Читать книгу Aesthetic Dentistry - J. Schmidseder - Страница 10

Photography

Photography is just as indispensable for aesthetic dentistry as radiography is for traditional restorative dentistry. Today, in a modern dental office, photography is routinely used for documentation, for marketing, and as a communication tool to explain different procedures to patients. If one has access to the right equipment and follows some general rules, the use of photography in dentistry is simpler now than ever before.

The first system cameras that made it possible to take intraoral photographs were introduced during the early 1960s. Until recently only the conventional single-lens reflex (SLR) cameras were available to dentists. However, today's computer technology has also penetrated into the dentist's treatment room: new digital camera systems. Today patients can be shown the state of their oral health directly on screen during treatment. In addition, the treatment goal can immediately be shown with the help of computer simulations and printouts.

24 Producing a photographic status report

In aesthetic dentistry, case documentation is very important (both before and after treatment) for patient information, communication with the laboratory, and also for general quality control.

Why take Photos?

There are various reasons for taking photos in the dental office:

—Having photographic documentation of the initial condition, the individual treatment steps, and the final result is very important.

—Dentists document their work and monitor their skills. Good recording is a part of the quality control system and offers dentists a wealth of information from, for example, the gingival condition of the patient to color differences of veneer.

—Photographs simplify communication between the dentist and the dental laboratory. Accompanying photographs greatly facilitate the work of the dental technician. The needs of both dentist and patient can be better presented and consequently the result is more satisfactory. There is hardly a bigger challenge for a dental technician than fabricating a single anterior veneer or crown. A good illustration of the situation helps the technician to succeed.

—Photographs are very helpful when used for both patient motivation and education. Photographs document what can be achieved with modern dentistry.

—“Before and after” recordings can be used as an excellent marketing tool. They make it possiblbe to demonstrate a planned treatment to the patient. It is particularly convincing when dentists presents their own treatment cases during these sessions (“J did that, and J can do that for you too!”).

—After treatment is completed, give patients “before and after” photographs that are mounted in a little album and which they can take home. A satisfied patient will recruit new patients. Excellence is and will remain the best advertisement for your practice. What, after all, is marketing? The answer is: perform well and make sure others talk about it.

—Photographs are also helpful in communicating with health providers and insurance companies. But it can also be extremely helpful to have good photographs in cases involving legal disputes.

25 Photograph of the anterior teeth

When a frontal shot of the anterior teeth is taken, the patient's lips are retracted with two cheek retractors. The photographer stands in front of the patient.

26 Photograph of posterior teeth with occluded tooth arches

The lips are here also retracted with cheek retractors. A long, slightly conical mirror makes it possible to photograph the posterior teeth with occluded mandibular and maxillary teeth.

Basics of Photography

Modern 35-mm cameras are constructed so that very limited technical knowledge is needed for their use. Most of these cameras have automatic film-speed detection, auto-focus, automatic exposure control with a synchronized flash which senses poor light conditions, and automatic film rewinding. Nevertheless, some basic photographic knowledge is indispensable.

Exposure Time and Aperture

Exposure time and aperture size restrict the amount of light to which the film is exposed. The photographer should set the size of the aperture. A small aperture (large f-number) enables a large depth of field. Therefore, the aperture should be as small as possible in macro photography. However, this necessitates a sufficiently strong light source. As long as one works within a reasonable range of magnification (1:2 to 1:1), the amount of light is usually sufficient.

Resolution

The dentist chooses the desired magnification (for example 1:2 or 1:1) and then moves the camera slowly toward the object until position and sharpness are correct. The photograph is then taken.

Lenses

For intraoral photography the dentist uses a macro lens with a focal length of 90–120 mm. Such lenses produce a 1:1 image.

Type of Film

One can select between slide or negative films. Slides can be used for lectures; prints are suitable for patient education and communicating with laboratories.

Film Speed

The film speed is given in ASA, ISO, or DIN. The recommended film speed for the case under discussion is 100 ASA.

Light Sources

Ring flashes are commonly used in intraoral photography.

27 Frontal view

When only teeth are being photographed, a magnification of 1:2 to 1:1 is suitable.

28 Lateral view using a mirror

A magnification of 1:2 (35-mm format) should be chosen.

Camera Systems

In principle, the dentist must choose between two camera systems: conventional film systems or digital storage media. Digital cameras are discussed on page 22. In the case of conventional film systems, the choice is between:

—Instant cameras (Polaroid System)

—Conventional camera systems (35-mm film), and

—APS system cameras (Advanced Photo System)

Instant Camera (Polaroid System)

In certain situation, instant cameras have their advantages, for example, if neither an intraoral camera nor a digital photo system is available and a quick photograph is needed to show a new patient the poor condition of their old restorations. If the dentist now takes a Polaroid photograph, the patient can immediately be shown the importance of the proposed treatment and the method of procedure can be explained. Polaroid pictures are also useful as a fast marketing instrument. The patient can receive “before and after” treatment photographs, which can be shown to family, friends, and colleagues. Consequently, Polaroid pictures are useful in the fast and powerful marketing of oral care.

29 Photographing the upper jaw

Retractors keep away the lips. A mirror of optimal size is placed against the lower tooth arch. The photographer stands behind the patient and photographs the patient's maxillary teeth using the mirror.

30 Photographing the lower jaw

Retractors keep the lips apart when the mandible is being photographed, too. The mirror used for photographing the upper jaw is also used here and is placed against the upper tooth arch. The photographer stands in front of the patient and indirectly photographs the tooth arch of the lower jaw using the mirror.

35-mm Photo Systems and APS System

For intraoral photography—macrophotography—SLR cameras with corresponding accessories (macrolens, flash) are indispensible for both the conventional 35-mm film format and the newer APS system.

The APS system uses a new, smaller film format (negative film) that stores all camera settings on magnetic strips. The APS film is exposed conventionally and then developed. The laboratory can later produce identical color prints by using the stored data. Furthermore, the APS system allows photos with classic, wide, and panoramic picture formats.

Because of its highly developed periphery, it is possible to transfer the pictures stored on photographic film via a video signal to a conventional TV screen for viewing. The picture can also be transferred via a digital connection to an APS player, processed by the computer, and be printed out. This could affect the dentist's decision in favor of the APS when deciding which new camera equipment to buy.

Camera Equipment

—SLR camera (APS or 35-mm film),

—Macrolens (90–120 mm focal length) that allows for a 1:1 magnification,

—Matching (TTL-attached) flash, usually ring or multiple side-flash version,

—Photographic film, for example, with standard 100 ASA speed,

—Cheek retractors and intraoral mirrors.

For intraoral photography it is important to use a camera system that allows for the use of a small aperture (usually f-32) in order to obtain maximum depth of field with the macrolens.

Examples of Conventional 35-mm Camera Systems

Two dedicated systems are especially suitable for dental close-up photography:

—Nikon Medical Nikkor (120 mm)

—Yashica Dental Eye II

Moreover, it is possible to put together a close-up system from the existing range of all major brands.

—Nikon F-601 AF or F50 with Nikon AF Micro-Nikkor 2.8/105 mm

—Minolta Dyuar 600 si classic or 500 si super with Minolta A-F Macro 2.8/100 mm

—Canon EOS 500 N or EOS 50 E with Canon EF 2.8/100 mm Macro

—Pentax MZ-5/10 or Z-70 with Pentax SMC-FA 2.8/100 mm Macro

—Sigma SA-300N/SA-5 with Sigma AF 2.8/90 mm Macro

The above-mentioned macrolenses are all original parts. For each brand, matching lenses (macrolenses at focal lengths of 90–120 mm) by companies such as Sigma, Tamron, Tonika etc. are also available that often cost half the price of the original brand names. It is difficult to decide which is the best system. It is probably still the best photographer who takes the best photographs, regardless of the system!

APS Camera Systems

The major camera manufacturers have recently introduced APS-SLR camera casings to which special APS lenses, conventional 35-mm lenses, or TTL-controlled external flashes (e.g., ring flashes) can be attached. APS systems suitable for dental close-up photography include:

—Canon EOS IX

—Nikon Pronea 600i

—Minolta Vectis S-1

31 Photograph of the upper tooth arch

A magnification of 1:3 to 1:4 is recommended.

32 Photograph of the lower tooth arch

A magnification of 1:3 to 1:4 is necessary.

Digital Camera Systems—Criteria for Selection

A new camera generation no longer records the pictures on a film but on an electronic memory chip. These pictures can be processed further on personal computers or shown on the monitor. Using a color printer such digitally recorded pictures can also be printed immediately.

Digital cameras contain a photosensitive chip (CCD sensor). This converts the picture into electric impulses (digital data). The image is stored in the memory chip, even when the camera is turned off. The image can be downloaded from the camera to the computer via a direct connection between camera and PC. Using a driver and image processing software, usually included in the purchase of such a camera, the photograph can be downloaded from the camera memory and transferred to the screen of a PC or a Macintosh, where it then can be processed. The quality of the picture depends on the pixel density of the chip, which determines whether the digitized picture is in focus or true color.

A few years ago, only professional photographers used the new technology because digital cameras were very expensive. However, relatively affordable appliances have been available for some time, whose pixel density still does not compare with that of professional cameras. The possibilities of the digital cameras are enormous. They are most suitable whereever the pictures need to be shown immediately and where there is a wish or need to process them further on the computer.

33 Professional digital camera, single lens reflex with changeable lenses, allowing wireless transmission of graphic files to the laboratory or other recipients. Additional professional Kodak cameras are the DCS 330, CDS 500, 520, 600, and 620.

34 With an appropriate printer, the images can be printed in photographic quality; here the Kodak Personal Picture Maker Kit is shown.

Resolution

The CCD sensors of a digital camera process information, which is expressed in pixels. The resolution is defined by the number of pixels per inch (ppi) or per centimeter (ppcm). The maximum picture format and the quality are determined by the pixel number.

Bit-depth

The bit-depth defines the maximum number of colors that a digital camera can capture. It not only determines the individual colors but also the hues and the shades of gray. If the gray is only divided into a few shades, an effect known as “posterization” will result.

No more than 256 (8 bits) shades of gray can be used by the usual computer programs during picture processing. Most digital cameras have a higher bit-depth. They dismantle the analogous data into 1024 (10 bits), 4096 (12 bits), or 16 384 (14 bits) steps. The computer then reduces the quantity of incoming data. Eight bits are available for each of the three primary colors, which means that it can process 16.7 million (256·256 ·256) colors.

Lenses

The quality of a picture is also determined by the quality of the lens. High-resolution, professional cameras with interchangeable lenses (e.g., Kodak of DCS 1 to DC 5, DCS 410 to DCS 460 with Canon or Nikon) are available. These modified 35-mm cameras offer a high picture quality, with, however, a concomitant large amount of image data. Only powerful computers with a large RAM can process this amount of data.

Normally, affordable digital compact cameras are sufficient for use in the dental practice. Figures 33 and 35 give an overview.

Technical Prerequisites for Digital Photography

For processing digital pictures in the dental practice the following equipment is needed:

—Camera (Figs. 34 and 36).

—PC with fast graphic card and a large RAM (preferably 64 MB or more RAM).

—Software: The most frequently used image-processing software is Adobe PhotoShop. For dental applications, a “light” version is available. However, the complexity of these programs should not be underestimated.

—Color printers: Most color printers by Canon, HP, Citizen, or Lexmark are suitable for printing the pictures immediately. The printer has become the most affordable component of the entire digital system.

35 Digital camera systems (amateur systems)

Technical specifications.

Summary

Digital technology is undoubedly the future of photography. Within a few years we will see the film as a medium for photography become a relic from the early days of photography. Digital photography offers fantastic possibilities: the pictures can be printed out immediately, text can be inserted (e.g., a treatment plan), and these pictures can be transferred using a modem.

However, the biggest advantage of processing the images directly is at the same time associated with some major risks: a digital image that has been altered cannot be distinguished from an original picture. Today, many dental presentations in the international continuing education circus are already using digital images. Hardly a printed medium still contains unmodified original pictures. The pictures are digitized when they are scanned into the computer and then they can easily be reworked using image processing software. The gingiva from one tooth site can be spliced electronically and inserted at another tooth site, tooth color can be altered ... the way has been opened for liars and cheaters, and it is appropriate to be doubtful when the results are all too perfect. Therefore, digital technology may also be a great danger for photography.

When one decides to buy a system for the practice, one should not automatically decide in favor of digital photography systems. One must be familiar with such solutions and want to solve problems associated with the computer and their programs. The existing image processing programs are still very complex. That means that digital photography can soon become frustrating. At the moment, therefore, the computer lay person should stick to conventional photography.

APS technology has some advantages over the classic 35-mm film. However, it also requires a particular film development process that is not available everywhere. If there is only a 1-hour development photo laboratory nearby, the conventional film is more advantageous. The decision to choose APS technology with its peripherals and the different formats should mostly depend on whether or not a photo laboratory close by can develop the new film system within a few days.

36 Further example of a digital camera: Fujix DS-220

This camera not only has an optical viewfinder but also an LCD display. It can be used for photography in the macro range.

It is important to develop experience of photography. A patient education album with one's own exposures can be put together. Such documentation has great power of persuasion. For example, the photos can be printed in a patient newsletter. The future of a successful dental practice lies in which treatment alternatives the practice can offer to patients. An active marketing of the performance spectrum of the practice is necessary. An important prerequisite is an extensive archive with one's own, good-quality pictures.

Dentists also can determine their own quality performance by studying the photographs they take. By regularly reviewing their own treatment cases, critical observers can assess the regular ups and downs of normal human capability and their own mastery of the art of dentistry.

Finally, dental photography is used for documentation in forensic cases. In the United States, the oversupply of lawyers has turned into the “lawyer plague” for physicians and dentists. A similar development is occuring in other countries.

Thus, to successfully integrate photography into the dental practice, the dentist and the dental assistant need to learn how to handle the camera just as well as they now handle radiographic equipment.