THE EDITOR'S CORNER

I recently-had some x-rays taken and the technician returned from the dark room with a sheepish grin, to tell me that there had been no film in the cassette for my first exposure, which would now be taken again. He reassured me that the amount of radiation was so tiny that it was insignificant. Perhaps it would be a good idea for you to turn to and read Dr. Brandt's interview with Dr. Lurie (which appears in this issue) and then come back for the rest of my remarks.

I thought back to the times when I had reassured my patients that the x-ray dose per dental film was insignificant; perhaps equivalent in a year to what might be received by walking around out-of-doors. We used to believe that there was ample room for the amount of x-radiation that an orthodontist is likely to expose his patient to in the course of orthodontic treatment. Many of us still do; and perhaps there is.

It used to be a comfort to me to believe that, although x-radiation might be cumulative, there was supposed to be a certain amount of degradation with time. Some outstanding medical and dental radiologists whom I have questioned about this are willing to believe that x-radiation is cumulative. Period. With no diminishing of the accumulated radiation with time. Another scenario might have a single exposure causing a chance triggering of malignant chromosomal transformation. Because we are not certain of the mechanism, we cannot disregard the risk factor; nor that there is general agreement among radiologists that there is risk from every exposure, which we simply have not been able to quantify.

There is a possibility that both the cumulative and single event hypotheses may be correct. In the absence of certainty, it might be reasonable to assume that the risk from x-radiation lies in both of these phenomena, to look upon each x-ray that we take on a risk/reward basis for the patient, and limit exposures to those that are necessary to provide useful information for diagnosis and treatment that cannot be obtained in other ways. Indisputably, all the preventive measures that Dr. Lurie speaks of should be used--ultra high speed film, rare earth screens, collimation, thyroid shields, high criteria for ordering and taking films, quality control to assure optimal machine and operator performance, and optimal exposure and processing procedures. A major offender in over-radiation is lack of quality control in exposure and processing of films--poor positioning, the wrong angle, the wrong side, movement, film left out of the cassette, fogged film, light struck film, worn out solutions, poor processing. Remakes should be eliminated. Duplication of exposure should be eliminated, as far as possible, through the use of double film packets for bite wings, the use of film duplication, and a library type of in/out record for films that are borrowed or loaned.

Concern about the hazards of x-radiation should bring to the surface at this time the question of whether patients and orthodontists are getting the .best information from cephalometric films. Would this not be an appropriate time to re-examine analyses that are based on Sella or other questionable points, and try to validate and use analyses that might afford better information for the exposure? Ricketts' analysis, Wits type analysis, and frontofacial analyses come to mind.

This would also be a time to research in one's own practice, the extent of the guesswork in tracing structures and points and how that relates to the actual contribution of a precise analysis based on such tracings. And, it would be an appropriate time, if one takes laminagrams, to review the films for quality and clarity and for how much guesswork goes into them, and how much the films relate to the nature and the success of TMJ treatment.

Concern over x-radiation exposure might also cause us to reevaluate the concept of early removal of third molars which do not have a significant chance for successful eruption; as determined, for example, with a Ricketts analysis of third molars. It would avoid a number of monitoring x-rays, as well as a number of visits and expense for all concerned.

The use of x-rays for orthodontic research in teaching institutions and in private offices has been drastically curtailed. Rewards that might accrue to a student, or an orthodontist, or a university, or to the specialty, or to mankind are subordinated to the risk to the patient exposed. Even with a subject willing to accept the risk for those rewards, given the present state of knowledge of the hazards of x-radiation, the burden on the operator is difficult and substantial. It recommends a research system undertaken by Rocky Mountain Data Systems in cooperation with a number of university orthodontic departments and a number of private practicing orthodontists, notably members of the Foundation for Orthodontic Research, in which clinical material from private practice is made available to graduate students for research.