After 31+ years, over 200 publications, and the involvement of countless faculty, staff and students, formal funding for the Iowa Fluoride Study (IFS) will end in Summer of 2023. Originally funded on September 1, 1991, as a 5-year NIH grant with a total budget of $1.3 million, the study recruited nearly 1,900 participants in Iowa hospital post-partum units from 1992-1995, and then, remarkably, followed this cohort for nearly a quarter-century, with formal subject contact ending in 2019. During that time, the IFS and the companion Iowa Bone Development Study (IBDS) were awarded about $30 million.