An E1 interproximal caries is located in which part of the enamel?

• A. Inner half of enamel
• B. Outer half of enamel
• C. Dentin just below enamel
• D. At the enamel-dentin junction

Answer: (B)

In this caries-depth classification, an E1 lesion is confined to enamel and sits in the outer half of the enamel layer. That means the decay has not yet reached the inner enamel or the underlying dentin, nor has it approached the enamel–dentin junction. It remains a superficial, early enamel lesion on the proximal surface. The other depth descriptions correspond to deeper layers—inner enamel, dentin, or exactly at the junction—so they don’t fit an E1 finding.