Forensics

Question 1

What do forensic dentists do?

Answer 1

Provide opinions that are considered valid in a coroners court, requires proper handling, examination and evaluation of dental evidence

Question 2

What are the six main areas of practice for forensic dentists?

Answer 2

• identification of found human remains
• indentification in mass fatalities
• assessment of bite mark injuries
• assessment of child abuse and of adults and elderly
• civil cases involving malpractice
• age estimation

Question 3

Why identify the deceased?

Answer 3

• it’s the last dignified thing you can do for the person
• allows correct body to be released to relatives
• allows relatives to bring closure
• wills, insurance, pensions and other benefits to be paid
• cultural reasons (allow burial and remarriage)

Question 4

Why are teeth good for identification?

Answer 4

• biologically inert
• protected within the oral cavity
• malocclusions and anomalies
• antemortem records available: written record of restorations done (more difficult if none), dental chart, radiographs, study models

Question 5

Why age the deceased?

Answer 5

Identification, grouping in cases of multiple unidentified bodies, see if dead baby was alive at birth

Question 6

Why age the living?

Answer 6

If still a child or not, not accurate, within a few months not an exact age!

Question 7

How can we age people (3)?

Answer 7

Appearance, features of skeleton, teeth

Question 8

Why is judging by appearance not very good?

Answer 8

Subject to high degree of false positives and negatives, difficult for relatives to identify people and plastic surgery etc can change how old you look

Question 9

How can we age looking at features of the skeleton?

Answer 9

• non synovial joints -> Surface compared to charts for levels of wear and tear related to broad age range, most commonly used pubic symphysis (secondary cartilaginous joint)
• cranial sutures -> assess degree of ossification and shape also determine race into 3 groups (Caucasoid, negroid or monogloid) and sex

Question 10

How do we age using teeth:

Answer 10

• foetal ageing
• neonatal line
• developmental and mineralisation dates (before 6 months)
• erupting dates and root development (before 20 y/o)
• tooth surface loss

Question 11

What methods can assess tooth surface loss and to what accuracy?

Answer 11

Attrition +/- 15 yrs

Aspartic acid racemization +/- 3 yrs

Question 12

What other factors can assess tooth surface loss?

Answer 12

• root dentine translucency
• occlusal attrition
• coronal secondary dentine (radiograph, toot area: pulp area)
• loss of periodontal attachment
• apical cementum apposition
• apical resorption

Question 13

What is amino acid racemitization?

Answer 13

In nature amino acids are in L form, once metabolic turnover stops they are slowly converted to D form, D:L ratio indicates age
N.b. Especially useful in dentine because no fast turnover but less successful in enamel as less proteins

Question 14

What are the issues with amino acid racemitisation?

Answer 14

• strongly temp dependent
• few labs worldwide with calibration curves
• effects of water, soil and time currently unknown
• would be better to use enamel as more resistant to post mortem changes

Question 15

What is C14 incorporation ageing technique?

Answer 15

“Bomb pulses” in Cold War (1953-1963) changes levels of c14 in atmosphere, incorporated into enamel at birth, level in atmosphere at time compared to level I. Teeth to determine year of birth and geographical location

Question 16

What are the problems with post mortem ageing?

Answer 16

• lack of consensus or uniformity of procedures used across labs
• reference samples only available for some populations
• estimate only
• older a person is the larger the discrepancy between biological and chronological age