What happened to the gap between David Letterman's teeth?

It’s on an extended vacation. “Gap” year from college see :¬)

Cosmetic tooth bonding with high quality polymers.

They use a chemical to etch the tooth so the bonding will adhere. Then it’s cured (hardened) with ultraviolet light. Then it is shaped and smoothed.

Think of it as a much more highly sophisticated way of doing the same thing that autobody shops do with Bondo ( minus the ultraviolet light part :)