TEETH IN FORENSICS Desiré Brits School of Anatomical Sciences Room 2B07

Overview FORENSIC DENTISTRY Human identification Bite mark analysis Comparative identification Postmortem dental profiling Dental records Forensic anthropology Age Race Sex FOI Age Race Sex FOI

Forensic dentistry Major role of teeth in forensic dentistry – Human identification – Bite mark analysis Why study teeth – Most durable structure in the human body – Enamel is one of the hardest biological substances – Easily recognized, thus routinely recovered

Human identification COMPARATIVE IDENTIFICATION Establish if deceased remains and antemortem records represent same individual Compare postmortem dental remains with antemortem dental records (written notes, casts, radiographs) POSTMORTEM DENTAL PROFILING Antemortem dental records are unavailable No clues as to the identification of the deceased Compile a postmortem dental profile

Comparative identification Compare – Similarities – Discrepancies Explainable Unexplainable Numerous and complex dental treatments = easier identified

Comparative identification Conclusions that can be made include: – Positive identification Antemortem and postmortem = sufficient data match – Possible identification Antemortem and postmortem data = consisted features – Insufficient evidence Insufficient information – Exclusion Antemortem and postmortem = inconsistent

Dental records Developing countries – Unemployed individuals No dental care – Dental care = expensive – No access to facilities No dental records – Migrating workers International (local) – No dental records – Illegal immigrants No dental records – No continuous care Outdated records – Visit various dental facilities

Postmortem dental profiling Provide information: – Age – Ancestry – Sex – Factors of individualization Trauma – Tooth loss Dental pathology – Dietary habits » Socio-economic status Dental variation Dental treatment Dental modification / mutilation Habitual behaviours and/ occupation

Age estimation Mammals – Two sets of teeth Deciduous (or milk teeth) – Deciduous dental formula 2:1:0:2 = 20 Permanent teeth – Adult dental formula2:1:2:3 = 32 The development and eruption is fairly consistent Particularly in immature individuals Tooth formation begins in utero for: – Deciduous teeth – First permanent molar teeth Rest of the dentition – Develops after birth

Population affinity Race assessment from teeth are not easy! Not race related: – Root numbers – Congenital absence of third molars Asian dental complex – Shovel shaped incisors – Shorter roots – More occlusal enamel pearl in premolars – Frequently fused molar roots – Extra distolingual root on 1 st and 3 rd molars

Population affinity European dental complex – High frequencies of Carabelli’s cusp An extra cuspid on the mesiolingual surface of upper molars African dental complex – First mandibular molar 5-cusped with a Y-shaped groove – 4 th molars!

Sex determination Sexual dimorphism in dentition is variable – Sexing teeth alone = risky Discriminant function analysis – Accuracies between % ♀ teeth = smaller – Mesio-distal diameter Misclassification more common in males

FACTORS OF INDIVIDUALIZATION Features unique to an individual – Reduces population pool – Positive identification TRAUMA – Motor vehicle accidents – Pedestrian accidents – Fights – Antemortem tooth loss

FACTORS OF INDIVIDUALIZATION DENTAL PATHOLOGY – Dental caries – Abscess – Periodontal disease – Enamel hypoplasia  Socioeconomic stature  Dietary habits

FACTORS OF INDIVIDUALIZATION DENTAL VARIATION – Abnormal tooth number Hyperdontia Hypodontia – Abnormal tooth size Macrodontic Microdontic – Dental crowding – Impacted teeth

FACTORS OF INDIVIDUALIZATION DENTAL TREATMENTS – Dental crown – Dental bridge – Braces

FACTORS OF INDIVIDUALISATION DENTAL MODIFICATION Old practice – Rare Very noticeable – Groups/tribes association – Categories: Filing Chipping Extraction Decoration with inlays Practice of dental decoration arose in the Preclassic – Persons 15 yrs and older Filling – Mainly in females Incrustation – Mainly in men

tooth extraction South African modification: – Tooth extraction Some or all incisors – 2 nd decade of life – Male and female – “Passion gap” “CAPE FLATS SMILE” – Gang sign – Early 1980’s

Dental modification Modern South African modification – Dental inlays – Upper central incisors Middle class individuals HABIT OR OCCUPATION – Pipe-smoker’s wear M Steyn, EN L’Abbé, M Loots; 2004

Bite mark analysis

Summary Human identification – Comparative identification Dental records – Postmortem profiling Sex determination Race determination Age estimation Factors of individualization Suspect “identification” – Bite mark analysis