March 3, 2020
by Fred Peck, DDS, FAACD
As the saying goes, “do you know what the best camera is?” It’s the one that you have with you. Photography usage in dentistry is an essential part of proper documentation of a patient’s current condition. Just as a dentist needs radiographs for a proper diagnosis of health and disease, photography can also help with analysis and documentation of oral health.1
Photography helps to analyze oral conditions, long after the patient has left the office. Often comprehensive treatment plans are completed after an examination. Photography can record gingival conditions including the color of the tissue. Is this tissue pink and stippled or red and inflamed? Is plaque and food debris present? Is gingival recession present, what does the root exposure look like, what is the position of the teeth that may contribute to the condition? Words and X-rays just cannot completely describe current conditions.
Additional information obtained from photography include documentation of chips, occlusal wear on a global basis, erosion and discolorations, all of which can be compared to future photographs to evaluate changes. This author believes that every new patient exam should include a series of photographs.
There are many types of cameras that can be used for dental photography, in addition to intra-oral cameras. This article will discuss extra oral camera usage. There are essential photographs to be taken on the patient.2 In all frontal photos, the patient must be aligned level to the horizon. Any tilting of the patient’s head will render an inaccurate photograph. (Figs. 1 & 2). One would not be able to tell if a midline is canted or if the arch is level or not. Photography also allows for integration into the digital aspects of dentistry, by helping to align the teeth in the face with a digital scan.3 This can be accomplished with the Panadent Kois Dento-Facial Analyzer, a LazrTrak and Facial Reference Glasses (Fig. 3).
All images should be taken before the teeth have time to dehydrate.4 As a tooth is exposed to air without the benefit of saliva, the dehydration that occurs removes color details, and color matching techniques will be useless. There are many image views that can be taken, but the clinician should determine the series that works best for documentation, and proposed treatments and become proficient with obtaining those pictures.5
A full-face image with the patient smiling is the first picture taken. The background should be non-distracting and not taken in the operatory with equipment showing. A blue background, which is often referred to as a muslin fabric background is best, which can be hung anywhere in the office or held behind the patient (Figs. 1 & 2). The blue muslin cloth can be framed, hung loose on the wall or hand-held. Additional photos with the background can include a side full face profile, front face profile smile with teeth apart and another with lips at rest (Fig. 4).
The camera that most of us have is our cell phone with a built-in camera. This camera can take the full-face images and some of the smile and retracted views. Smile and retracted views are further away from the face and lighting is easier with natural interior light or LED lights mounted near the camera. Close-up images may require additional iPhone/Android camera accessories. These types of photos are helpful but are harder to reproduce in the same magnification and the same position across all patients and with future images on the same patient, as will be discussed. The image file format of this type of camera photograph is a .jpeg. These iPhone photos can be saved to an external flash drive, such as an iXpand drive or to a secure version of Dropbox. This method keeps the photos off the phone storage, which may not be secure.
As we get into higher quality cameras, the photo consistency increases and settings on the camera can be more specific for dental/medical photography. As with increased quality of the camera and image, this comes at a higher cost. The next level of camera would be a point and shoot camera with a fixed lens. These are off the shelf cameras modified by value added resellers to add the close-up features and flash options. They have close-up filters and sometimes a ring flash. A ring flash attached to the front of the lens is used to illuminate the field of view of the lens, in this case the mouth. The image file format of this type of camera is a .jpeg and sometimes a RAW image, discussed later.
The highest quality level of cameras for dental usage are DSLR (digital single lens reflex) cameras. These are digital cameras with removable lenses. The lenses are specific for portrait and close-up or macro photography. The two most popular brands of camera for medical/dental photography are Canon and Nikon. There are various levels of cameras in this category. Entry level DSLR cameras have a smaller or cropped sensor. The image quality is excellent, but the user must compensate the 1.5 magnification with setting the lens correctly. The highest quality level of cameras are DSLRs with a full frame sensor. This cost is the highest, but so is the image quality. Image file format for a DSLR camera can be .jpeg or RAW image. Prior to details of using a DSLR camera, let us discuss image file types. A .jpeg image can be edited and changed without the viewer of the image easily detecting this manipulation. A RAW image is the raw image data without any processing. A RAW file cannot be changed and would qualify as a secure file for dental record keeping, as the file cannot be altered and still be saved as a RAW file. Any changes are saved in a modified format and not the original format in which it was taken. RAW files take up a significant amount of storage on a computer, but hard drive storage is inexpensive. In the American Academy of Cosmetic Dentistry accreditation process, RAW images must be included to prevent any fraudulently altered images.
This author keeps his images on a separate computer, that is backed up online daily, automatically. The images are not stored in any software program but in unique individual folders under a master patient folder with sub folders in patient names and dated. Keeping them outside any software program, will prevent any size compression of the image and will be unaffected by software algorithms. These folders can be kept in a file structure as this on both a PC and Mac format. Most importantly, if the images are kept only in some type of software program and the company goes out of business, you may not be able to recover your images. This has happened in the dental field and many either lost images or had to pay additional money to recover their own photos.
Our attention to capturing images will be discussed on a DSLR camera.6 Using a macro lens, the magnification is a part of the settings on the lens and can be pre-set. A 1:1 image ratio corresponds to old slide film, where if you set the lens to 1:1, the image printed on the slide was actual size (Fig. 5). Today, we look at a 1:1 ratio to capture for example on the upper arch, cuspid to cuspid (Fig. 6). This 1:1 would be on a full frame sensor camera. Taking the same image on the same patient would be consistent over time. One would see the exact same details on these photos at any time in the future, hence very consistent results. On a cropped sensor camera, also known as APS-C, the ratio would be 1:1.5. The magnification to capture a smile, or full retracted view would be 1:2 on full frame and 1:3 on APS-C sensor. The full face is taken at 1:10 or as close to 1:15 on an APS-C camera if 1:15 is not marked. The focus is set to automatic for the full-face image and manual focus for all other images. The full-face image can be taken in a dental photo studio which can be created anywhere in a dental office, including a hallway or any room that has a little excess space (Fig. 7).
When taking a photograph, there are some other settings to consider. This relates to aperture settings, shutter speed and ISO. Aperture is the amount of opening of the lens diaphragm that lets light in. The higher the aperture setting the less light that comes through, the better the focus is for the entire photo. At an aperture of 36, everything is in focus. The shutter speed is how long the shutter is open. A fast shutter speed, or higher number lets less light through. There is a balance between how far open the aperture is with a fast-enough shutter speed to allow a clear picture without camera movement. ISO refers to the sensitivity of the image sensor. A lower ISO means the camera is less sensitive to light but allows for a clearer photo with a finer image. Higher ISO allows for increased sensor sensitivity, but the image loses clarity, and can have “digital noise” or appear grainy. The last component is the amount of light on the subject from the flash.
This author uses an ISO of between 200-250, with a Nikon D800, at the present time. Shutter speed is between 1/60 second to 1/125 second. The aperture is F 11 for a full-face image and F 36 for the close-up images. The lips are retracted with lip and cheek retractors (Figs. 8 & 9). The flash is set to sync with the camera, set to TTL (through-the-lens) where the camera determines the amount of light needed. Taking these settings into account, the best way to determine what is best for your camera is to use a model as a subject, document the settings and determine what works best for your camera, in your office with your lighting.
The minimum number of photos this author takes on a new patient is 17. Full face frontal and side at 1:10, Smile: front, right, left at 1:2 (Figs. 10-12). Retracted teeth apart front, right, left and teeth together front, right, left, at 1:2. Upper arch at 1:1 front, right, left, lower anteriors at 1:1. Full upper and full lower arch at 1:2 (Figs. 13 & 14). Often there are additional photos taken as needed.
Setting the Camera for Colour Communication
Colour can be standardized utilizing the White Balance feature on a DSLR camera. White balance (WB) is the process of removing unrealistic color casts so that objects, which appear white in person are rendered white in your phaoto. Proper camera white balance must consider the “colour temperature” of a light source, which refers to the relative warmth or coolness of white light. Different white balance settings show as different colour tones. The proper white balance setting would be a custom white balance.
Proper value, the amount of lightness vs darkness, can also be evaluated using black and white images.7 Colour and value can be evaluated using a cross- polarization filter. Polar Eyes from Photomed, Inc. are an example of these filters that can be adapted to both Nikon and Canon DSLRs. These filters eliminate unwanted reflections on the teeth that are caused by the flash. These specular highlights can obscure details in the teeth and cause problems when communicating with the lab (Figs. 15 & 16).
The advanced dentist should be taking photographs on every patient and for a variety of uses. In addition to them being part of the legal chart, photography increases effective communication with the lab technician, dental specialists and the patient. Only the basics of dental photography have been addressed in this discussion, but further education is necessary to increase one’s skill in this essential component of data accumulation, to produce a more rewarding result to the dentist for the benefit of the patient.
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About the Author
Fred Peck, is an Accredited Fellow of the American Academy of Cosmetic Dentistry and a Nikon Professional as a member of Nikon Professional Services. In addition, he lectures in the US and Canada on esthetic dentistry, lab communication and photography. He maintains a full-time private practice in suburban Cincinnati, OH. He states no conflict of interest related to this article.