Numerous factors that underlie the need for dentists are undergoing significant changes. Three factors are especially important: 1) improvements in oral health; 2) lower expenditures per patient per year, giving dentists the incentive to treat more patients to maintain incomes that justify their investment in dental education and practice; and 3) dental schools' producing new dentists at a faster rate than the growth in the population. If these trends continue, there is likely to be a dentist surplus of between 32% and 110% by 2040. A major challenge for dental schools is to adjust the production of dentists before 2040 and not wait for market forces to reduce the surplus. Whether there will be a painful market-based solution to the problem, as there was in the 1980s, or whether a more orderly path can be found is one of the key challenges of the project "Advancing Dental Education in the 21 Century," for which this article was written.