In dental nomenclature, what does the letter I represent?

• A. Incisal edge (for anterior teeth; for posterior teeth the equivalent might be occlusal).
• B. Incisor.
• C. Internal.
• D. Interproximal.

Answer: (A)

In dental charting, I marks the incisal edge, the cutting edge of the front (anterior) teeth. This surface is what you'd see on the biting edge of incisors and canines. For back teeth, the analogous surface is the occlusal surface, not incisal, so I isn’t used there. The other options don’t fit because “incisor” names a tooth type, not a surface designation; “internal” isn’t a standard surface label in routine charting; and “interproximal” refers to the space between teeth, not a surface edge. So I accurately represents the incisal edge.