Dental Photography for Photographers
prepared by:
Michael Peres
School of Photographic Arts & Sciences
70 Lomb Memorial Drive
Rochester, New York 14623
716 - 475 -2775

Dental photography is not a new field and is considered to be a sub-specialty of clinical/medical photography. Dental photographs can include external facial views as well as intra-oral views for practitioners of all dental specialties as well as oral surgeons. Dental pictures are typically taken of the teeth and/or oral environment to illustrate dental disease, malformations, soft tissue, the development of the oral cavity as well as other aspects of mandibular and maxillofacial formations.

Photography has proven itself to be a valuable aid to all aspects of medicine including dentistry. Comparative pictures are often generated to illustrate the procedures over time or the portrayal of a condition using various spectrums. This might include visible, infra-red and ultra-violet which can illustrate aspects of a condition not visible by other means.

Dental pictures are currently used by dentists for monitoring treatment plans, teaching, publishing, and/or research as it pertains to their work. Additionally the overall healthcare environment has also changed and thus dental pictures are being used for other applications. Marketing of dental products and dental services are two of these newer applications as well as documenting for legal (malpractice) cases.

Dental Terminology
Anterior - front
Posterior - rear
Palatal - roof of mouth
Lingual - tongue
Gingival - gum
Buccal - cheek
Occlusal - biting surface of teeth
Occluded - biting surface together
Mandibular - lower jaw
Maxillary - upper jaw
Amalgam - filling material
Calculus - hard deposit formed on tooth
Enamel - composition of tooth

Producing pictures for dentistry and its sub-specialties can be straight forward when external views are required. No special equipment or approaches need to be used and many of the pictures taken are commensurate with other clinical recording sequences. A typical series might include a full facial anterior view as well as left and right lateral facial views. Depending on the size of the dental facility, dental photography may be done by a trained dental photographer or by the dentist with limited experience in photography itself.

Intra-oral procedures are a bit more complicated and require substantially more equipment and expertise. The views most often produced include a full view of the anterior teeth in occlusion. Additional views might include the palatal and lingual surfaces, the left buccal and right buccal views as well as possibly the left and right lingual views. Shooting protocols often are standardized by the dentist or department where the photography is being done. Because intra-oral views are not possible with normal camera systems, special lenses and mirrors are required.

Because of the need for photography to be done on-site, most camera systems are kept chair side or in close proximity to the clinic. The camera system could include(in most instances), a 35mm single lens reflex system(SLR) camera, a lens capable of doing close-up photography, an electronic flash, mirrors and retractors. The specific brand of camera is not important, but rather that the camera system is capable of some of the following functions as well as being simple to operate
Most dental photography is done with 35mm SLR camera systems, although some work is also accomplished with Polaroid cameras and of course digital cameras. The SLR camera used in dental photography can be broken down into its body and lens. The camera body, can influence the ease in which good results of dental photography can be obtained. by offering the photographer additional features such as auto-exposure and auto advance. Cameras that are manual will function perfectly adequately, however cameras with auto exposure allow for more concentration to placed on the patient and not photography.
The use of a SLR is valuable for several reasons. The are a variety of films to choose from, they are compact and easy to use, but probably most importantly is they can utilize interchangeable lenses. The lens is one of the more important elements for good dental photography. Obtaining the highest quality result in dental photography is facilitated with a close-up lens that is inscribed with reproduction numbers. Typical recording ratios for the above mentioned views might include 1:2, or half life size up through 1:7 or one-seventh life size. Good quality lenses come inscribed with these numbers allowing for standardization of views, magnifications and exposure information. For magnifications greater than 1:2, close-up lenses or extension tubes will be needed. This becomes important when standardizing is important.

Intra-oral views require much depth of field to insure the entire dentition is maintained in sharp focus. Lenses for dental photography should be capable of minimum apertures of at least f22 for best results. Lenses also should be chosen for working distance considerations. The shorter the focal length, the closer the lens to the patient, consequently, lenses of approximately 100mm focal work very well for providing a large enough image size without invasion of the patients space. Although auto focus lenses work well for some situations, intra-oral views may fool the focusing systems to produce less than adequate results.
To assist with intra-oral views special mirrors need to be used. Mirrors for dental photography can be either polished metal or front surface glass mirrors. Either will produce satisfactory results. Mirrors come in three shapes for various applications, palatal, buccal and lingual. Because of a wide variety of applications, mirrors also come in adult and pediatric sizes. To facilitate the recording of the appropriate field with mirrors, proper retraction of the lip must be accomplished with unobtrusive retractors. Because of reflections, plastic proves much more desirable than metal.

Mirrors & retractors:

Evaporated Metal Films
701 Spencer Road
Ithaca, NY 14850
1 - 607 - 272 - 3320

Lip & Cheek Retractors:
GM Orthodontics
619 E Germantown Pike
Norristown, PA 19401
1 - 800 - 233 - 4724

To insure maximum quality and fidelity in the recording of dental pictures, electronic flash is imperative. Use of ambient, daylight or overhead fluorescent lights will produce less than satisfactory results even with high speed emulsions because of poor color rendition. Electronic flash may be manual in its output, which then would require calibration of its output at various repro-ratios for proper exposure, or the flash may be automatic. Automatic or Auto-thyristor type flashes may also produce unsatisfactory exposures due to reflection of the majority of illumination coming from the face and not the interior of the mouth. Through-the-lens(TTL) metering systems provide the easiest and most accurate results of intra-oral views.

Electronic flash systems can be acquired in either ring light or point light configuration. The ring light is very easy to use and provides shadowless illumination for deep cavity views. The light is uniform and very low in contrast. Point lights, which are small electronic flash units of approximately guide number 80, provide very satisfactory results as well. This type of light will produce some shadowing and is of higher contrast than a ring light which may be desirable for illustrating various anomalies. Placement of this light should be evaluated for where the cheek/lip will cast its shadow as to not interfere with the dentition in the far regions of the mouth.

Because the mirror plays a critical role in the picture making process, certain considerations are important for the optimal result. The mirror most probably will be stored at room temperature and to achieve good intra-oral pictures should be brought up to body temperature. This will prevent fogging when it is placed in the mouth. The mirror must be cleaned and dried prior to each picture so none of the water marks interfere with visibility. Because the mirrors are glass or polished metal, they are easily scratched and consequently great care should be taken in cleaning and storage.

To facilitate proper recording, all photographs should be made on axis. Thus all pictures will portray the various elements in the spatial relationship that is most effective with minimal distortion

- Clinics of North American Dentistry, C. Freehe
- Biomedical Photography, J.P. Vetter