Home / Age Estimation / Forensic dentists claims bites by adults “more likely than not”.

Forensic dentists claims bites by adults “more likely than not”.

We know that determining a bite is from an adult or a child can be complex – especially when arch widths alone are used:

Arch width changes from 6 weeks to 45 years of age

And even the definition of “Adult” or “Child” with respect to dental development is complex – a legal adult may be 18 or perhaps 16 – but dentally – a child of 11 or 12 will likely have all of their adult anterior teeth.  Some authorities state that the presence of spacing, or other class characteristics of (especially) upper maxillary central incisors can help – but this, if possible, further reduces the upper age limit.  The following paper:

A comparison of the ability of experts and non-experts to differentiate between adult and child human bite marks using receiver operating characteristic (ROC) analysis. Whittaker DK, Brickley MR, Evans L. Forensic Sci Int. 1998 Mar 2;92(1):11-20.

Found that there was on average a 70% success rate from “Senior forensic dentists”.  3 times out of 10 they were wrong, however, truth in this case (i.e. was the bite caused by an adult or not) was established by the investigators – who could also have been wrong! The diagram on the left is taken from the paper.  Perfect agreement would be a line that was horizontal – a 50% chance (random) would be a diagonal line from bottom left to top right – as you can see the lines are closer to guess work than correct!  This makes the following story from The West Australian very concerning:

Full story here.

A forensic dentist giving evidence in a child neglect case against two Albany parents has told a jury bite marks found on an eight-month-old boy were from an adult’s teeth. The jury were shown images of bite marks on the infant’s knees and wrist last Friday, with forensic odontologist Dr Stephen Knott concluding after studying the images he was sure three of the six marks were from an adult’s teeth. Despite rigorous cross-examination by defence lawyer Helen Prince, Dr Knott said three other marks were “more likely” to be adult than child bite marks.

There is no scientific evidence to support that forensic dentists can safely assess child vs adult, especially to the degree required by criminal Courts.

About Odont1

Odont1 is a seasoned forensic dentist, researcher and educator with an interest in progressing the science of the discipline while retaining those elements that are evidence based and useful to the judicial system at any level.

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