[The x-ray opacity of tooth-coloring inlay materials and composite cements]

For a proper radiographic diagnosis of secondary caries and interproximal overhangs or undercuts, tooth colored inlays and their appropriate luting agents have to be radiopaque. With the help of a spectrophotometer the radiopacity of 1 mm thick samples made of enamel, dentin, seven tooth colored inlay materials and seven composite cements was quantitated and related to 99.5% pure aluminum. The mean radiopacity values of three inlays (two of them significantly, p less than 0.05) and of three composite cements (one of them significantly, p less than 0.05) were lower than enamel. All other materials tested exhibited a higher radiopacity than enamel. A radiopacity value of 1 mm thick samples greater than 2.5 mm of 99.5% pure aluminum is advocated by the authors. Four of the materials tested fulfilled this requirement.