A woman takes off her knickers...................?

A woman takes off her knickers and sits in the dentists chair with a leg on each arm.The dentist says 'I'm terribly sorry madam but you've made a mistake,this is the dentists not the gynaecologists,that's on the next floor' 'No mistake' she replied. 'Yesterday you fitted my husband with new dentures. Today I want you to take them out.'