A tooth-oriented caries measure has limitations in depicting the caries experience in the primary dentition for a population. Caries patterns based on the child have been presented previously and quantified. The purpose of this study was to explore proportional changes in caries patterns of the primary dentition in two populations. Graphic representation is suggested in developing a model. Children two to five years of age were examined in a city pediatric dental clinic and in a suburban private practice and were categorized as caries-free or as having one of the following etiology-oriented caries experiences associated with lesion sites: Fissures, Hypoplasia, Facial-Lingual, Molar-Approximal, or Facial Lingual/Molar-Approximal. Over 85 percent of children aged 2.5 years or younger were either caries-free or fit the Facial-Lingual category consistent with descriptions of "nursing caries." Trends explored in this study would not be evident using an average for a tooth-oriented caries measure.