A model for dentinal caries progression by digital subtraction radiography.

Extracted teeth with preexisting carious lesions were incubated in vitro at 37 degrees C in an artificial saliva buffer. Four teeth were exposed to buffer alone, four to buffer containing 5% glucose, and four to buffer containing 5% sucrose. Time-lapse radiographs were made of the carious lesions using an orienting device that fixed the position of the tooth, x-ray film, and x-ray tube collimator. The radiographs were analyzed over a period of 8 weeks using digital subtraction radiography. The subtracted images revealed that three of the four teeth incubated in saliva alone showed an increase in radiodensity (remineralization) at the depths of the lesion; one tooth showed no detectable change. Three of the four teeth incubated in the presence of 5% glucose showed increased radiolucency (demineralization); one showed no detectable change. The four teeth incubated in the presence of 5% sucrose exhibited results similar to those teeth incubated in 5% glucose.