Dental Dam: a cut out piece of rubberish material like the one used in condoms which is used for oral sex purposes..in other words a condom for oral sex..it prevents the transmission of sexual infections just like the condom..
Female Condom: serves the same purposes as a male condom but in this case the female inserts it in her vagina and this way the transmission of sexual infections is being prevented
..just for the record though a female condom is very hard to find since its not used as much in this country
hope this helped..=]
Its the sheet of rubber the dentist stretches across you open mouth to keep drillingsngs and other particles from going down your throat.