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Category Archives: Forensic Dentistry

Are Bite Marks Junk Science?

The forensic examination of bite marks left on victims, both alive and deceased, is being brought into question. If someone has an unusual tooth pattern and leaves bite marks on a victim, it seems logical that a match between the tooth pattern and the bite mark pattern would indicate that this person was the one who did the biting. And that just might be the case.

Bundy

 

The poster boy for serial killers, Ted Bundy, had an unusual dental pattern and was convicted in part on bite mark evidence. No doubt old Ted was guilty but was the bite mark evidence used against him reliable?

 

Bundy's Teeth

Bundy’s Teeth

 

It comes down to exactly how accurate these comparisons are?

28santos.600

 

It mostly depends on the “quality and clarity” of the bite mark and the skill, experience, and attention to detail of the observer. The key being that it varies from case to case and from examiner to examiner. Forensic science doesn’t like such unpredictable variability. In general, such variability means that either the technique is not useful or accurate, or the protocols for making the comparison are inexact. Time will tell, but a couple of upcoming court rulings could derail the entire process. We shall see.

AZ Daily Star

The Daily

 

 

Guest Blogger: Forensic Dentist Stanley Woods-Frankel

Forensic Dentistry
Forensic dentistry is not a new science, since it has been around  since the civil war and refined during the late 1800s. Dentists helped identify bodies found after huge fires had claimed many unrecognizable victims, such as the Chicago fire, the shirt-waist fire in lower Manhattan, and the major conflagration under the tents of a Paris outdoor fair. A burst dam in the Rocky Mountains that killed over 500 people who lived in the valley below should also be included. In modern times forensics was a major factor in airline crashes, and of course 9/11.

The method that most Forensic dentists use now is to chart the mouths of victims who were too ravaged to be recognizable or have enough skin on their hands to have fingerprints. The jaws should be worked open enough so that the dentist could chart the mouth, and that X-ray films could be placed next to the teeth and a full series of X-rays could be taken. All abnormalities should be noted, as well as what teeth are missing, what fillings are present, what teeth have been replaced by either fixed, or removable appliances,and  which teeth  have had root canal treatment, or implants.

 

Once this process has been completed, the dentist or their assistant takes a history to find out what people might have been present at the occurrence, and then contact the various dental practitioners who might have worked on them, and request a copy of their records. If a match is not close enough for a definite comparison it can be confirmed with further DNA Testing.

If none of this is possible NCIS has to be contacted which would list all the people who have been declared missing, and many times the dentist can find a match.

If none of the above works, after a certified time in cold storage, the remains are buried in Potters Field which is a small island off City Island  by convicts from Rikers Island, If necessary the bodies can be exhumed at a later date.

In my first novel, False Impressions, which is due out on August 1st, the main character, the irreverent Forensic Dentist,  Steve Landau, performs all these duties in a much more humorous, but dramatic fashion, and could be an enjoyable, as well as educational way to get your facts. Dr. Stanley Woods-Frankel can be contacted via his web site:

http://www.writingdocfrankelswoods.com

 
 

New Green River Killer Victim?

One of the most notorious and frightening serial killers in history was known as The Green River Killer, a moniker derived from his dumping his victims, mostly prostitutes, along the Green River near Seattle, Washington. Between 1982 and 1991, nearly 50 murders were attributed to the killer. The task force assigned to the cases developed a long suspect list but had no conclusive evidence that implicated any of the men.

One of the intriguing things about this case is that it parallels the advances in DNA technology and is proof positive that if DNA samples are properly collected and stored, they can remain useful for decades.

On April 8, 1987, police executed a search warrant on the premises of one of the suspects, Gary Ridgeway. After obtaining evidence items from his house they requested that he undergo a polygraph, but Ridgeway refused. They then asked for a saliva sample and Ridgeway complied by biting on a small, square surgical gauze.

Unfortunately, the semen samples taken from some of the victims were too small for the then available testing procedures. Using them would have consumed the entire sample, and if no match was found, there would be no crime scene material remaining if another suspect was later identified. So, the samples, as well as Ridgeway’s saliva, were stored.

In the mid-1990s, DNA testing made a quantum leap when the combination of STR and PCR analysis appeared. This new technique allowed for testing very small samples and by 2001 it had become a proven and widely available technique.

In that year, the lab tested Ridgeway’s saliva sample, obtained in 1987, with semen samples taken from Opal Mills, Marcia Chapman, and Carol Christensen, all killed in 1982 or 1983. Using the new PCR/STR technique, the samples were amplified and compared. A match was made. Gary Ridgeway was arrested and charged with four of the Green River killings. The case took a dramatic and controversial turn on November 5, 2003, when Ridgeway pleaded guilty to 48 murders in exchange for a sentence of life without the possibility of parole, thus sparing himself a possible death sentence. Many involved in the case felt that Ridgeway’s victim list was much longer.

Now a new victim might have turned up. A skull was found in a ravine near Auburn, 25 miles south of Seattle, an area where the remains of Marie Malvar, another Ridgeway victim, were also found. Dental records revealed the skull was that of Rebecca Marrero who disappeared in 1982. Many involved in the case felt that Marrero was probably a victim of The Green River Killer, but Ridgeway could never supply enough information to prove that one way or the other.

Since Rebecca Marrero was not included in the original plea bargain, will we see Ridgeway charged and tried for her murder? Could he get the death penalty he avoided in 2003 after all? One can hope. We’ll see.

 

Tooth C-14 and the Age of a Corpse

Identifying unknown corpses is one of the most difficult things that the forensic pathologist and the forensic anthropologist must do. This is particularly true in situations of mass disaster where there are so many bodies to deal with or in circumstances where the body is severely decayed and there is little left to deal with but bones. The size, the sex, and the age of the skeletal remains narrow the possible identities. If the skeleton is intact, the size and the sex of the victim is usually easily ascertained but the exact age of the person is more difficult.

If the remains are those of a child it is usually easier since the development of the bones and teeth follow a pattern that is recognizable and more or less predictable. But once someone reaches adulthood this becomes more problematic. The teeth are often the best bet but once the wisdom teeth have completely erupted it is difficult to ascertain age. Hard to distinguish the skeletal remains of a 20 year old from a 35 year old.

Enter carbon-14. Carbon-14 is the radioactive isotope of carbon and is present in the residual of all organic materials. It has not been a useful forensic tool simply because it is too blunt and can only narrow down the age of the carbonaceous material to a century or so. So it is very good for determining if something is 500 years old or 5000 years old but not much help with a more recently deceased unidentified corpse.

A new technique has appeared that shows promise. A Swedish research team has begun looking at carbon 14 in tooth enamel and have found that it is highly accurate in determining the year of birth in anyone under 50 or 60 years of age. This technique uses the carbon-14 that was released into the atmosphere during the nuclear testing that was so common during the 1950s and 1960s. It’ll be interesting to follow this new technique and see if it really pans out to be as useful as hoped.

 

Dental X-Rays and Age Determination

I got a heads up about this interesting case from my friend Julie Kramer.

It seems that Mahdi Ali will have to visit the dentist and get some x-rays done. Not because he has any dental problems but because he is accused of killing three men during a Minneapolis convenience store robbery this past January. He and his friend Ahmed Ali apparently entered the Seward Market one evening, guns in hand. Mahdi forced the two men there to lie on the floor, all this taking place in front of the store’s security camera. While his friend was near the rear of the store attempting to rob someone else, Mahdi shot the two men and a third man who walked in the door. He is now charged with three counts of first-degree murder.

His defense attorneys claim that Mahdi Ali was only 15 at the time of the shooting and not 16 as was previously documented. They state that he was born on August 25, 1995 in Kenya and that this would’ve made him only 15 at the time to the shootings. This is critical since if he were only 15 he will be tried as a juvenile, but if he was 16, he will be tried as an adult and if convicted will be subject to a sentence of life without the possibility of parole. Big stakes.

So Mahdi will trot off to the dentist for dental x-rays to help determine his age. But there are a few problems with this. Yes both our deciduous (temporary or juvenile) teeth and our permanent teeth do tend to develop in a known and fairly predictable pattern. Our various types of teeth appear at certain ages and are lost as permanent teeth develop on their own timeline. Taking dental x-rays in this teenage group can often help determine the age of the person. Here’s the rub — it’s not all that accurate.

If you just look at the age at which the eruption of wisdom teeth occurs, it can vary by as much as five years. Some people get their wisdom teeth early and others see them late. We’re all different. In this case we’re looking at only a few months that would straddle Mahdi’s 15th and 16th years. It will be interesting to see what the experts say in this case and how accurate they will attempt to be. The bottom line is that determining whether someone’s age is 15 years and 10 months versus 16 years and three months is almost impossible. Stay tuned.

 
 

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