Introduction to Forensic Odontology

Question 1

6 main areas forensic dentists are involved in

Answer 1

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

Question 2

4 biological ways to identify people

Answer 2

FFDD (think Forensic Dentists)
-frontal sinuses
fingerprints
DNA
dental

Question 3

6 reasons teeth are good for identification

Answer 3

• biologically inert (eg immersed in fire/ water)
• restorations/ prostheses unique to individuals
• not just 1 tooth, whole dentition
• protected in oral cavity
• malocclusions and anomolies between individuals
• ANTE-MORTEM RECORDS of peoples fillings, radiographs etc

Question 4

technique for ageing adult skeleton

Answer 4

non-synovial joints eg pubic symphysis (secondary cartilagenous joint)

Question 5

use of skull in human identification

Answer 5

age: ossification of sutures BUT v unreliable
- male/ female
- race (caucasoid, negroid, mongoloid)

Question 6

how are teeth used for foetal ageing

Answer 6

fusion of the mandibular symphysis (fully fuses at 7-8 months), development of teeth

Question 7

how are teeth used for estimating longevity after birth

Answer 7

neonatal line- forms during birth, so any normal enamel/ dentine inside this shows the foetus was alive after birth

Question 8

how are teeth used for ageing before 20yo HIME

Answer 8

sequence of HIME
Histological pre-mineralisation/ mineralisation
Incremental formation of enamel/ dentine
Mineralisation sequence (radiographic eg DPT ageing/ direct observation)
Emergence/ eruption in to oral cavity

Question 9

how are teeth used for ageing post 20yo

Answer 9

• closure of apices of 3rd molars ~21yo
• wear and tear
• root dentine translucency (more translucent with age, filled with intratubular dentine)

Question 10

years range within which accuracy of ageing is limited

a. attrition methods
b. aspartic acid racemization

Answer 10

a. attrition methods: +/-15yrs

b. aspartic acid racemization: +/-3yrs

Question 11

gustafson 1966 6 measurements of regressive changes in adult teeth

Answer 11

• occlusal attrition
• coronal secondary dentine formation
• loss of periodontal attachment
• apical cementum apposition
• apical resorption (least accurate)
• root dentine translucency

Question 12

when are radiographs mostly used for ageing 2

Answer 12

• when material must be left intact:
• -living subjects
• -fragile remains eg incineration
• -anthropological remains
• assess secondary dentine deposition by measuring pulpal area

Question 13

what is done to stop magnification errors from radiography

Answer 13

measurements done in ratios of root to pulp

Question 14

explain amino acid racemisation (AAR)

Answer 14

• amino acids in L form until tissue turnover stops (with age) –> D form
• -> measure D/L ratio gives tooth age

Question 15

2 amino acids used in AAR

Answer 15

aspartic acid

leucine

Question 16

5disadvantages of amino acid racemisation

Answer 16

• temp dependent
• few labs with calibration curves
• only tested on recent material
• can’t be applied to burnt material
• uncertain effects of water, soil, time

Question 17

enamel or dentine proteins thought to be more resistant to post mortem changes

Answer 17

enamel proteins

Question 18

explain C14 incorporation

Answer 18

cold war (1953-1963) C14 incorporated in to enamel –> compare C14 in teeth with levels in atmosphere at time of birth –> determine place/ year of birth