When you discover that the victim is wearing dentures, do not try to immediately remove them from the mouth. Prostheses help with mechanical ventilation because they support the victim's mouth and cheeks during mouth-to-mouth ventilation. If the prosthesis does not fit tightly, tilting the head back and lifting the chin will keep it in place. The prosthesis should be removed if it is so poorly secured that it can get stuck in the airway or impede the passage of air during insufflations.