There are many indications for ageing in living persons and an excellent paper by Jim Lewis and David Senn describes many of them.
When an individual reaches the age of legal majority, their treatment within the criminal and civil legal systems is changed dramatically in the United States. Forensic odontologists are often asked to assist government agencies in estimating the ages of persons who may or may not have reached that legally important age. The third molars are the only teeth useful as forensic estimators of chronological age in the target age group. This study reviews the principles, methodology, and population data of the most commonly used technique in the United States, the analysis of the third molar development based on modified Demirjian staging. The method analyzes the developing third molar to estimate mean age, age intervals and the empirical probability that an individual has reached the anniversary of her or his eighteenth birthday
The paper was published in Forensic Science International. The authors utilised the Demirjian staging system for looking at developing third molars. The stages have been modified several times and the two main modifications are the Solari and Abramovitch modifications:
And the Kasper modifications: