A medical history does not identify all “infectious patients” in the dental office. Therefore, Standard Precautions must be used when providing care to all patients. Part One of this two-part Guide discusses the history of: 1) infectious diseases and the healthcare worker; 2) the development of guidelines by the Center for Disease Control to protect both the patient and the healthcare worker; and 3) the OSHA regulations that impact the dental office. It discusses Standard Precautions for use during dental care, including aseptic procedures and personal protective barriers, as well as vaccine recommendations and management of dental waterlines. A companion Guide, “Infection Control and OSHA Update Part Two” outlines other specific infection control procedures for the dental office. It is suggested that Part One be thoroughly reviewed before reading Part Two.