In North America, all dental schools have adopted some form of community-based dental education (CBDE) or service-learning, but little is known about the areas being researched and reported in published studies. The aim of this study was to conduct a scoping review to determine what areas of research had been conducted to determine the effects of CBDE on dental students' readiness to treat populations that are underserved. A systematic search of articles published in English or French since 2000 was performed on July 29, 2015, and combined quantitative and qualitative synthesis of data was conducted. Of the 32 studies evaluated, 23 (72%) were quantitative, seven (22%) were qualitative, and two were multi-method. The majority (66%) used self-report methods, most frequently surveys. Participants in 50% of the studies were fourth-year dental students; the others assessed third- and fourth-year (13%), first- and second-year (6%), and first-year (13%) students. Dentists were the participants in three studies (9%), with dentists and students in one study (3%). Either the types of populations receiving care were unspecified or four or more groups were pooled together in 25 studies (78%), while two focused on children, one on rural populations, one on elderly populations, two on persons with special health care needs, and one on low-income populations. The study areas were wide-ranging, but generally fell into three categories: student performance (37.5%), teaching approaches and evaluation methods (37.5%), and perceptions of CBDE (25%). This review identified many research gaps for determining whether students are prepared to treat populations that are underserved. The disparate nature of CBDE research demonstrates a compelling argument for determining elements that define student readiness to care for patients who are underserved and for research that includes the voices of patients, curriculum development, and more comprehensive and rigorous evaluation methodologies.