This article summarizes the concepts that are believed to cause dentinal hypersensitivity. It is no longer necessary and may not be feasible to obliterate dentinal tubules to obtain relief from the pain caused by dentinal hypersensitivity. In-office agents that obliterate the dentinal tubules may provide initial relief of pain, but they can impede the flow of potassium and nitrate ions toward the pulp and diminish the long-term beneficial effects seen with the routine use of potassium nitrate dentifrices. An in-office preparation that does not obliterate dentinal tubules, such as potassium nitrate gel, is recommended if potassium nitrate dentifrices are to be used for patient self-treatment. With the population living longer, dentists are challenged to maintain patients' dentition for a lifetime of comfort.