A Snapshot of Clinical Photography

Sumeet Champaneri graduated from the University of Sheffield in 2015 and is currently a DCT in Restorative Dentistry at the Royal London Hospital.

Introduction

Clinical photography is an area within dentistry that is becoming increasingly popular amongst clinicians wanting to capture cosmetic craftsmanship to those wanting to document information to monitor dental disease such as erosion. Whatever the reason for dental photography, being able to correctly capture the area of interest using the combination of a digital single lens reflex (DSLR) camera; a macro lens; and a ringflash, will ensure reproducible photographic imaging.

Photography can be used for many reasons in dentistry, some of which include:

• Building an individual portfolio
• Promoting and marketing
• Record-keeping and medico-legal documentation
• Communication (with patient, clinicians and technicians)
• Monitoring of disease
• Shade selection
• Teaching

I was fortunate enough to encounter photography during my dental foundation year, which initiated my interest in the world of dental photography. Through multiple channels such as online media and CPD events, I was able to learn and improve my photography skills and implement this during my day-to-day practice during dental foundation training. The equipment I used included a Nikon D80 DSLR camera with a 105mm Nikon macro lens accompanied by a Sigma (EM-140DG) ringflash.

This article aims to discuss dental photography and highlight the areas necessary to ensure reproducible, high quality images are taken confidently within the dental practice setting.

Equipment

To ensure high quality images are taken every time, being able to understand the equipment and the photography settings is paramount. Understandably each clinician will have their own photography settings and preference to their equipment, but a general consensus within the dental field often relies upon the brands of Nikon or Canon.

The difference between the two brands is negligible and often comes down to price and compatibility rather than quality. However, all basic dental photography equipment requires a large financial parting as the combination of the camera body, lens and flash can cost in excess of £900.

The basic overview of the equipment that is required includes a combination of the following:

1. Camera Body

The digital single lens reflex allows the viewer to view exactly what is being seen on the lens, often referred to as TTL (through the lens). The lens along with other components of the DSLR such as the digital sensor are housed within this body¹

The rays of light pass through the lens and on to a mirrored platform. This ray of light is then reflected onto a pentagonal block of glass which directs the light into the viewfinder and directly to the viewers eyes. When the picture is taken, the mirror lifts and the shutter opens, which subsequently exposes the sensor to the rays of light, producing the image that is viewed.

2. Lens

The single most expensive part of the DSLR system and one of the key features of this type of camera is the ability to inter-change the lens. When considering the lens it is important to ensure for dental photography, a macro lens is chosen to guarantee the best quality images. In dentistry, a 105mm lens is ideal, as this allows both the clinician and the ringflash to be at a sufficient and optimal distance respectively from the patient to capture the required image.

As previously mentioned Canon and Nikon both offer lenses to excel in dental photography but there are also 'smaller' brands that can be used in either a Canon or Nikon camera body.

3. Flash

There are many flash setups for dental photography, of which the ringflash is the most common. All DSLR cameras have an internal ('on board') flash which is unfortunately not ideal for dental photography as this does not illuminate the image enough and only provides illumination in one direction. The ring-flash addresses this issue and provides illumination from all directions (360^o illumination), resulting in a well illuminated image. Unfortunately as illumination is provided from all directions, the ring-flash also eliminates any natural shadowing.

To correct this, a twin-flash setup can be used. This comprises a ring attached to the front of the lens with bilateral flash docks, which can rotate around this pivot. The twin-flash allows the natural shadowing from the smile to be captured on the image² providing a more natural and accurate photograph. The main drawback of the twin-flash is often price; amounting to almost three times the price of a ringflash set-up.

DSLR Camera Settings

During my dental foundation year, a lot of time and practice using the DSLR was carried out. This enabled a good understanding in regards to the camera equipment and its use to produce dental images to capture aspects of interest. With this I developed a table of the necessary settings that proved to result in adequate dental clinical images. 

The settings below are what I have found to result in the best dental imaging.  

From the tables above it is clear that the two variables that often need to change, dependant on the type of photograph the clinician wants to achieve, is the aperture (the amount of opening in the lens which regulates the amount of light hitting the sensor) and the magnification ratio (the image's actual size compared to the size projected on the digital sensor).

The BACD (British Academy of Cosmetic Dentistry) require 12 photographic views for their accreditation programme and to ensure high quality, reproducible and clear dental images are produced consistently, correct DSLR settings are paramount. Capturing images using defined settings also allows photographs to be compared equally over time. This is helpful when images need to be compared to monitor dental conditions such as erosion, to gather accurate information in regards to activity.

Dental Photography Consent

Consent in the dental and medical field, is an important aspect of all clinical appointments, including dental photography. Ensuring informed consent is gained for photography requires an adequate understanding by the patient as to the use of the images, the storage and the reason the image is taken. During the foundation year, informed consent was gained by firstly explaining to the patient the intended procedure, in addition to giving the patient a signed copy of their consent form.

Dental Protection advise the decision making process is recorded in the dental notes, alongside the signed consent form. With this in mind, it is paramount that adequate consent forms are within an arms reach from the dental camera, therefore ensuring patients are properly consented before photographs are taken.

Summary

Photography in dentistry will be an area that will continue to grow over the next decade as more and more clinicians become familiar with its use. The benefits are vast and include a portfolio of clinical work to be kept, allow the monitoring of dental tooth surface loss and allow shade comparison to be finalised etc. Despite this, due to the additional time needed for the consent process and conducting the standard clinical photography views, clinical photography is under-utilised.

Using the guide for the settings of the DSLR, practitioners can consistently and reliably use their DSLR camera to obtain high quality images for their intended purpose in a more efficient way, thereby minimising image errors and loss of time.

BIBLIOGRAPHY

1. I Ahmed. 2009. Digital dental photography. Part 4: choosing a camera. British Dental Journal 206, 575 - 581

2. Dental Economics: Flash systems for dental photography. Tony Soileau. Viewed 16 Nov 2016. http://www.dentaleconomics.com/articles/print/volume-95/issue-6/columns/the-world-of-digital-dentistry/flash-systems-for-dental-photography.html