Discussion:
It is a fallacy to categorically recommend that successful evaluation of the oral health status needs a full-mouth set of radiographs. Rather, a well organized clinical examination and questioning of the patient should precede any consideration of a radiographic examination and the number of radiographs made should be based on the previous and present dental history and clinical findings as well as age and susceptibility to dental disease. The criteria reported could be used as a guide when prescribing dental radiographs. Periapical films come in three sizes: 0 for children (22x35 mm), 1 for anterior projections (24x40 mm), and standard 2 for adults (32x41 mm). The survey results demonstrated that whether size one films are used for anterior teeth, whether canines are imaged separately, and whether bitewing radiographs are included in the "standard" full mouth x-ray survey are the main variables observed among Dental Schools. Although bisecting or paralleling techniques which are used for making periapical radiographs were not specifically surveyed, it is postulated that both methods were employed.

For anterior teeth, some schools recommend size 2 films only. There are some schools, which use size 1 films only, and, as anticipated, some schools using a combination of size 1 and 2 films. Size 1 films with a smaller width can be more easily placed in the anterior region where a dental arch is substantially narrowed or severely curved. The use of narrower films can also decrease potential distortions when imaging the anterior teeth. Size 1 films were first used in Schools within the United States, (Kodak being the manufacturer at that time in USA), and they were adopted by the rest of the world later as distribution of the product became widespread. This survey has demonstrated that some Asian Schools are not accustomed to using size 1 films. Several contact persons in these schools have never used size 1 films because films in this size are not available to them. Whether size one film can make a significant difference in the correct imaging of anterior teeth could form part of a future study.

In a fullmouth examination, from 10 to 14 and up to 16 periapical radiographs are the most frequently used combinations by Dental Schools. The major difference among these three particular formats is whether canines are imaged separately. In the ten-film format, canines are imaged with the premolars with a vertically placed size 1 or size two films. (sometimes horizontally if only short rooted canines). In the 14-film format, maxillary canines are imaged with the lateral incisors. In some "ideally shaped "arches there might not be distortions of the canines when they are imaged with lateral incisors or premolars. However, this should not be considered as a normal projection geometry. It would be helpful if there was a suitable guideline stating how the canines should be imaged according to the shape and size of dental arches. That is, a sensible less restrictive guideline.

Some Asian schools do not regularly include BW's in a full-mouth survey. It has been well documented that BW's are more accurate than periapical's in detecting proximal caries and in evaluating the status of the adjacent alveolar crest. It would be absurd to suggest though that such Schools do not use BW's regularly and have a less demand for detecting proximal caries and evaluating the status of the adjacent alveolar crest.

To the authors’ knowledge, bisecting techniques are regularly used in some schools. Theoretically, paralleling techniques should be the imaging technique of choice. For many years it has been demonstrated how these two techniques differ in the information gained and manner in which it can be used for diagnosis and treatment.

There are significant differences among Teaching and Hospital Institutions on the philosophy and format of the fullmouth examination. They vary in the type and make of films used and method of making the radiographs. How these variations affect the clinical diagnosis, clinical judgement and treatment plan need to be further studied.

Dr. Ross Macdonald (Adelaide, Australia) uses the long cone-paralleling rectangular collimated system exclusively in a busy private practice. A service demanded and appreciated by all referring clinicians. This author knows of many private radiology practices around the world, which use this technique. The authors considered that: In some cases, a lack of response indicated no solid policy on the techniques or on the size of films used.

The response rate during this study could be somewhat limited by subdued interest of colleagues within various institutions and the way in which they use the Internet services and more specifically if in fact they subscribe to or have access to the ORADLIST.

There seems to be a further need to determine the radiographic technique employed;...whether it be long cone paralleling, bisecting angle and also the types of intraoral positioning devices used. Full collimation is also a part of the techniques needing assessment.

The somewhat diverse manner (if not haphazard) in which size one or two films are used in the anterior regions has been noted and this seems to suggest the need to further investigate the merits or otherwise of this diversity

I conclude that much useful information, although seemingly simple in content, can be obtained by way of E-mail on a recognized international clinical computer network. The diversity of the methodology of fullmouth examinations requires more specific investigation, some aspects of which are critical to good clinical practice and to the safety of patients. Hopefully, it is felt that the publishing and the dissemination of information from this present study should stimulate interest, and it is reasonable to anticipate greater participation in future investigations which seem to be an obvious extension of this first attempt.