Abstract
This article reviews the life story and contributions of Sumter Smith Arnim (1904-1990), a noted author, lecturer, teacher, and researcher in preventive dentistry. Following in the footsteps of Levi Spear Parmly, MD, DDS (1790-1859), and Charles C. Bass, MD (1875-1975), Arnim developed and popularized a wide range of preventive concepts and practices, especially dental plaque control via mechanical means. Today, these innovative ideas and techniques continue to have an impact on oral health research, the practice of dentistry, and the teaching of oral hygiene to dental patients. This article traces both the development of these oral health concepts and Arnim's study of dental plaque ("microcosm"), which he characterized by means of phase-contrast microscopy and cinemicrography.