 The practice of using radiographs began a new era in dentistry, as dentists could finally see evidence of past dental treatments.Price spent 25 years of his career performing research on pulpless and endodontically-treated teeth, which supported the theory of focal infection, which held that systemic conditions, including complexion, intestinal disorders, and anemia could be explained by infections in the mouth.This theory held that infected teeth should be treated by dental extraction rather than root canals, to limit the risk of more general illness.