Accurate methods of age estimation are more essential than ever due to the rise in undocumented individuals without proper identification, often linked to illegal immigration and criminal activities. This absence of reliable records presents challenges within the legal systems, where age thresholds in the context of children’s rights vary across countries. Age 14 has global significance, as established by the UN Convention on the Rights of the Child and the EU for administrative purposes. Accurate age estimation is crucial in medical decisions, reproductive health, and forensics. This study focuses on age estimation via dental radiographs, proposing a method for estimating the likelihood of having attained the age of 14. Orthopantomograms were analyzed from two samples, 191 Italian children (aged 5–15) and 822 Chilean subjects (aged 11–22), using dental maturity indices. These indices evaluated open tooth apices and complete root development. Statistical analysis confirmed the method’s reliability in identifying individuals aged 14 or older, with sex-specific cut-offs. The proposed method particularly advocates an approach based on dental mineralization, which could surpass those relying on bone growth. The collaboration between medical experts, including pediatricians and diagnostic imaging specialists, is vital for standardized age estimation strategies. Ethical concerns regarding radiation exposure and accountability are recognized, although the method’s low radiation doses are deemed acceptable. The proposed method will help health professionals to accurately predict whether or not the 14-year threshold has been reached, opening up new avenues of medico-legal interest and laying the foundations for a legal framework that would allow the pediatrician, when involved, to use a valid and recognized diagnostic approach.