The Dentist is one of those pieces of comedic glory that only comes around once a generation.
His goal in life was to destroy poor Harvey Korman in front of that live audience. Right at the 6:12 mark you see just start to fall apart.
I LIVED to watch Tim Conway and Harvey Korman crack each other up each week. I would be hard pressed to come up with a favorite skit but the dentist is up there, along with the GWTW spoof.