[100 years of x-rays: increase in image quality of intra-oral radiographs, decrease in patient exposure].

Comparing a present-day bitewing radiograph with one of the first dental radiographs made immediately after the discovery of the X-rays, we can see how enormously the image quality of dental radiographs has improved. Besides the improved image quality, patient exposure has decreased considerably during the past 100 years. Improvement of image quality and reduction of patient exposure have been brought about by changes of X-ray equipment and radiographic films. These changes, which have led to a better image quality and a decrease of patient exposure during the past 100 years, are discussed in this article.