The purpose of this work was to develop a reference dataset for dental age assessment at the 10-year-old threshold. Dental panoramic radiographs of children aged between 9 and 11 years were reused to determine the age of attainment of tooth development stages relevant to the 10-year threshold. These data were used to test the accuracy of the dental age assessment (DAA) on a separate study sample of known chronological age. The study sample comprised 100 radiographs (50 female, 50 male) of known chronological age that did not form part of the reference dataset. For each subject in the study sample, the mathematical procedure used in meta-analysis was applied to all teeth that were still developing. The weighted average of all the developing teeth in a given child was assigned as the dental age for that individual. This was compared to the gold standard of chronological age. Three thousand six hundred sixty-two radiographs comprised the reference sample. The mean difference between the chronological age and dental age estimated for the sample of female subjects was 0.12 years (1.44 months) and for the males was 0.33 years (3.96 months). A method comparison technique was used to evaluate the difference between the chronological age and estimated dental age for each study subject. This showed a good agreement for both females and males. DAA using meta-analysis provides a simple method of estimating the age of subjects of unknown birth date at the 10-year threshold. This is, presently, the most accurate method of age assessment for individuals of unknown date of birth.