A study has been carried out investigating caries morbidity in children and changes in the macro- and microelement composition of saliva and teeth tissue depending on the degree of ambient air contamination by dust, nitrogen oxides, sulphurous gas, lead and carbon oxide. A positive correlation has been identified between dental caries morbidity and environmental factors (carbon oxide). Magnesium, silicon, iron, aluminum and copper dental content in children living in a relatively clean district was reduced. A conclusion has been made on the necessity to take into account ecological situation in the process of comprehensive prophylaxis of dental caries in children.