Primary teeth reveal differences in chemical exposure in children with autism

Lead author Dr Lynne P. Heilbrun. (Image: Dr Lynne P. Heilbrun)

The pilot study analysed one naturally shed primary tooth from each of 38 children, including 22 diagnosed with autism and 16 typically developing children. The researchers tested for selected chemicals and screened for additional compounds not specified in advance. Sixty pesticide- and plastic-related compounds were detected in at least half of the teeth. Concentrations of 57 of these compounds were higher in the autism group, although the differences were statistically significant for only 19. Of the 60 compounds, 39 were known developmental toxicants or endocrine-disrupting compounds.

Several compounds found at significantly higher concentrations in the autism group are used in everyday consumer products, including baby bottles, food packaging, flame-retardant materials and fragrances. Benzyl benzoate, which is used in fragrances and as a food preservative, showed the largest difference in concentration between the groups. The researchers also found significantly higher concentrations of two organophosphate esters which have applications as flame retardants and plasticisers, a class of chemicals previously associated with adverse neurodevelopmental outcomes. They further noted that five of the nine compounds showing the largest differences between the two groups have been identified as substances that can migrate from baby bottles.

Primary teeth as biomarkers of environmental exposure

The study adds to findings concerning the ability of primary teeth to provide a longer-term record of chemical exposure than conventional biological samples, such as blood. According to the researchers, primary teeth can capture exposures beginning in the second trimester of pregnancy and extending through early childhood, depending on the tooth type and individual development.

“By studying naturally shed primary teeth, we can generate critical insights into environmental exposures and their potential effects on child health, ultimately helping to inform prevention and public health strategies,” lead author Dr Lynne P. Heilbrun, a research affiliate at the Kate Marmion School of Public Health at the University of Texas at San Antonio Health Science Center in the US, told Dental Tribune International.

Implications for dental research

Senior author Prof. David Gimeno Ruiz de Porras. (Image: Prof. David Gimeno Ruiz de Porras)

Other research has explored oral microbiota as biomarkers for early autism screening. Although the objectives differ, both studies illustrate the potential role of dentistry in autism-related research. According to the researchers, dental researchers could contribute their expertise in tooth development, anatomy, sample preparation and participant recruitment, complementing the work of analytical chemists, environmental health scientists, toxicologists and developmental specialists to help identify chemical exposures and investigate their potential effects on child health.

“Together, these complementary areas of expertise create a comprehensive, multidisciplinary team capable of advancing primary tooth research and its application to understanding environmental contributions to child health,” commented senior author Prof. David Gimeno Ruiz de Porras, chair of the Department of Environmental and Occupational Health at the school.

According to Prof. Gimeno Ruiz de Porras, the findings represent an important first step towards understanding early-life chemical exposures recorded in primary teeth and their possible relevance to autism. The researchers suggested that the results may reflect repeated exposure to a wider range of developmental toxicants than previously identified. Further study of the range and concentrations of chemicals retained in teeth could help clarify what primary teeth can reveal about early environmental exposure.

The study, titled “A pilot autism case-control study of pesticides and plasticizers in shed baby teeth”, was published online in the September/October 2026 issue of Neurotoxicology and Teratology.