Analyzing Dental Impressions at Home

By: Samantha Ribble

Now through September 6, the Museum of Science and Industry (MOSI) is hosting to the traveling exhibit CSI: The Experience. This interactive exhibit turns guests into crime solvers as they investigate the scene, collect and analyze evidence, and bring the criminal to justice. With three different crime scenes to choose from and a high-tech laboratory, visitors are sure to walk away with a greater knowledge of what it takes to be a CSI.

Kids can be investigators in their own homes by analyzing evidence of the mouth – dental impressions.

Eighty percent of the time, teeth impressions are used to identify unknown victims. When fingerprints cannot be recovered and DNA testing is not possible, the teeth can give investigators a place to start. Since the enamel on your teeth is one of the hardest substances in your body, teeth are often well preserved.

Humans get two sets of teeth in their lifetime. By age three, children have a complete set of 20 baby teeth. Permanent teeth begin developing around the age of six and, over a span of 15 years, continue to cultivate until all 32 adult teeth are in place.

Teeth can reveal age by looking closely at level of development and wear. Dental records help investigators match a person’s mouth to a name.

All you need to get your young ones started on their first investigation are a few household items: scissors, Styrofoam plate, marking pen, and a thick piece of cheese or chocolate. Have the investigator leave the room and one of the suspects take a bite out of the cheese/chocolate. See if you can identify the person who took the bite by comparing impressions.

1. Divide the Styrofoam plate into six equal wedges. Cut the wedges.
2. Take two of the wedges and stack them together. Cut off 1 inch from the pointed end of the wedges.
3. Place the two wedges into your mouth as far as possible.
4. Bite down on the wedges firmly and then remove them.
5. Label the top and bottom wedges Top Teeth and Bottom Teeth.

Have your little investigator study the teeth impressions, make the comparisons, and figure out who bit it.

A Brief History of Dental Impressions:

The first published account where a suspect was convicted using bite mark evidence occurred in 1954 in the case of Doyle vs. State.

A grocery store in Aspermont, TX was broken into on the night of December 15, 1954. The burglar had stolen 13 silver dollars, small change, two bottles of whiskey, and decided to snack on some of the meats and cheeses behind the meat counter.

Once apprehended, the suspect was asked to bite into another piece of cheese. After a dentist compared the freshly bitten cheese slice and one recovered at the scene, the suspect was convicted of his crime.