The dentist was called away from the dinner table to take an urgent phone call. It was Mr. Tuckerman, explaining that young Junior had gotten himself into quite a fix.

"See, he was kissing his girlfriend, and when my wife and I came back from the movies we found them stuck together."

"I'll come right over, Mr. Tuckerman," said the dentist calmly, "and don't worry about a thing. I have to unlock teenagers' braces all the time."

Mr. Tuckerman whispered, "Yes, but from an IUD?"

PS:
IUD: intrauterine device--- a device inserted and left in the uterus to prevent effective conception