Dale A. Miles BA, DDS, MS, FRCD

Introduction

After 7-8 years, reading hundreds of journal articles, web pages, and textbooks to educate myself about digital imaging and its impact dental practices, I’ve arrived at the conclusion that the transition to a digital environment although somewhat intimidating, is inevitable.

It’s a digital world. As a dental practitioner you need to make this transition to digital technology in order to communicate efficiently and professionally with patients, colleagues and specialists. If you don’t, you’re just practicing "avoidance behavior".

Digital basics

To successfully enter this world you need the following things:

1. Computers
2. Networked computers
3. Practice Management software
4. Clinically useful peripheral devices that integrate easily with your practice management software
5.An understanding of digital technology, including terminology
6.Knowledge of electronic image processing (EIP)

You already own one or several computers. You probably have a patient management program. If you have several computers, you need to be able to "network" them; that is, you need to be able to link them together to share information. They may initially share the patient database as text only. This type of software allows you to make appointments, track collections, and communicate by letter to your patients. Once you add digital peripheral devices, these same computers need to share more robust data, such as pictures, x-rays and voice files.

In the digital world, this data is handled in the computer as binary data. This just means information coded by "0s" and "1s" of computers. The use of 0s and 1s allows the computer to recognize the data as a language, and allow software instructions to tell it (the computer) how you wish to treat that data. That’s all a digital image is really, a set of numbers (0s and 1s) that the computer recognizes and then proceeds to perform tasks with that data that you command it to do. As we will see later, this includes EIP.

Besides digital x-ray receptors and intraoral video cameras, there are lots of digital devices we commonly use. These include facsimile (fax) machines, digital telephones and even PDAs (Personal Data Assistants); for example, the PalmPilot^TM. A soon-to-be-introduced x-ray machine will use an interface like this to set exposure controls.

Peripheral clinical digital devices

Intraoral video cameras. These systems are now digital and wireless! A new camera system (the DP-6 and DP-15) from RF Systems Lab of Nagano, Japan even comes with a wireless LCD, wristwatch display device. Figure 1 shows the DP-6 camera. This system is small, portable, lightweight and inexpensive.

Figure 1

Digital x-ray systems. As of this writing, there are 16 intraoral digital x-ray systems available for your dental office. In a future article I divide these systems into CCD, CMOS, CID and PSP categories to avoid confusion (see Dental Products Report in November). They are not all the same. In addition to these intraoral systems, there are several digital panoramic machines in the marketplace which use digital technology for image capture information. Instrumentarium, Belmont, Planmeca, Sirona, and TREXtrophy currently employ CCD sensor systems for panoramic image acquisition. Digital panoramic images are incredible. Recently, in Concepts magazine (Burkhart Dental, October, 2000) I outlined the advantages of these full featured, digital panoramic systems. These machines acquire the image electronically. That article appears on this site with their permission. Figure 2 shows another type of digital panoramic image produced by scanning a digital photographic print of a conventional panoramic film printed on Kodak’s new DMI 1200 printer. This would obviously be an indirect digital image. In this case it is even a 3^rd generation image. Yet it’s quality is outstanding.

Figure 2

Indirect panoramic image scanned as a print.

(Image courtesy of Mr. William Altvater, Eastman Kodak Company, Health Imaging Division)

Other digital devices. The digital periodontal probe, digital blood pressure cuffs, digital thermometers and voice-activated charting software are all available for the dental office. Your transition to digital technology is inevitable!

Pixel, voxel, image reversal, image processing, histogram, dynamic range, bit depth, CCD, CMOS, CID, storage phosphor, the list of terms you need to be familiar with is endless when it comes to mastering and understanding digital technology. That is why I have included a glossary with each of these articles for you to refer to when you read. Really the CCD (charge-coupled device), the CID (charge induction device) and CMOS (complimentary metal oxide semiconductor) are all variants of solid-state x-ray detectors. These devices also can detect light photons, and so they are used in cameras, video cameras and other imaging devices. A CMOS chip is already in every computer in the world. Now they've managed to put an image receptor portion on the same chip! Figure 3 diagrams the CMOS "chip" and receptor, sometime termed a "camera on a chip".

Figure 3

A CMOS "chip"

Sensors or receptors in digital imaging are really just solid state devices; silicon chips like those in computers. In Figure 4, modified from one of my textbooks^1., I have diagrammed such a detector. This diagram will also appear in the DPR article in November or December.

Please look for the series of articles in Dental Products Report for a more detailed description of digital receptor.

X-ray film, once processed in chemicals, is static. It is now just a display device. The only way to gain additional information from the image is through EIP. Yes, even this x-ray film can be processed electronically if it can be scanned and stored in a digital format. Of course film digitization by scanning is a more cumbersome, time consuming process. However dentists may wish to do this for image comparison, improving image quality or archiving the image content more durably. The digital image, whether directly acquired by a CCD or other solid state detector, or scanned is displayed on a computer monitor for EIP. The image can be subjected to all kinds of image processing steps or tools to extract more information to make better clinical decisions. This is what medical radiologists have done for years. Now we can do it in dentistry. We can improve our interpretation of disease processes, by selecting tools to enhance a feature about the disease to make it more obvious. This is NOT image manipulation. It is EIP. It is done to help the dentist manage the patient’s problem with more certainty.

Figure 5 shows how I enhanced the carious lesions in these periapical x-ray images to make them more "visible".

Figure 5

Educating yourself about digital imaging takes time and patience. The technique of acquiring the image is no different than with conventional x-ray technique. The real challenge is to take the time to understand the elements necessary to make the transition, computers, networking, terminology, and electronic image processing (EIP). Hopefully the articles on this site will make your transition easier and more rewarding.