Background: Planning of dental support for populations serving in isolation is essential. Many programs of national or scientific interest such as U.S. Navy submarine missions, the manned space program, and research in Antarctica require long periods where dental care is not available. Submariners make an excellent study population due to their relatively large numbers, good health, excellent dental screening, and professional status. Methods: This study examines dental events occurring while underway on 240 submarine patrols from January 1, 1997 to September 30, 2000. A health events database contains medical encounter notes, demographic information, crew rosters, and medical evacuation reports. A special survey database contains information from three surveys conducted aboard 1 submarine during a 101-day submergence. The evacuation database contains medical evacuation data from the Atlantic and Pacific submarine fleets from 1991 through 1999. Results: One hundred nine initial dental emergency visits and 45 revisits were recorded during these patrols. Of these visits, 48.6% were for an emergency related to an endodontic or caries problem. The incidence rate for all dental problems was 5.0 per 100,000 person-days at sea. Smoking was significantly associated with the occurrence of a periodontal-related emergency and also with the occurrence of any dental emergency. The rate of dental emergencies per 100,000 person-days decreased over time with the rate for the first 7 days being 7.5, days 8 through 14 being 5.5, and after day 14 being 4.6. Dental problems accounted for 6.9–9.3% of all medical evacuations from submarines between 1991 and 1999. The special survey of self-reported dental problems was designed to obtain information on minor conditions that might not be recorded in the medical encounter database. Of the problems reported, 13.1% had a dental problem during the 101-day submergence, 9.8% had a canker sore, and 4.1% had a gum problem.