This article explores the identity of modern dental hygiene through an examination of the history of oral hygiene. Until the 18th century, the cleansing of one’s mouth was done mainly to remove halitosis or whiten teeth. Prior to the advent of ‘dental hygiene,’ types of behavior that could be considered as acts of oral hygiene were driven by instinctive and preference-oriented demands of individuals and cultures. The view that proper dental hygiene, including the removal of dental calculus and food debris, could be helpful in preventing dental diseases arose only after the invention of the microscope and the discovery of oral microbiome. ‘Mouth Cleaning,’ which had usually been done by barbers and barber-surgeons until the 18th century, evolved into dental hygiene services, including ‘tooth brushing instruction (TBI),’ ‘gum management,’ or ‘scaling’ based on scientific evidence. Although science was instrumental in making preventive dentistry the main function of modern dental hygiene, there is a lack of research on the historical and philosophical roots of the profession of dental hygiene. This article contributes to this new line of research by providing narrative accounts of oral hygiene from a social and cultural perspective. It is hoped that this research will help to shape a new paradigm for dental hygiene.