Despite evidence for the effects of metals on neurodevelopment, the long-term effects on mental health remain unclear due to methodological limitations. Our objective was to determine the feasibility of studying metal exposure during critical neurodevelopmental periods and to explore the association between early-life metal exposure and adult schizophrenia.

We analyzed childhood-shed teeth from nine individuals with schizophrenia and five healthy controls. We investigated the association between exposure to lead (Pb2+), manganese (Mn2+), cadmium (Cd2+), copper (Cu2+), magnesium (Mg2+), and zinc (Zn2+), and schizophrenia, psychotic experiences, and intelligence quotient (IQ). We reconstructed the dose and timing of early-life metal exposures using laser ablation inductively coupled plasma mass spectrometry.

We found higher early-life Pb2+ exposure among patients with schizophrenia than controls. The differences in log Mn2+ and log Cu2+ changed relatively linearly over time to postnatal negative values. There was a positive correlation between early-life Pb2+ levels and psychotic experiences in adulthood. Moreover, we found a negative correlation between Pb2+ levels and adult IQ.

In our proof-of-concept study, using tooth-matrix biomarker that provides direct measurement of exposure in the fetus and newborn, we provide support for the role of metal exposure during critical neurodevelopmental periods in psychosis.

Intranasal teeth are uncommon. Causes include trauma, infection, anatomical malformations and genetic factors. They present mainly in children, and many are asymptomatic.

This report describes the finding of a tooth that had been displaced into the nasal cavity in a six-year-old girl. The history, clinical examination, findings and operative treatment are described.

The child presented with nasal symptoms. Examination revealed a tooth in the right nasal cavity, confirmed by a lateral cephalogram radiograph. It was extracted under general anaesthesia. At follow up, the child was asymptomatic.

This is an unusual case of a child presenting with an intranasal tooth and nasal symptoms following trauma a number of years earlier. The child underwent extraction of the tooth, and recovered well without any complications.