The dentin is not as radiopaque as enamel. Which statement is true?

The dentin is not as radiopaque as enamel. Which statement is true?

• A. Dentin is more radiopaque than enamel
• B. Dentin is less radiopaque than enamel
• C. Enamel is less radiopaque than dentin
• D. Dentin is invisible on radiographs

Answer: (B)

The concept being tested is how radiopacity differs between enamel and dentin. Enamel has the highest mineral content of any tooth tissue, about 96%, so it attenuates X-rays the most and appears very bright on radiographs. Dentin has a substantial mineral content but less than enamel, with more organic material and water, so it attenuates X-rays less and appears a lighter shade than enamel. Because of this difference in mineral density, dentin is less radiopaque than enamel. It’s not invisible on radiographs; it simply appears less white than enamel and more radiopaque than the pulp. Cementum, by the way, has even less mineral content than dentin and is typically less radiopaque than dentin.

The concept being tested is how radiopacity differs between enamel and dentin. Enamel has the highest mineral content of any tooth tissue, about 96%, so it attenuates X-rays the most and appears very bright on radiographs. Dentin has a substantial mineral content but less than enamel, with more organic material and water, so it attenuates X-rays less and appears a lighter shade than enamel. Because of this difference in mineral density, dentin is less radiopaque than enamel. It’s not invisible on radiographs; it simply appears less white than enamel and more radiopaque than the pulp. Cementum, by the way, has even less mineral content than dentin and is typically less radiopaque than dentin.