Closed Mouth Kissing - HIV is not casually transmitted, so kissing on the cheek is very safe. Even if the other person has the virus, your unbroken skin is a good barrier. No one has become infected from such ordinary social contact as dry kisses, hugs, and handshakes.
Open Mouth Kissing - Open-mouth kissing is considered a very low-risk activity for the transmission of HIV. However, prolonged open-mouth kissing could damage the mouth or lips and allow HIV to pass from an infected person to a partner and then enter the body through cuts or sores in the mouth. In fact a case printed in the July 11, 1997 Morbidity and Mortality Weekly Report suggested that a woman became infected with HIV from her sex partner through exposure to contaminated blood during open-mouth kissing.