One aspect of a rpevious retrospective radiographic study was an examination of diameter and length changes of root canals at various ages. It was found that root canal shrinkage increased with advancing age. In the present follow-up study, a larger population (500 subjects) was used and only mandibular anterior teeth were evaluated. Root canal shrinkage was calculated vertically and horizontally. Measurements taken were tooth length, coronal length, apical length, root canal length, cervical width, midroot width, and apical width. Six age groups were examined: 17 through 20; 30 through 39; 40 through 49; 50 through 59; 60 through 69; and 70 through 79. Root canals showed statistically significantly more shrinkage with advancing age; there were significant changes among all groups. These findings could prove useful in anthropology and forensics and as an aging biomarker.