Department of Applied Oral Sciences, Center for Periodontology, The Forsyth Institute, Cambridge, MA 02142. Department of Infection and Immunity, Harvard School of Dental Medicine, Boston, MA 02115; and. Department of Anesthesiology, Perioperative and Pain Medicine, Center for Experimental Therapeutics and Reperfusion Injury, Harvard Institutes of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115. Department of Applied Oral Sciences, Center for Periodontology, The Forsyth Institute, Cambridge, MA 02142; tvandyke@forsyth.org.