Early childhood caries (ECC) is a complex, multifactorial disease that poses a serious threat to child welfare. Although some risk factors and risk indicators have been identified, they have not been adequately investigated in specific ethnic groups or in very young preschool children. ECC is characterized by severe decay of primary teeth and in some cases, it is associated with inappropriate feeding practices. Iis prevalence varies from 5 percent to 72 percent depending on diagnostic criteria, age, race, and population. This study will focus on the earliest manifestations of ECC in the four maxillary anterior incisors. A case-control study is proposed to compare children aged 12 to 48 months with and without caries in the maxillary anterior incisors. The study population will be recruited from the dental and well-child clinics at San Francisco General Hospital, which serves an ethnically diverse, economically disadvantaged, urban population. Cases will be selected who have untreated caries in at least one anterior maxillary incisor. Controls will be selected who are caries-free in the maxillary anterior incisors. Parents or guardians of the children will be interviewed to identify factors that may be associated with the early manifestations of ECC. Children's saliva samples will be collected and assayed for cariogenic markers (mutans streptococci and lactobacilli levels; calcium, phosphate, and fluoride concentrations; and fluorapatite supersaturation). The specific aims are (1) to characterize and compare demographic, behavioral, familial, and environmental factors in an ethnically diverse group of underserved children wiht and without caries in the maxillary anterior incisors; (2) to assess cariogenic markers in saliva in the same population; and (3) to estimate the strength of the associations between the findings in specific aims 1 and 2 and the presence or absence of maxillary caries. Factors identitied can later be used in a prospective longitudinal study to develop a comprehensive risk assessment model for early manifestations of ECC in young children. Such a model would enable early detection and monitoring of at-risk children and lead to cost-effective intervention and prevention programs for this expensive and debilitating conditions.