Measuring the radiopacity of the lip and mandible.

I T HAS been a common experience among those who study dental radiographs to note the wide variation in appearance among sets of radiographs produced with standard technics. The routine x-ray examination of a group of individuals will produce some sets of radiographs which are generally dark or dense and other sets which appear quite light or thin, but the appearance of the majority of the sets will lie between the dark and light extremes. It is the purpose of this paper to report an investigation which was made to determine and predict the occurrence of the factors which cause the wide variations in the appearance of radiographs produced by conventional technics. There are manv variables involveed in the production of a radiograph. Each variable is a possible cause of the wide radiographic variations which occur among individuals.