and-after format with the American Board of Cosmetic Dentistry (ABCD) in the evaluation process for accreditation. For the purposes of this article, images should be stored in a jpeg format, however for accreditation, images must be captured in a RAW (digital negative) format. These same views are important in documentation and diagnosis by the dentist, whether or not the case is to be used in the process of accreditation.6
In addition to the 12 views outlined by the AACD, there are additional views that are particularly informative in the diagnostic phase of treatment:7
Description of Views (Figure 3)
Conclusion
Only a few decades ago, it would have been difficult to appreciate how indispensible digital photography would become in modern dentistry: the standard for photographic documentation was limited to a film-based process that almost seems archaic from the current perspective. While previously it would take days to process images, now with digital photography the images are instantaneous, providing a powerful tool for diagnosis and treatment planning. Of all the technologies that have surfaced in dentistry in the past decade, digital photography is one of the most important tools to help dentists move their practice to the next level: to provide true excellence in patient care in today’s environment, excellent digital photographic records are a must.
References
1. Dawson PE. Functional Occlusion: From TMJ to Smile Design. St. Louis, MO: Mosby; 2007.
2. Cranham JC. Digital Dental Photography [DVD]. St. Petersburg, FL: Dawson Masters Library Vol 8; 2007.
3. McLaren EA, Terry DA. Photography in dentistry. J Calf Dental Assoc. 2001;29(10): 735-742.
4. Photomed International Web site. https://www.photomed.net. Accessed July 20, 2009.
5. Terry DA. Aesthetic and Restorative Dentistry. Stillwater, MN: Everest Publishing Media; 2009:492-493.
6. American Academy of Cosmetic Dentistry. A Guide to Accreditation Photography. https://www.aacd.com . Accessed July 20, 2009.
7. Bay View Dental Laboratory. Pretreatment/Case Planning Photo Checklist. https://www.bvdl.com/photo_communication.pdf . Accessed July 20, 2009.
About the Author
Scott Finlay, DDS, FAGD, AAACD
Faculty, Dawson Academy
Private Practice
Annapolis, Maryland
