UCSF

Teeth, with their remarkable preservation in the fossil record, have long been instrumental in uncovering insights into human history. Similar to the way tree rings record growth patterns, dental tissues capture and preserve evidence of environmental disruptions at the time of their formation. Deciduous (primary) teeth, forming from Week 6 in utero into early childhood, capture prenatal and postnatal time windows that overlap with brain and nervous system development. Unlike bone or neural tissues, primary teeth do not actively remodel and thus provide a lasting and faithful record of an individual's early life, making them potential predictors neurodevelopmental outcomes. However, further research is needed to fully understand how primary teeth develop in altered environments before they may be used as diagnostic tools of neurodevelopment. Given strong evidence linking early life stress to neurodevelopmental and mental health conditions, we investigated whether environmental stress leave imprints in primary teeth. Microcomputed tomographic (microCT) analysis of kindergarten children’s lower central incisor revealed measurable changes in the enamel, dentin-pulp complex, and eruption patterns in children with elevated cortisol levels. Furthermore, our empirical investigations in a mouse model of Early Life Adversity (ELA) showed that stressed pups exhibited distinct changes in tooth enamel mineralization and gene expression of key regulatory proteins (Amelx, Enam, Dlx3, Igfbp2, Per1, Nrd1). Identifying and understanding how these early life stress biomarkers are produced, is a crucial step forward towards using primary teeth as diagnostic tools for children at risk of stress-related mental health conditions.