Therapeutic gamma radiation: effects on microhardness and structure of current composite restorative materials.

Oral cancer patients, receiving gamma radiation as primary or supplementary treatment, commonly have a variety of dental restorations including composite resins. Any interactive effects between the incident therapeutic beam and such materials might be of clinical significance if properties of these materials are adversely affected. In this investigation the effects of gamma radiation at three therapeutic dosage levels on microhardness of three current composite restorative materials were determined. It was also the objective of this study to detect any possible alterations in the chemical structure of these materials after gamma radiation using infrared spectroscopy. The results showed, in general, a significant increase in mean microhardness values (P