Not possible to gauge age using wisdom teeth

Medical age assessments are made when authorities cannot determine a person's age, mainly in asylum cases. In the new study, published in the scientific journal PLoS One, researchers focussed on the analysis of wisdom teeth which can be used as part of age assessment.

X-ray images of the wisdom teeth in the lower jaw are examined to see whether the tooth has fully developed at the root. The tooth may have reached various stages, based on a scale from A to H, which in turn can be linked to a certain age. Stage H corresponds to a fully developed wisdom tooth root, and this has been used as a signifier that a person has reached the age of 18. The researchers have made a systematic review that examines whether there is any scientific support for the method of age assessment.

“There are several difficulties connected to assessing age based on wisdom tooth root development. Issues can be caused because of how the X-ray was taken and whether the root apex is clearly visible. One must also respect and understand that we grow and develop differently depending on genetic and environmental factors,” says Gunilla Klingberg, a professor in pediatric dentistry at Malmö University.

The study, carried out with colleagues from Karolinska Institute, is based on an extensive literature search where they reviewed 2101 scientific publications.

“In the studies we reviewed, there were often questions about how the people included in the study were selected; their age distribution, and whether the person who reviewed the images knows anything about the person's identity, age and gender. Often the studies are based on existing journal material and the publications have not described why the persons were X-rayed or whether an identity check was carried out – all of this affects reliability.”

Through the quality review, 15 articles were finally identified which were judged to be of sufficient quality to be analysed further. However, the studies were too different for them to build up scientific support; they presented their results in different ways and the groups on which the studies were based were too different.

“The results of the study are therefore that there is currently no scientific support for judging whether a person is over or under 18 based on whether the root of the wisdom tooth is fully developed,” says Klingberg.

“Assessing the age of a person is very difficult; more studies from different parts of the world are needed to be able to make reliable assessments. For such studies, many people of several different ages are needed, and one must be able to ensure the identity of those who are involved.”

Text: Anna Dahlbeck & Adrian Grist