Dr Richard Bassed, Forensic Odontologist

The Victorian Institute of Forensic Medicine would like to congratulate Dr Richard Bassed on receiving his PhD from Monash University. Based at the Victorian Institute of Forensic Medicine in Southbank, Dr Bassed is a Forensic Dentist and a doctoral student at Monash University.

The topic of Dr Bassed’s thesis is age estimation in both living individuals and human remains. The ability to assign accurate age estimates to human remains and living individuals is becoming an increasingly important element of forensic practice. In mass fatality events where many people have lost their lives and are often unable to be visually identified, being able to separate individuals based upon their age as determined by skeletal and/or dental development is a vital part of the disaster victim identification operation.

Age estimation also plays an increasingly important role in the assessment of living individuals of unknown age who have entered a foreign jurisdiction with suspect identification papers or with no identification documents at all. Determination the age of an individual – as either an adult or a child – is of vital importance in terms of how that person will be treated by the law in criminal prosecutions, immigration hearings, licensing applications and, increasingly importantly, determination of refugee status.

Dr Bassed examined three developing anatomical sites, two skeletal (the spheno-occipital synchondrosis and the medial clavicular epiphysis ) and one dental (the 3rd molar tooth) in an attempt to devise a method for more accurate age estimation of individuals in the range 15 to 25 years. I found that the multi-factorial approach reduced age ranges by approximately half, thus providing far higher precision and with no loss of accuracy at the 95% CI level.

ABSTRACT

This thesis examines three developing anatomical sites, two skeletal and one dental, in an attempt to devise a method for more accurately estimating the age of unknown age individuals in the age range 15-25 years. Individuals in this age cohort have been the subject of relatively little research as by the time a person reaches 15 years of age there are few anatomical sites still undergoing development, and all of these have been reported to be quite variable in developmental timing. The three age markers examined were the spheno-occipital synchondrosis, the medial clavicular epiphysis, and the 3rd molar tooth. All of these were examined using MDCT scanning as the imaging modality, and the sample was derived from the large database of post-mortem full body CT scans of deceased individuals located at the Victorian Institute of Forensic Medicine, Melbourne, Australia. The study sample consisted of 1006 full body CT scans of individuals aged between 15 and 25 years.

Each age marker was examined and a developmental score was applied according to accepted scoring methodology developed by others. Each anatomical site was individually assessed for its relationship with chronological age, and it was found that the 3rd molar tooth ad medial clavicle followed expected trends as to variability and developmental timing. The spheno-occipital synchondrosis was found to fuse earlier than expected in this population and had essentially completed development by the age of 17 years.

An investigation was undertaken to determine if combining 3rd molar and medial clavicle into one multiple regression analysis, the “multi-factorial approach” would result in an improvement in precision and accuracy of age estimates when compared to age estimations calculated using each age marker individually. It was found that the multi-factorial approach reduced age ranges by approximately half, thus providing far higher precision and with no loss of accuracy at the 95%CI level.

Further investigations were conducted to assess the effect of socio-economic status upon development in the Australian population with findings suggesting that there is no appreciable effect upon development between the highest and lowest socio-economic groups in this country. Left/right fluctuating asymmetry was also examined, with results suggesting that in approximately 3.4% of individuals the difference in development between left and right sides will have an appreciable effect upon age estimation calculations.

To contact Dr Richard Bassed, please email communications@vifm.org