The use of dental characteristics to determine the age of an individual is now common practice, having first been introduced professionally in the early nineteenth century as a way of confirming a child’s age during criminal proceedings. Later, researchers employed similar methods to calculate the age of a deceased adult. Since then, forensic investigators have increasingly utilised the growth, appearance, and size of teeth to estimate age and confirm the identity of people in situations where this is unknown or disputed. This method was formalised through published guidelines which included six age-associated changes, relating to the structure and configuration of the teeth and surrounding tissues. Researchers also increased the accuracy of the technique by assessing the developmental stage and measuring the amino acid composition of the tooth.

It is important that assessing these attributes is as non-invasive and accessible as possible since such procedures are often used to evaluate the dental anatomy of living individuals. Researchers have developed many strategies to produce a detailed vision of target structures with minimal intrusiveness and discomfort. Dental clinics routinely use advanced non-destructive imaging techniques which generate static images of the inside of an individual’s mouth. The clinic can then analyse the images to aid in diagnostic procedures and identify any potential issues. Several approaches are now available depending on the desired outcome and can be used to visualise anything from the entire mouth to specific properties of a single tooth. Previously, researchers have used such images to determine how the length, width, and broadness of teeth pulp cavities correlate with age. This method was developed by Dr Sigrid Kvaal in 1995. Specifically, the pulp cavity typically shrinks with increasing age due to the accumulation of mineralised material which initially occurs following full tooth maturation and continues throughout life.

Dr Hosam Alharbi of the Dentistry department at Qassim University in Saudi Arabia, along with colleagues from other institutes in Saudi Arabia and Finland, conducted an interesting research study to apply the Kvaal method to dental radiographs that show several teeth at once. They evaluated whether the broadness of the pulp cavity, as viewed on such a panoramic dental image, could be used to accurately verify the age of an individual. This technique could be very useful as it employs a specific image type routinely generated during dental consultations, and potentially widens the general application of this age estimation method.  

To perform the study, seventy-four recently generated digital dental images were randomly selected by the researchers from the existing bank of patient records at Dr Alharbi’s clinic. All belonged to adults, with the mean age being thirty-two years. Only those patients with a complete set of six visible specific tooth types, three of which were positioned in the lower jaw, and three in the upper jaw, were eligible for inclusion. The absence of damaged or abnormally positioned teeth was also a prerequisite for involvement in the study, whilst pregnant women and those diagnosed with certain medical conditions were excluded to avoid external factors which might skew the findings. Using a computer software programme compatible with the digital image formatting, a single observer studied the pictures to minimise intra-operator variability. For each of the six specified teeth, the observer recorded both the length of the tooth and root and the length of the tooth and pulp cavity, along with the width of the root at three separate areas spanning the pulp cavity, labelled A, B, and C.

The researchers grouped the patients according to one of five age sub-divisions, and performed statistical analysis to ensure the robustness of the findings and to facilitate meaningful comparisons between patient groups.

The results included the pulp and root width at level A, B, or C for each tooth, and the researchers used statistical analysis tools to determine whether there were any differences between the estimated and actual age. The study considered each tooth individually, all teeth together, or grouped the teeth from the upper and lower jaw jointly.

The researchers discovered that, based on the analysed panoramic digital images, there was no significant differences between the estimated and real patient age. Furthermore, they found that certain width/length measurements and consolidating all six tooth types resulted in a more accurate appraisal. This clearly demonstrates that images showing several teeth at once can be feasibly used to precisely determine the age of an individual when particular measurements are applied.

This modified version of a routinely used non-invasive technique is important to expand the ways in which age can be estimated using readily available patient data and equipment. This not only reduces the need for additional training, but also bypasses the extra costs associated with purchasing new apparatus and software and promotes patient safety because of the lower radiation dosage required for imaging. Thanks to the comprehensive investigation conducted by Dr Alharbi and colleagues, great strides have been made towards improving the scope of age estimation methods with increasing relevance to a larger number of forensic procedures, because of the accessible materials and techniques used.

Given that dental idiosyncrasies, such as root length and cavity size, are known to differ between demographic and ethnic populations, it is important to broaden the number and type of subjects assessed in future research, ideally involving many males and females of all ages across many countries. This would validate the potential of this age estimation method on a global scale and further support panoramic digital imaging in forensic dentistry evaluations. This could potentially revolutionise age determination techniques in living and deceased individuals during both criminal proceedings and for archival studies.