In their investigation of chemical exposure in dental personnel, Lindbohm et al1 conclude by saying that there is a weak association between exposure to chemical agents and an increased frequency of spontaneous abortion. Based on their data, the authors propose in the Policy implications section that “In general, there is no need to restrict work in dental clinics during pregnancy”. We would like to express our concerns about their statement before these results reach public health policy.

In this survey, the most important methodological limitation was the complete absence of measures of …