Why a Dentist Pulled His Own Tooth on Laughing Gas

Hartford, 1844: at a laughing-gas stage show, a volunteer gashes his leg and feels nothing. A young dentist in the audience notices — and the next day he has one of his own wisdom teeth pulled under the gas. Why did his big demonstration end in shouts of "Humbug!", who won with ether instead, and why is laughing gas (nitrous oxide) still in the dental chair today? Plus: the surgeon who invented the dental nerve block — and became addicted to cocaine — and how local anaesthetics (anesthetics) really switch off pain, in 3D.

Every Then vs Now episode ends with what a surgeon would do today.