Hard tooth tissue (enamel, dentin, and root cement) consists of several minerals, with calcium being the main macro-mineral. Minerals of physiologic importance as well as toxic metals can bioaccumulate in the calcified tissues, i.e., teeth and bone tissues [1]. Hard tooth tissues are distinguished by their limited ability to release accumulated elements into systemic fluids. Therefore, teeth provide ideal biological samples for the evaluation of long-term environmental exposure to toxic metals. The mineral and metal contents of teeth reflect their overall content in the whole body [2, 3]. Tooth samples have been used to evaluate the environmental exposure of a body to lead and cadmium [4, 5]. In the present study, we examined the content of these metals in the deciduous teeth. These teeth are readily available and their analysis can reflect exposure to toxic metals from the time that odontogenesis begins in the fetal period to when the tooth is lost. However, toxic metals that accumulate in teeth remain in a dynamic balance with normal tooth components. For example, heavy metals can replace calcium in hydroxyapatite crystals which are basic structural units of calcified tissues. Therefore, evaluation of cadmium and lead levels in the tooth hard tissues should be based not only on absolute content of these metals but also on the ratio of these metals to calcium. Such ratios are more representative of the relative changes in the levels of accumulated metals [6, 7]. While a variety of factors may influence the content of heavy metals in hard tooth tissues, our research focused on systemic diseases that require long-term treatment with restrictive diets. In pediatric patients, such diseases include celiac disease and food allergy conditions [8–10]. The long term implementation of restrictive diets has been linked to mineral deficiency in children as well as quantitative or/and qualitative changes in the mineral content of bone and hard tooth tissue. These alterations may result in increased accumulation of toxic metals, such as lead, cadmium, strontium, mercury, and arsenic in the body [11, 12]. The aim of the present study is to evaluate the levels of selected toxic metals, cadmium and lead, in the deciduous teeth of children 7–11 years of age with celiac disease or food allergies that live in the Upper Silesia region in Poland. This region is characterized by a large concentration of heavy industry, such as coal mining and steel production, resulting in significant environmental pollution. To our knowledge, there are no previously published data on the toxic metal content in teeth of children with celiac disease or food allergies.