Where is an E2 interproximal caries located in the enamel?

• A. Outer half of enamel
• B. At the enamel surface
• C. Inner half of enamel
• D. In the DEJ

Answer: (C)

Understanding this hinges on how proximal caries depth is described. The E denotes enamel, and the numbers indicate where the lesion sits within enamel or dentin. An E2 lesion is located inside the enamel, specifically in its inner half near the dentinoenamel junction but not yet crossing into dentin. It’s not at the enamel surface or in the outer half (which would be E1), and it hasn’t reached the DEJ or dentin. That’s why the inner half of enamel is the correct location.