Odontology

Forensic Dentistry: The application of dental

knowledge to civil and criminal matters

What training is required to be a forensic odontologist

• Dental degree –

• Course(s) in forensic odontology offered through an approved program such as AAFS and ABFD

• Usually only part time

Bite marks

• Human bite marks are primarily found on victims of sex crimes

• They may also be found on victims of vicious fights and child abuse

• They may be found on perpetrators as the victim tries to defend himself/herself

How are teeth used to ID a persons?

• Teeth resist destruction and decomposition

• Teeth are unique to the individual• Information about the teeth has been

recorded prior to death in most cases• Dental identification satisfies the

Daubert rule for Physical Evidence

Teeth are unique to the individual. Items to look for:

• Restorations – amalgam, gold, resin, porcelain• Fillings – location, size, and shape• Gums• Root canals• Missing teeth• Unerupted teeth• Patterns of arrangement• Appliances

Fun fact!

• THE FIRST American use of forensic dentistry to make a positive ID was in the case of Dr. Joseph Warren. He was thought to have died in the Battle of Bunker Hill. Skeletal remains were found with a dental implant. The implant was made of silver and was taken to the silversmith who was thought to have made it.

• This man admitted to having personally crafted it for Dr. Warren

• The silversmith’s name was Paul Revere

The Primary Function of Odontology

• To have a positive human identification through the comparison of unique dental characteristics

Universal Numbering System

• Tooth number 1 is the tooth farthest back on the right side of your mouth in the upper (maxillary) jaw.

• Numbering continues along your upper teeth toward the front and across to the tooth farthest back on the top left side (which is number 16).

• The numbers continue by dropping down to the lower (mandibular) jaw.  Number 17 is the tooth farthest back on the left side of your mouth on the bottom.

• Numbering continues again toward the front and across to the tooth farthest back on the bottom right side of your mouth (which is number 32).

• In this system, the teeth that should be there are numbered.  If you are missing your wisdom teeth, your first number will be 2 instead of 1, acknowledging the missing tooth.  If you've had teeth removed or teeth are missing, the missing teeth will be numbered as well.

                                                                        

Tooth Numbering

RIGHTLEFT

DENTAL FORMULAE

• Upper Ex: ICPM: 3142 Lower: Ex: ICPM: 3143• Permanent Teeth in Humans• 2 1 2 3

2 1 2 3 = 16 • Tooth Eruption Deciduous Permanent• Incisors 6 - 10 months 7 - 8 years• Canine 16 - 20 months 11 years• Premolars 11 - 13 years• Molars 10 - 24 months 6 - 25 years

Bite marks

• Take a styrofoam plate and cut the edges off• Take the remaining circle and fold in half. • Cut the folded circle in half and give one part to

your partner. • Take the folded plate and put it in your mouth and

bite down hard. • Open the plate up and you will have your bite

mark. • Take a piece of wax paper, and draw your bite

mark with permanent marker. • Turn in

Making of teeth cast

• Each student is to bite down on a ball of white Model Magic (no flavor)

• Label the top and bottom with a permanent marker.

• Label the plastic cup that the Model Magic is put in with your name.

Making Teeth Cast

• Take the dried Model Magic Impression • Take a plastic cup and put about 3 tablespoons of

plaster of paris. • Add water slowly until a thick past is created. • Cover the top of the impression with Plaster of Paris

and place in a lower cup to hold so it can dry. • Do the bottom impression the next day. • Check the cast after 2 days to make sure that it is

hard.

Tooth Surfaces – Mesial Surface

That surface or side of a tooth which touches the tooth in front of it is called the mesial surface. The mesial surface faces toward the midline or front of the mouth.

Distal Surface

That surface or side of a tooth which touches the tooth in back of it is called the distal surface. The distal surface is the side farthest away from the midline or front of the mouth.

Occlusal Surface

All posterior teeth have broad, flat surfaces which are used to grind food. These chewing surfaces of posterior teeth are called occlusal surfaces.

Incisal Edge

• All anterior teeth have thin cutting edges used to tear food. The cutting, or biting edges of anterior teeth are too thin to be considered surfaces. Therefore, they are called incisal edges.

Lingual Surface

• The surface of a tooth which faces the tongue is called the lingual surface. All the anterior and posterior teeth have lingual surfaces.

Buccal Surface

• The surface of a posterior tooth which faces the cheeks is called the buccal surface. The term buccal surface is used only in connection with the posterior teeth (premolars and molars).

Labial Surface

• The surface of an anterior tooth which faces the lips is called the labial surface. The term labial surface is used only in reference to the anterior teeth.

Facial Surface

• The term facial may be substituted for either the term buccal or labial. The facial surface applies to both the anterior and posterior teeth. It is the surface which is towards the lips or cheeks.

REMEMBER

*Buccal - surface of posterior teeth facing cheeks

*Labial - surface of anterior teeth facing lips

*Facial - surface facing either lips or cheeks

You try

• http://www.forensicdentistryonline.org/Fire_folder/case1.htm

Photography

• Be sure to take good photographs of the bite mark as soon as you can.

• Take pictures with and without a scale as well as orientation shots.

• Bracket your exposures

• Vary the angle of the

lighting

Casting

• Forensic odontologists will make a mold and then a cast of the suspect’s teeth

• They will also make a mold of the bite marks if possible

• Then they will compare the two. An overlay may be made from the cast to compare to a photo

The most famous bite mark case of the 20th century???

• Who was it?

• Ted Bundy