1. Bite Mark and Teeth Impression Evidence

2. How do forensics investigators use bite mark evidence?
Analyze bite marks for characteristics to identify victims or suspects or exclude others.
Marks can be left on a victim’s skin or other objects, such as Styrofoam cups, gum, or foods.
Saliva or blood may be left behind that can be tested for DNA.
Dental records including x-rays can also provide useful information, especially when attempting to identify a victim.

3. Individual Evidence
Bite marks, like fingerprints, are unique to an individual.
Forensic odontologists will make a cast or take pictures of the bite marks

4. Bite Mark Evidence Collection
Photograph the area with a ruler near the injury (in color and B&W).
Area is swabbed for traces of saliva (may contain DNA)
Area is swabbed for microorganisms
Impressions of the bite mark are made

5. Measurements Investigators take careful measurements of the bite marks
These measurements can later be compared to a victim or suspect

6. Development of a child’s teeth can help estimate the age of a young victim.

8. A human bite mark will be elliptical or circular and
Will display the specific characteristics of the teeth

9. The dark markings identify specific characteristics.
Fillings, caps, chips, evidence of dental work

10. Types of Bites
clear impression means that there was significant pressure;
Obvious bite signifies medium pressure
noticeable impression means that the biter used violent pressure to bite down.

11. Clear Obvious noticeable

13. Food can be evidence
Investigators can compare the bite patterns on the food to a known sample.

14. Matching mold to bite mark

15. Analysis of Bite Mark

16. Class Characteristics
Shape of arch
Tooth alignment
Thickness
Width
Spacing
Missing teeth
Other unique
features

17. Terminology Positive identification-exact match
Possible identification-consistencies exist, but not enough to make an exact match
Insufficient evidence-not enough evidence to make a determination
Exclusion-does NOT match

18. Serial Killer Ted Bundy
Impressions being made of Bundy’s teeth.

19. Part 1: Make an Impression
1 – Fold the Styrofoam plate in half.
2 – Label one side MAXILLA and the other MANDIBLE.
3 – Gently bite down on the plate to leave your bite mark impression.
4 – Place a sheet of the plastic film over the impression and use a permanent marker to recreate the pattern to match that of your bite mark.
5 – Use a ruler to make the measurements shown and record in the table below along with any notes regarding unique characteristics you observe in the teeth.
Maxilla
Mandible
Depth
Maxilla
Width
Mandible