Risk/benefit considerations in pedodontic radiology

The use of radiation as a diagnostic instrument, and the biological effects of irradiation have received so much scrutiny during the past decade that exposure to radiation has become a public interest concern. Most lay persons, that is nonscientists, perceive radiation exposure as possibly injurious. Knowledge of possible radiation effects has become so generally dissiminated that most lay persons appreciate that younger tissues, younger organisms, and growing organisms, seem to be more sensitive to, and to suffer more profound changes from, radiation exposure. The same lay persons also appreciate that there can be some sort of delayed effect of radiation exposure, and that the most serious delayed effect could be cancer. Scientfic study of ionizing radiation effects and the discovery of biologic injury is hardly new. Among notable early events are Major Borden’s observation of delayed epilation following skull radiographic exposure during the Spanish American War, and dentist Rawlins’ study of radiation effects on animal embryos near the turn of the century. Over the next half century, a considerable amount of information about the biologic consequences of irradiation was generated. In the early fifties, Clark, among a few other workers, was strongly critical of head and neck therapuetic irradiation for nonserious conditions in children and young adults, because of the strong possibility of causing thyroid cancer. 1 Paying no heed to such warnings, therapists, in this case better called the "irradiators," went on irradiating tonsils and adenoids. Twenty years later, there were thyroid cancer epidemics among the patients so treated. Certainly there was an important gap between those who studied the effects of irradiation and those who used radiation. Do such gaps still exist today? Do they exist in dental radiology? Do they exist in dental radiology for children? The use of X rays for diagnostic purposes in dentistry has some rather obvious good results. The common dental diseases involve tissues whose internal structures are well demonstrated upon/r~diographic examination. A dentist can thus detect and measure the extent of dental diseases where such diseases give little clinical or physical signs. In addition, the child dental patient undergoes a complex development of face, jaws, and teeth. It is well known that early detection and intervention of misdirected development can prevent substantial and difficult corrective treatments at a later age. Early detection and intervention most often depend upon radiographic examination. More generally, for any group of dental patients, good oral health is not possible without the use of X rays. How then, can there be a reconciliation between these good diagnostic goals and the hazards of achieving them? The answer is that we must find and characterize the hazards; we must examine the benefits and give them values.