---

Night shift work is known to take a toll on general health and is associated with many lifestyle-related diseases. However, few studies have investigated the influence of night shift work on oral health. Long-term disturbances of circadian rhythms can lead to marked lifestyle changes. Thus, we hypothesized that night shift workers have more oral health problems than daytime-only workers. Job stress can also contribute to oral health diseases, including periodontal disease. The mechanisms by which stress affects periodontal disease progression and wound healing can be divided into two main categories: health-impairing behavior and pathophysiological factors. Therefore, it is reasonable to hypothesize that workers who experience job stress will have predictable oral symptoms. There is an established relationship between working long hours and poor health, as evidenced by the fact that long working hours have been linked to several diseases. However, the relationship between working overtime and oral disease is lacking. This book will be useful for both workers and corporate administrators, as well as dental practitioners, as it calls attention to work-related oral health problems.

---

Koichi Yoshino, D.D.S., Ph.D.: Visiting Associate Professor, Department of Epidemiology and Public Health, Tokyo Dental College. Yoichi Ishizuka, D.D.S., Ph.D.: Senior Assistant Professor, Department of Epidemiology and Public Health, Tokyo Dental College.

---