by Leif Kullman
Report from a congress of the International Association of Dentomaxillofacial Radiology.
Recently I visited the joint 11th Congress of the International Association of Dentomaxillofacial Radiology and 3rd International Congress and Exposition on Computed Maxillofacial Imaging in Louiseville, Kentucky.
A great number of participants from all over the world (more than 50 countries) visited the congress that lasted for six days. The President for the congress had received more than 250 scientific and professional contributions to the program. There was also an exhibition in connection with the congress and many manu-facturers had taken the opportunity to show their new products including the latest digital products. These figures indicate the great interest that today is associated with Maxillofacial Radiology and Imaging, a subject that is almost as fast growing as computer technology.
To extract the most interesting contributions are therefore difficult and can also be subjectively biased of my own interest but I will anyway give it a try.
In order to embrace the congress as much as possible I have chosen to use the same subheadings as during the congress.
Perspectives on dentomaxillofacial radiology and computed maxillofacial imaging
In a paper from Japan (1) it was reported about the imaging modality for future maxillofacial diagnosis.
Many new imaging modalities are today used in maxillofacialv radiology. Computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (US) and computed radiography (CR) are all used. All of them have been developed for making diagnosis in the medical field, but today they are highly appreciated also within dentistry. However, there are also examples where, the medical field has learned of maxillofacial radiography, so each subject can learn of each other.
Other technologies will also influence us. Dramatic advances in computer technology has resulted in computer aided diagnostic imaging (CADM). With this technique we can quantify and analyse the information in a radiograph/image and facilitate the diagnosis. A great advantage is that individual physicians only can accumulate experiences for at most 30 or 40 years while CADM can do the same beyond the span of human life.
Strategies in diagnostic imaging
Computed tomography (CT) proved to be a rather popular imaging strategical method. It had been used rather often, for example to diagnose common pathological lesions in jaws, in dental implantology, to visualize pathology in the temporomandibular joint and in soft tissues as cervical lymph nodes and at different assessments before and after maxillofacial surgery. In many of these examples 3-D (three dimensional) images had been used. For example in planning a surgical operation a broad knowledge of relevant anatomy and pathology is often necessary and this can be supplied by means of 3-D images. The same images are also useful in prediction of post-operative facial appearances. Model operations can even be performed.
Technological assessments
Common reported technological news were different digital equipements, intraoral and panoramic. One of the great advantages with digital radiography and teleradiology is the ability to provide for example a general practitioner with an access to diagnostic consultations. Another advantage is the possibility to manipulate the image. If the images are going to be transmitted between computers it is important to keep the image files as small as possible. Among other things, attempts to compress images without any loss of image quality were reported.
Using teleconferencing in diagnostic imaging will in the future allow for the diagnosis and treatment of patients at remote locations from the health care provider. The same technique can be used in network between maxillofacial surgeons, radiologists and pathologists to establish diagnosis.
Radiation biology
One of the most interesting reports below this heading was a study from Gainesville, Florida, where the authors have looked upon the radiographic examination intervals and compared with the caries risk of the patients’ (2). It has earlier been found that the intervals between repeated bitewing examinations that many dentists use, not are systematically related to the oral health(caries incidence) of the patient. In order to find the high risk caries patients, where short intervals between radiographic investigations should be used, a caries risk assessment (CRA) interactive teaching program was constructed to be used together with radiographic guidelines. The most important used risk factors or parameters in this CRA method were the following:
coronal dental lesions
coronal enamel lesions
five or more decayed missing teeth
restorations within past 12 months
poor oral hygiene
poor diet
inadequate fluoride exposured
decreased salivary output
poor patient compliance
high s. mutans levels
A software tool was later used to increment a CRA risk score after that these factors had been entered in a computer. For the high risk patient the authors recommended 6 months recall while a low risk adult is recommended bitewings at baseline, 12 months and 24 months and so on. Using these principles could diminish the frequency of radiographic examinations, which have been found to vary considerable in many dental offices.
For the rest some papers about radiation doses from above all computed tomography were reported. In general this method gives a very high radiation dose compared to conventional radiographic techniques.
1.Imaging modality for maxillofacial diagnosis: A glimpse at the future.
2. Kashima, Sakurai, Kumasaka, Nakamura, Miyazu, Shinohara and Takano.
3. Automatic selection of variable radiographic examination intervals based on caries risk. Benn, Dankel, Lesser.
Next month I will tell you a little more about computer tomography (CT) investigations.
Leif Kullman
