A  dentist noticed that his next patient, a little old woman, was nervous, so he decided to tell her  a little joke as he put on his  gloves.

'Do you know how they make these gloves?' he asked.

'No, I  don't,'  she replied.

'Well,' he spoofed, 'there's a building in  Canada with a big tank of latex, and workers of all hand sizes walk up to the tank, dip in their  hands, let them  dry, Then peel off the gloves and throw them into  boxes of the right size.'

She didn't crack a  smile.

'Oh, well.. I tried,' he thought.

But five minutes later, during a delicate portion of the procedure, she burst out laughing.

'What's so funny?' he asked.  

'I was just envisioning how condoms are made!'  

(Gotta  watch those little old women! Their minds are always working!)