AbstractBackgroundHeavy metals including Cr VI are present in inadequately treated effluents that contaminate drinking water. Hence, Cr VI exposure can affect children through intake of breast milk from an exposed mother or bottle‐feeding formula prepared with contaminated water. To date, there are no reports on the effects of Cr VI exposure on tooth formation processes concomitant to tooth eruption.AimTo study the effect of Cr VI exposure on tooth tissue formation in suckling Wistar rats by assessing dental tissues at different stages of tooth eruption.DesignExperimental animals received 12.5 mg/kg body weight/day of a potassium dichromate solution by gavage; control animals were similarly administered an equivalent volume of saline solution. Each group was divided into three subsets according to age at euthanasia: 9, 15, and 23 days. Dental formation was analysed histologically and histomorphometrically. Statistical analysis: Student's t test; P < .05.ResultsCr VI‐exposed animals showed a delay in mineralized crown and root tissue formation. These findings are directly associated with the observed delay in tooth eruption.ConclusionOur findings show the importance of monitoring drinking water levels of toxic substances, since exposure during early childhood can alter tooth formation, growth, and development.