Dr. Armstrong joined the College of Dentistry in 1999 after completing post-doctoral work at the college as an NIDCR Dentist-Scientist. He is a professor in the Department of Operative Dentistry, and in March 2012, he became department chair.
Dr. Armstrong's current primary teaching responsibilities include D1 operative, directorship of graduate dental materials, and lecturer in various other courses throughout the college.
Dr. Armstrong participates in the junior clinical operative clerkships.
Dr. Armstrong's primary research focus is adhesion of restorative materials to enamel and dentin. He also investigates direct tooth-colored restorative materials physical and mechanical properties.
Dr. Armstrong is a current member of the American Dental Association; the American Dental Education Association; the Academy of Operative Dentistry; the International Association for Dental Research; the Dental Materials Group of the IADR; the ADA's Council of Scientific Affairs (2007-2011); and a member and fellow of the Academy of Dental Materials.