1. Teeth, Shoe, Tire, and Tool Marks
Impressions
Teeth, Shoe, Tire, and Tool Marks

2. Classifying Characteristics
Class Characteristics- Evidence associated only with a common source
Examples- type of gun (handgun vs. rifle), brand of shoe (Nike vs. Adidas), manufacturer of a tool (Craftsman vs. Mac)
Individual Characteristics- Evidence that can connect a crime scene sample to a standard reference sample
Examples- striation marks, wear and tear, chips or gauges

3. Teeth Marks Used in homicide and rape cases
Dental records are used to identify remains
Almost everyone has a dental record, unlike fingerprint records

4. Types of Teeth Incisor Cuspid/Canine Bicuspids/Premolars Molars
Rip and tear
Cuspid/Canine
Tearing
Bicuspids/Premolars
Grinding
Molars
Grinding and Crushing
Third Molars are Wisdom Teeth

5. Baby Teeth Temporary (Deciduous) teeth Also called Milk teeth
Only 20 teeth
Fall out or dissolve as permanent teeth move into place

6. Adult Teeth Average human has 32 adult teeth
Teeth are numbered from lower left (1) to upper right (32)
Orientation and position of teeth make teeth unique
Dental work will help to make teeth unique

7. Case Studies-Dental Records
Airplane crash: dental records used to identify victims
Oklahoma Bombing: 25% of dead identified by teeth
Jeffery Dahmer: eleven of his seventeen victims were identified by dental remains

8. Case Studies-Bite Marks
Ted Bundy- Was convicted of several murders in Florida because of his tendency to bite his victim. This was the only evidence that could place him at the scene of the crime.

9. Footprints and Tire prints
Two types of impressions
Indentations: made in soft material - wet dirt, clay, snow
Residue: from surface of object - blood or dirt
Chemicals can be added to footprint evidence to develop footprints made in blood

10. Preservation of Impression
Original is best
Photograph all impressions in case of damage
Handprint (sticky material) or Pathfinder (electrostatic) used to lift residue impressions
Casting used for indentations

11. Analysis of Impression
Similar to fingerprint evidence in collection and analysis
Not based on identifying the brand name but rather matching imperfections from the suspects item to the print from the scene
There are data bases for tire and shoe prints to identify name brands or manufacturers

12. Examples

13. Tool Marks
Any impression, cut, gouge or abrasion caused by a tool coming into contact with another object
Usually found at a burglary scene
Wear and use produce discernable nicks and breaks that can be specifically identified

14. Collection of Tool Marks
Difficult to reproduce a tool mark in the lab
Examination would require several tests of the tool at different angles and pressures
If removal is impossible - photos and cast should be used

15. Analysis of Tool Marks
An examiner should never try to fit the tool back into the tool mark - this will alter the evidence
Trace evidence may also be present on the tool or in the tool mark - blood, paint, etc.