Are dental dams a necessary part of oral sex?
Great question! Dental dams are a great tool to help protect yourself and your partner from common infections, especially herpes and hpv. Dental dams also help protect against urinary tract infections and bacterial vaginosis. Herpes and HPV are both infections that can often be managed, but can also stay with you for the rest of your life and cause more dangerous complications. Some rare strands of HPV can lead to throat cancer, for example.
Do you, or anyone you know, get cold sores around your mouth? Those are a form of herpes, and if that cold sore touches another person's mouth or genitalia, herpes can easily be transmitted. Herpes is most contagious during and right before an outbreak, although it can be passed even if there is no sign of the blisters! Dental dams are the absolute best way to prevent the spread of herpes!
The bottom line is that dental dams protect you from many common infections and sex is so much more fun if you don't have to worry about those things! Incorporating consent into all aspects of your sex life is important, and how you engage in safer sex is no exception. Therefore if you choose not to use a dental dam, make sure this is an informed consentual decision for all parties involved. And of course, if you don't use dental dams, make sure you get regularly tested by your doctor!
For more information:
http://www.scarleteen.com/article/bodies/all_the_barriers_all_the_time (scroll down to read about dental dams)