Bite Marks and Dental IDs
Everyone’s teeth start off looking a bit different from anyone else’s. As you age and don’t brush your teeth, fall face first into concrete, and bite down on too much hard candy, your teeth get more and more unique. Many people go to the dentist at some point in their lives and have x-rays of their teeth taken as well as having the dentist write down everything wrong with your mouth in their chart. You know what else is great about teeth? They survive just about anything that would destroy other methods of ID like faces or fingerprints. Like fingerprints, teeth can leave impressions on objects they touch. If you bite something, you leave teethmarks. If you are missing your two front teeth, you’ll see a noticeable gap where they would have hit the object! The first area, dental ID, is rock solid, easily explainable, and given the circumstances is rarely the sole piece of evidence as to a person’s identity. The second area, that of tooth impressions on surfaces, is one of the largest travesties inflicted on the legal and scientific community ever. You cannot be angry enough about bite mark analysis. Imagine the most horrible miscarriages of justice you can and they have probably happened in a bitemark case. It gets my blood boiling just thinking about it. I’ll be outlining a LOT of anecdotes at the end of this piece.
Before I get to THE HARD FACTS, I’m going to flex my writing muscles and present all of you with a hypothetical. If I mixed in other forensic sciences, it would make a decent final exam question for a class on forensics if I cut out most of the useless irrelevant information. It also gives me a good architecture to discuss dental IDs and bitemarks without getting enraged and sidetracked by real people.
Let us assume for one moment, that you are a serial rapist. You have a particular pattern. You force a woman at knifepoint into an alley, rape her, and both during and after the rape you just bite the shit out of her back and buttocks. Eventually a victim finds you and exacts personal revenge, which culminates in that person dousing you in kerosene and lighting you on fire. By the time a city inspector discovers your body 3 days later, you are not but a skeleton. A crime-scene unit hauls your desiccated remains to the medical examiner even though there’s really not much to examine. “What to do, what to do?” wonders the 2nd year pathology resident who is stuck doing a rotation at the city medical examiner’s office with an obese senior pathologist who thinks it’s just “a shame” that a “young lady” wants to do such grizzly work. Lucky for her, she is already friends with a local dentist, Steve, who took two weeks of night classes on forensic dentistry and went to a 6-hour seminar on forensic odontology.
She calls up her buddy, and he heads on over to look at your teeth. The dentist cracks open your heat-sealed jaws and starts to work. He counts all the teeth, looks for any dental work, observes any chips, strange orientations and the like. Finally he is able to take a dental x-ray after our plucky path resident finishes with the corpse and removes your practically dangling skull for him to hook up to a panoramic dental x-ray machine. With all these data in hand, he heads back to the office to do some fillings and abuse a prescription medication available through his practice. Let’s further assume you were a resident of California or for whatever reason the FBI had a record of your teeth. Steve looks up your teeth in the California database and voila, there you are in the missing persons database! Now you have a name, John Serial Rapist. Steven thinks this name is pretty weird. He also collects forensic photographs of rape victim bitemarks and tries to match them to the California and national database as a hobby. You, JSR, have a somewhat normal dental history but Steve is suspicious because he is particularly familiar with bitemarks from the area not to mention your particularly suggestive name. He starts looking through his photo collection and decides, based on bruise and wound patterns, that you bit a whole lot dead bodies!
An inquest is opened based on Steve’s analysis. Many unsolved rape-murders are attributed to you! As the media sensation grows, the sheer volume of crimes you are alleged to have committed are reaching implausible levels. Your parents, Susie and Sam Rapist, having borne a lifetime of discrimination based on their family name, hire a particularly adept lawyer to participate in the inquest with the goal of clearing your name. This lawyer hires his own forensic odontologist, Danny Dentist, to review the evidence. Danny looks over the pictures and concludes there are several possible matches between victim bitemarks and your bite pattern. However, your teeth are not particularly unusual so he decides he cannot state with any certainty that you were the biter to the exclusion of all others. Furthermore, as he gets to the later accusations he comes to a startling revelation. Many of these photographs aren’t even bitemarks! Danny is just a dentist but some look like bug bites, animal bites, the acts of flesh decaying, or a product of where the body was found. Danny tells all of this to the lawyer. The lawyer is concerned! Danny is concerned!
Danny decides to call Steve and ask just what the hell Steve thinks he’s doing. Steve refuses to change his conclusions. Danny, disgusted by what he feels has become intentional and knowing falsity, testifies adamantly at the hearing in your posthumous defense. Steve calmly states that he is 100% certain that you left all the bitemarks, even the ones that might not be bitemarks at all. The inquest is, by now, a daily news story on every national network. Steve’s intrepidity in finding a previously undiscovered mass rapist is lauded and he starts to get many offers from prosecutors all over the country to analyze their bitemark evidence. Danny’s eloquent, simple, and seemingly obvious explanations get a lot of notice from defense counsels and he starts to get a lot of calls from defense lawyers asking him to testify counter to Steve! An epic showdown ensues on a national scale with Steve and Danny dueling in courtrooms from Mississippi to Massachusetts. Steve usually “wins” in that jurors, when polled after trials, overwhelmingly believed him over Danny and found the presented evidence to be extremely important in helping them reach their conclusions.
Analyze the issues that are glaringly obvious in this hypothetical with special focus on the use of dental evidence!
Part the First – Identification using the Dental Sciences!
What do you do when you find a skeleton buried in a field? What about when an unknown body is found at the scene of an abandoned warehouse? What if someone died in a field and coyotes and ravens have been at it for a week? What if their body decomposed under circumstances where there was a lack of atmospheric oxygen (e.g. underwater)? What if the Duke Leto Atreides cut off the person’s hands so he could send them back to the Baron Harkonnen filled with spice? A fremen medical examiner is going to have to rely on alternate methods of ID than fingerprints and now that computers have all been destroyed DNA analysis takes like a jillion years! Luckily, most dentists can do dental IDs with only a minor amount of additional training. The techniques are almost exactly the same as what a dentist does during ordinary work so it’s not hard to believe it doesn’t require a lot of additional expertise.
Dental IDs rely on the same premise as all other identification-type forensic sciences. Any object quickly accumulates unique marks through use, aging, materials, manufacturing defects, and the like. These unique marks, when taken as a whole, can be used to conclusively assert the origin or identity of the object. You’ve seen this assertion already in NAA, fingerprints, voice ID, and firearms ID. As we now know, where the object has sufficient uniqueness, sufficient transferability of that uniqueness, and sufficiently analysis of that uniqueness, you can sometimes claim a mark or an object is the original. It works with NAA, maybe with firearms, maybe with fingerprints, and definitely not with voices. In this case, we can actually eliminate most of the confounding issues we’ve seen in previous areas!
Here there is no transfer of uniqueness. Instead all a dentist is trying to determine is, are these teeth the same as the teeth described in this other source of information I have. All we need then is for teeth to be sufficiently unique to allow for an assignation of identity. People start with 32 teeth and each tooth has five surfaces. That is a lot of evidence real estate. Unfortunately for teeth owners but lucrative for dentists, teeth accumulate “uniqueness” right away. You bite down on something too hard, you don’t brush, you don’t floss, you get dental surgery, you get cavities filled, you get teeth pulled, or you take a mouth full of stairs because you were drunk. These issues alone can create sufficient uniqueness. However, even in distant lands, people needed dental treatment to address their mouth problems. Modern dentistry and dental treatments are phenomenal for both their efficacy and their installation of unique identifiers. The material used in your filling, the maker of your crown, the method of root canal you received, the type of ceramic used in your implant, the type of braces you had, whether you had braces, whether you grind your teeth, whether you thrust your tongue all combine to form quite the orgy of evidence.
The major problem is narrowing putative IDs to a scale where a dentist can obtain their dental records for comparison. There really aren’t very many tooth record databases until just recently. I know California maintains a database and I know the FBI maintains dental records for their missing person database. Note that the fact the FBI keeps it in their missing person’s database is not a good sign for the survivability of missing persons. In any event, if you don’t have a ballpark idea of who that dead body is dental records probably aren’t going to assist you in identification. However, if you do have a general idea then dental IDs are amazing in helping to ID otherwise totally unidentifiable remains. Furthermore, once you have a tentative ID through dental records a lot of other evidence can be reviewed to confirm or deny the accuracy of that ID.
Let’s look at the hypothetical again. Steve did a rigorous recordation of the corpse’s teeth as well as taking a full and detailed dental x-ray. He then looked in the California database of missing persons and determined that the x-rays and analysis he did matched up with our pal, Johnny. Assuming the records contained in the database were accurate, the ID is probably good. IF there were x-rays in the record then the ID is probably unassailably conclusive.
Remember one of the crucial determinations for identification. ID can be destroyed by a single unexplained discrepancy. Given what we know of dental science and the existence of multiple records and x-rays, any discrepancy should be explainable and there should be a whole heap of matching points. If John had any more serious dental work done then these implants or crowns can be analyzed to further confirm his identity. Finally, with the putative ID in hand, authorities can look back at when and under what circumstances the remains were found to confirm the ID. John went missing around the same time as the corpse was found and both the corpse and John were missing their left big toe. Sounds like we found our man!
Part the Second – BIIIIIIIIITE MAAAAAAAAARKS!
As discussed above we already have a basic understanding of how to establish identity of source from analysis of impression. Unique thing touches object, transfers unique qualities and unique qualities can be analyzed in a way that allows for determination of original unique thing. Fingerprints and firearms work the same way. As discussed previously there is no magic bullet to this analysis. Every single assertion must be studied, analyzed, and reanalyzed. People’s lives are literally on the line. Are teeth unique, do they transfer that uniqueness upon contact with other things, and is that uniqueness capable of being analyzed by an expert?
First, a mouth full of teeth must be unique. Everyone would agree that a specially inscribed crown would be unique. What about a 10-year old child’s teeth? What about a 12 year old? An 18 year old? An 80 year old? Obviously, as time passes people will accumulate more and more unique aspects but are they unique from infancy? One might think the analysis done above would assist us in this determination but it doesn’t as much as it could. Identifying a dead body relies on a wide variety of tools and investigative techniques. Most recently, DNA analysis has provided unassailable evidence of identity so the reliability of dental IDs have taken a backseat. Furthermore, dental IDs aren’t going to be used directly to convict someone. They are just identifying a body. Like many of the other ID techniques, there just haven’t been any real studies to assert that teeth are unique from birth or that there is a specific age where a person’s teeth attain uniqueness. Uniqueness is just assumed.
The other key difference in analysis comes into play with the second factor. When looking to make an ID based on x-ray to x-ray, dental record to dental record, a dentist is comparing all the available teeth to all the available teeth. In a bitemark, the biter only leaves the impression of some teeth on the object. A person doesn’t put an entire apple all the way up to their molars to take a bite. A person defending him or herself doesn’t wait until they can fill their mouth to the brim before they bite a dude’s forearm. Bites aren’t going to involve all the teeth in your mouth, only a few of them will leave impressions. That is the first major problem with the transfer of uniqueness. The second problem is the surface into which someone bites. Skin is a terrible surface to take impressions from. It deforms and changes rapidly when a person is alive and when they’re dead. If the surface is a food item then that item will assume dental impressions based on a vast amount of unknown factors. Every type of food is pretty unique from a texture perspective. There are, as far as I know, no standards or compendium for surfaces and their changes in relation to bite impressions over time. A bite in skin will swell up and start to heal right away and a corpse will begin to settle and dry out immediately. Who knows about food because there are a nearly limitless number of objects you could test. Another twist to the unique surface puzzle is that a surface will deform while the bite is taking place resulting in a “final” bitemark that is very different than the bitemark observed when the skin is observed in a more compressed position. Try this out if I’m not explaining it adequately. Put your forearm in your mouth. Gently rest your teeth on the skin. Now press down a bit and try to feel how the skin and muscle move. That would leave a different mark if you pierced the skin at this stage than if you broke the skin while just resting your teeth. Guess what is photographed? The “relaxed” skin. Presently there is no accepted or, as far as I’m aware, particularly accurate way to correct for the surface deformation that happens during a bite. Further, these transfer hypotheticals assume a laceration. You don’t need to break the skin to leave a bruise. Many experts assert that they can make bitemark IDs based on bruise patterns left on someone’s body. All the issues with lacerations are double for bruising. Finally, just to add more uncertainty, we don’t know if there is a difference between bitemarks when teeth are used in a violent manner and when they are used for eating. Given that it’s not unheard of to use food items to compare to a corpse this is VERY IMPORTANT!
Third, there is the analysis of the bite. There are so many problems with the analytical methods applied to bitemarks I barely know where to begin. Many of the problems are outlined in anecdotes and cases that I will go over in more detail later. Suffice it to say, there are almost no standards for the analysis technique employed, the application of the technique, the amount of uniqueness required, the education level required, or the experience level required! In short, dentists have been able to employ any logical way you could imagine to analyze bitemarks and all have been admitted. Finally, given that there is no standard or scoring system to determine if a bite has enough points of uniqueness to confirm an ID, the analysis is fundamentally a subjective decision that varies from dentist to dentist. The analysis stage is a goddamn mess and if you are a dentist, you should feel ASHAMED.
However, there are a few techniques employed more widely than others. The bite is always photographed extensively. If there is any laceration or three-dimensional component then molds of the bite should be taken. The suspect’s teeth should be extensively recorded with observation, photography, and dental impressions. Fancier dentists will make full models of the teeth and bite then lay them over one another. More ordinary dentists will use photographs to create transparent overlays to make the comparison. In modern times, there have been a wide variety of computer assisted graphical techniques employed. Think of a way to compare what are fundamentally two photographs and it has probably been used in court at some time. Ultraviolet photography has been used to display bruise patterns better. I had forgotten about this before reviewing my materials but apparently, bitemarks are cut out of corpses for analysis. God knows what variables this introduces but I guarantee it hasn’t been studied. Analysis has a practically infinite amount of excuses to explain inconsistencies – the bite was swollen, the body dried out shrinking the bite, the person sucked in the skin before they bit, the victim was conscious or unconscious, the skin was especially different in this area explaining this inconsistency. It goes on and on.
So, what the hell can you draw from bitemarks? You can eliminate obvious or glaringly incorrect suspects. If they’re missing teeth or have an odd tooth orientation, then there is no way they could leave certain bites. Using bitemarks to eliminate suspects is common but not headline getting. It also doesn’t result in innocent people being put on death row.
Again, let’s go back to the hypothetical. Steve was pretty sure that John made all those bites! Danny was less sure and didn’t even think all the marks were bitemarks. Who was right? Danny was right by default! There’s just no evidence to support making bitemark IDs and there’s no standard for determining what is and isn’t a bitemark on a corpse. THIS SHIT IS MADE UP YOU CAN NEVER KNOW IT IS A GODDAMN BLACK HOLE!
The Statistical Evidence behind Bitemarks!
Here is where it gets really ugly. It gets super gross and disgusting. Once you read these numbers, you are going to be pretty upset.
There is an actual governing board called the American Board of Forensic Odontologists. There’s also the American Society of Forensic Odontology. I have not mentioned them until now because you don’t have to be a member to testify as to dental IDs or bitemark IDs. They also set no standards or guidelines! The ABFO thought it might set a guideline in the 80’s and created a scoring system but then recommended that no one use it and said it was probably shitty anyways so they don’t know why they bothered.
As far as the stats on bitemark IDs? In 1975, a study showed that under perfect conditions, there was a 24% error rate and if the bites were 24 hours old, there was a 91% error rate. The ABFO had a seminar in 1999 where their 4 “diplomats” did a demonstration for everyone – there was a 63% FALSE POSITIVE RATE. In 2001, a study showed a 22% false positive rate! HOW IS THIS EVIDENCE ADMISSIBLE HOW IS THIS A REAL THING AM I IN THE MATRIX!
That’s it for stats on bitemarks. There have been no statistical studies on ANY aspect that I have described above as far as I am aware. NONE. NO STUDIES. NO ONE KNOWS.
The evidence for bitemarks is SO AWFUL that the seminal bitemark case, People v. Marx (1975), involves a lengthy explanation on why they don’t have to follow the required and prevailing standard of scientific evidence. Oh THIS evidence? Well I rule you can just let it in regardless of scientific backing BECAUSE I AS THE JUDGE FEEL PERSONALLY CONVINCED! (Seriously!) Did I mention the case involved a method of comparison never used before that case? Oh? Well it did! It doesn’t matter anyways because all the courts who have considered the evidence under the Frye standard have accepted it anyways. I’m not entirely sure if there has been a challenge under the newer more stringent standard of admissibility.
Hilarious Story Time – If you aren’t mad by now, you are about to get super mad.
Let’s start with some cut and dried cases. In 1995, two highly experienced experts concluded that a defendant, Krone, had bitten the murder victim. A decade later, he was exonerated by DNA evidence.
In 2005, an expert claimed there was a “4.1 billion to one” chance that anyone other than the defendant made the bitemark on the victim. Turns out the semen in her body ended up not belonging to the defendant.
Again in 2005, an expert claimed the bitemark was definitely made by the defendant. THAT SAME DAY an expert CONCLUSIVELY excluded the defendant using the saliva found in the bitemark! Idiots.
Now for some“borderline” cases:
In 1976, three experts testified the bitemarks were a match for the defendant on behalf of the prosecution. Four experts testified for the defense and testified either that a match couldn’t be made based on available data or that the defendant conclusively wasn’t a match. He was convicted. Later it turns out he was exonerated by other evidence but actual innocence is not a defense at law and his state appeals were already exhausted so GO FUCK YOURSELF MILONE!
In 1984, four experts testified for the prosecution and three for the defense. The prosecution experts of course testified that the bitemark was a match to the defendant. The defense experts testified that the marks WEREN’T EVEN BITEMARKS! However, they concluded that even if you assumed they were bitemarks they couldn’t have been left by the defendant. Convicted.
In 1987, prosecution experts testified the bitemark was a match, defense experts testified that the wound was not a bitemark. In this case, they were able to prove conclusively that it was NOT a bitemark! Three trials later and the defendant was acquitted.
Now the ultimate story – Dr. Michael “That Motherfucker” West. Dr. West is a fat, ugly lying slob of a man. He has been ejected from all the professional associations affiliated with bitemarks on the basis of massive incompetence and “possible” intentional falsification of evidence. He was later readmitted. I have been privileged to witness a demonstration by Dr. West on a bitemark ID. It was not a match if you, I, or anyone with eyes looked at the pictures. Nevertheless, Dr. West and his expertise just made up a whole load of shit and explained away at least three discrepancies with LITERAL HANDWAVING. He has invented analytical techniques that have no scientific validity. He has made claims with no basis in fact repeatedly. The man is a menace. By his own admission, he has made 300 bitemark IDs. Are any valid? I have strong reservations! According to the opinion of a Mississippi Supreme Court judge, of the 100 forensic bitemark experts, around 90 of them have testified AGAINST Dr. West. Dr. West is a perfect case study in how Mississippi IS A TOTAL BACKWARDS SHITHOLE.
In a 1997 case, he claimed that bitemarks were unique and could be traced back as well as fingerprints. This case went to the Mississippi Supreme Court three times and was reversed twice. On the third time they finally upheld the conviction the dissent demonstrated that not only was the conviction erroneous but that the only evidence linking the defendant to the crime was a detective’s hunch and the bitemark ID (which was likely made up in its entirety by DR. WEST!)
I have just begun to explain his infuriating and inexplicable wrongness! In 1994, he said that there were a whole shitload of bitemarks all over a victim. Turns out, they were ant bites! In 1992, he again swore bitemarks where there when there were no bitemarks! Even if they were bitemarks, how do you match amorphous blobby wounds to teeth? No one knows but Dr. West!
In a later case, he conclusively matched a defendant’s teeth to a bitemark but “lost” all the evidence – the mold, the sandwich, and even the mold of another suspect’s teeth. Whoooooooops!
He is also the only expert IN THE WORLD about “wound pattern analysis.” WHO KNOWS WHAT THIS MEANS NO ONE KNOWS BUT IT LETS HIM CONCLUDE BLOBBY BRUISES ARE FROM SPECIFIC ITEMS!
In 1998, Dr. West testified that 19 bitemarks on a victim’s body were matches to the defendant. The only problem is there were no lower teeth marks from any of the bites! Dr. West had the audacity to claim that the defendant’s lower teeth just weren’t very sharp. He could not explain this AT ALL! HE HAD NO IDEA! The founding member of the AFBO testified against him saying that NONE of the wounds were bitemarks.
When he was suspended or ejected from EVERY professional association having to do with forensic identifications HE WAS STILL PERMITTED TO TESTIFY.
There is MAYBE some hope that courts reviewing bitemarks under the newer more stringent scientific standards along with the generally rising quality of attorney representation on bitemarks will lead to a revolution in this area. I doubt it.
AUGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH THE LAW THE COURTS THE RULES OF EVIDENCE AUGH ALL DESTROYED BY BITEMARKS