Because bones and permanent teeth accumulate lead, exfoliated deciduous teeth have been utilized as retrospective markers of cumulative exposure in epidemiological surveys. In this paper we describe four models of lead uptake by the coronal dentin of shed primary teeth, each with different assumptions and ramifications. Each model is characterized by different relationships between blood lead at several ages and tooth lead. Values observed in our cohort of normal Boston children are most compatible with models positing the largest lead contribution coming at older ages (i.e., closer to age at exfoliation). Characteristics of models incompatible with our data include (1) lead deposition only during initial calcification and (2) no loss or resorption of lead.