It seems I’m now on a crusade to cajole folks about making sure forensic odontology procedures and principles are based on valid and reliable fundamentals.  Many of the odonts are replying to my call with “Oh, yes, our presentations are solidly based on science!”  I’m certainly glad they think so, but is this actually true?

   First, here are some passages from Pago regarding validity and reliability, and these are about as good as any:

            “Validity refers to the ability or the potential of our data collection tool to capture and measure the construct or the phenomenon that we are interested in measuring. Are our questions/tests/other measures reflecting the real meaning of the concept under       consideration? Regardless of our study’s focus, we must ask ourselves how we will scientifically measure it. Once we have a clear idea about how to measure our concept, we must make sure that the way we have decided to measure a specific construct actually does so (emphasis added)…

            “Construct validity is similar to content validity in that it measures the level or the degree that a measurement is able to truly measure the construct in question. 

            “Reliability is the consistency in our measurement. We can state that our data collection instrument is reliable if it will yield the same results even if used with different subjects, different populations, and/or different settings…” (Pajo, 2018).

   Validity of a method means, then, we are actually measuring what we think we are measuring, and reliability means that our method works over and over.  Further, we also have internal and external validity considerations--essentially internal validity means the method worked in our limited and controlled study, while external validity means it also works out in the real world.

   How does this apply to the very diverse disciplines of: i) identification of human remains by use of dental records and radiographs, and, ii) bitemark analysis?

   Well, first off, there is no research to show that either procedure really is valid or reliable.  None.  We simply assumed fundamental precepts are true and forged ahead.  We assumed dentists can look at ante- and post-mortem dental radiographs and correctly either “match” or exclude them as arising from the same source. 

   It seems we can do this—but do we know our error rate?--that’s a big issue in the US.  How do we measure the similarity or dissimilarity of appearance of, say for example, an MO amalgam on tooth #30 (46 FDI) on the ante- and on the post-mortem radiographs we are comparing?  We look for “consistencies,” “explainable inconsistencies,” and “unexplainable inconsistencies.”  How do we measure those?  How do we measure how “explainable” an “explainable inconsistency” is?  How do we ultimately decide there is or is not a “match”?  These are the most basic and common things we do in forensic dentistry, yet we have no scientific proof of validity of our protocols and procedures.

   But, at least looking at dental radiographs is something we do all day long in our clinical practices, and it seems, although it is not lost on me that I state this without any proof, that there are very few errors made via dental identifications—at least we don’t hear reports of mis-identifications, and that is something that would certainly come to the attention of practicing odonts if it did happen.

   Bitemark analysis, IMHO, is an entirely different ballgame, though.  Oh sure, we are pretty good at making models of suspect’s teeth but, truthfully, that is about where our genuine expertise begins and ends in analysis of patterned injuries.  We are not taught to forensically evaluate cutaneous injuries in dental school.  We rarely, if at all, see bitemarks on our patients in our practices.  We are not experts in photogrammetry and metrology.  We are not real experts in using software such as Photoshop.  Most dentists have not seen hundreds and thousands of cutaneous patterned injuries as part of our actual jobs. 

   Yet we do not “stay in our lane.”  Some of us have been willing to get on the witness stand and testify with hubris that the defendant was “indeed and without doubt” “the biter” to the exclusion of everyone else in the world and send him/her off to prison for the rest of their life.  And, yet, there is absolutely no research showing the validity or reliability of the procedures.

   You might note that I usually exclude dental age estimation from my rambling pontifications.  Dental age guesstimation has a veneer of respectability and a lot of research has been done on age guesstimation methods.  This is my topic of research in graduate school and I’m not anywhere near ready to publish yet, but I believe it will be found there are some serious and fundamental issues with the way we do these guesstimates and use them in legal proceedings.

   Please spare me the hollow and shallow arguments about pattern-matching disciplines being as much “art” as “science.”  I’ve made all those similar arguments, myself.  Please spare me the argument that the folks who wrote the “NAS Report” (Strengthening forensic science in the United States: A path forward, 2009) were not experts in the various disciplines, or weren’t real scientists or, gasp!, some of them were attorneys—I’ve made all those arguments, too.  Well, I could become a certified astrologer, and an attorney who points out that astrology is not real science is not automatically wrong simply because she is an attorney.  And further, just because astrology uses some of the science of astronomy does not make astrology a science.  

   Resisting or resenting or refusing a call—from anyone--for more, or even a little, actual science in one’s field is simply being no better than a neo-Luddite.  After all, if one’s field is really valid, then the science will show that, no? 

   And saying, “well, I have experience and I know what I’m doing!” is the height of superficiality and arrogance and not all what the scientific method is about—you know, in my unexamined daily experience it sure seems like the Sun is orbiting the Earth, but, then again, I might be wrong about that.

   So, if you say you are "following the science" but you don't verify for yourself that the "science" is actually true, well, that's merely a leap of faith like religious folks and cultists make.

   When folks say they are presenting forensic odontology material that is well-grounded in science, I sincerely hope they are.  Because, so far, no one else has been able to do that.

Pajo, B. (2018). Introduction to research methods: A hands-on approach. SAGE Publications, Inc.

Strengthening forensic science in the United States: A path forward. (2009). National Research Council, The National Academies Press. https://www.ojp.gov/pdffiles1/nij/grants/228091.pdf