This study determined the prevalence of destructive periodontal disease affecting the deciduous dentition among otherwise healthy subjects, who were diagnosed with juvenile periodontitis (JP) in their permanent dentitions. There were 4,757 subjects in this retrospective, cross-sectional study. Diagnosis of JP was based on age (< or = 15 years), negative medical history, and radiographic evidence of arc-shaped alveolar bone loss. The study population was one-third white and two-thirds black and the male/female ratio was 1:1, reflecting the general patient population. The prevalence among whites was 0.3%, with a female/male ratio 4:1; whereas among blacks the prevalence was 1.5%, with a female/male ratio approximately 1:1. Among the black JP subjects with radiographs of the mixed dentition, 85.7% presented evidence of bone loss, and of those with radiographs of the deciduous dentition, 71.4% had discernible alveolar bone loss. This study suggests that JP is much more prevalent in blacks and that it does indeed occur in the prepubertal years affecting the deciduous as well as the permanent dentitions in otherwise healthy children. These data imply the importance of including a periodontal evaluation in the examination of children, using the periodontal probe and radiographs sufficient to adequately view the alveolar bone.