Dental Evidence in Forensic Identification – An Overview, Methodology and Present Status
DENTAL EVIDENCE IN FORENSIC IDENTIFICATION
Authors: Kewal Krishan, Tanuj Kanchan, Arun K. Garg
Affiliations:
Department of Anthropology, Panjab University, Chandigarh, India
Department of Forensic Medicine, Kasturba Medical College, Mangalore (A Constituent Institute of Manipal University), India
Department of Orthodontics, Dr. Harvansh Singh Judge Institute of Dental Sciences and Hospital, Panjab University, Chandigarh, India
Abstract:
Forensic odontology involves the use of dental and oral structures for legal identification.
Techniques in forensic odontology aid in identifying human remains following
terrorist attacks,
accidents (airplane, train, road),
mass murders,
natural disasters (tsunamis, earthquakes, floods) - known as Disaster Victim Identification (DVI).
Dental structures are resilient, resistant to decomposition, and high temperatures, making them crucial for identification.
Identification is based on the uniqueness of each individual’s oral cavity—it is impossible for two oral cavities to be the same.
Dental features considered for identification include:
tooth morphology,
size and shape variations,
restorations,
pathologies,
missing teeth,
wear patterns,
crowding,
tooth color,
rotations, and
dental anomalies.
In the absence of ante-mortem dental records, teeth can provide information to determine:
age,
sex,
race/ethnicity,
habits, and
occupations.
The overview discusses the utility of dental evidence in forensic identification and its limitations.
Keywords:
Age estimation,
Bite marks,
Dental anomalies,
Forensic odontology,
Sex and race determination from teeth,
Wrongful convictions.
INTRODUCTION
Definition:
“Forensic odontology is a branch of dentistry which deals with the proper handling and examination of dental evidence and the proper evaluation and presentation of dental findings in the interest of justice.” [1]
Scope and Importance:
Forensic odontology is now recognized as a specialty within forensic sciences.
Integral to international forensic educational organizations like:
American Academy of Forensic Sciences (AAFS)
International Association of Identification (IAI)
Primary utility in identifying human remains amidst highly damaged bodies in disaster scenarios (e.g., bomb blasts, airplane crashes) where other identification methods (fingerprints, facial features) are compromised.
Teeth Characteristics:
Adult human dentition includes:
incisors,
canines,
premolars, and
molars with unique arrangements and characteristics.
Identification features include:
dental pathology,
restorations, and
dental anomalies.
Goals of the Review:
Highlight the importance of teeth in the identification process
Utility in biological profile estimation (age, sex, race)
Present status of dental evidence in forensics.
AGE DETERMINATION
Significance:
Dental maturity is crucial in estimating ages, especially in children and adolescents.
Methods:
Erupted teeth and their sequence help gauge age.
Radiographic methods enhance accuracy in determining mineralization stages.
Comparison of Estimates:
Dental mineralization is less susceptible to variations in nutrition and endocrine status compared to bone mineralization.
Techniques for Adults:
Gustafson Method (1950):
Utilizes regressive changes in teeth to estimate age based on features:
Occlusal attrition,
Coronal secondary dentine formation,
Loss of periodontal attachment,
Cementum apposition,
Apical resorption,
Root transparency.
Johnson's Improvements:
Expanded upon Gustafson’s methods, widely used in forensic practice.
Kvaal Method:
Measures pulp size in periapical radiographs, correlated with sex.
For Children and Adolescents:
Eruption status of teeth gives indication of age.
SEX DETERMINATION
Overview:
Determining sex from teeth is not definitive, yet can provide clues.
Techniques:
Odontometrics: Measurement techniques relying on size differences in teeth between sexes.
Mesio-distal and bucco-lingual dimensions are significant.
Linear and Diagonal Measurements:
Linear: Mesio-distal and bucco-lingual dimensions.
Diagonal: For crowded or rotated teeth.
Dental Indices:
Indices derived from linear measurements assess sexual dimorphism (e.g., Incisor Index, Mandibular-Canine Index, Crown Index).
Findings:
Mandibular canines show greater sexual dimorphism than maxillary canines.
Overall accuracy of odontometric sex determination is approximately 72%.
Non-Metric Features:
Canine distal accessory ridge correlates with sex.
Advanced Techniques:
DNA extraction techniques (PCR) utilized to assess sex using enamel proteins like Amelogenin, distinct patterns between sexes.
RACE DETERMINATION, OCCUPATION/HABITS, AND CULTURAL PRACTICES
Overview:
Morphological dental features indicate ethnic variations, assisting in distinguishing ancestry.
Identifying Features:
Characteristics aiding in ethnicity determination include:
shoveling of upper incisors (common in Mongoloids),
taurodontism,
Carabelli's cusp,
chisel-shaped incisors,
peg-shaped teeth.
Influence of Occupation:
Certain habits arise from occupational practices:
Needle holding (dressmakers),
Nail holding (cobblers, carpenters),
Pencil and pen biting,
Pipe and cigarette smoking.
Restoration Methods:
Unique methods of restorations convey ethnicity and socio-economic status.
COMPARISON OF DENTAL RECORDS AND ANOMALIES IN THE TEETH
Role of Forensic Odontologists:
Assist law enforcement in presenting dental evidence from crime or mass fatality scenes.
Compare dental evidence against ante-mortem records for identification.
Comparative Techniques:
Use dental radiographs and available dental records for comparison.
Assess features for individualizing characteristics:
dental fillings,
extractions,
crowding,
diastema,
missing teeth,
anomalous root configurations.
Types of Dental Anomalies:
Anomalies include:
microdontia (smaller teeth),
macrodontia (larger teeth),
anodontia (absence of teeth),
hyperdontia (additional teeth).
Eruption Disturbances:
Impactions & Ectopic Eruptions: Teeth failing to erupt due to obstruction.
Shape Disturbances: E.g., dilaceration and flexion, taurodontism.
BITE MARKS
Uniqueness:
Bite marks are distinctive and considered highly individualistic, crucial for forensic examination.
Types of Bite Mark Evidence:
Found on victims' skin or on consumables (hard foods).
Bite marks assessed through casts or photographs for comparisons.
PALATAL RUGAE
Definition:
Irregular folds on the palate, unique to individuals, stable throughout life but subject to size changes due to palate growth.
Importance:
Aid in identifying edentulous individuals and can survive destruction from fire or cases of decomposition.
QUESTIONABLE DENTAL EVIDENCE AND WRONGFUL CONVICTIONS
Issues with Bite Mark Evidence:
Considered unreliable due to flawed reasoning and lack of statistical validation.
Cases of Wrongful Conviction:
Documented instances in which DNA disproved associations made from bite marks.
Calls for standardized regulations in forensic practices initiated by US Department of Justice and the National Institute of Standards and Technology (NIST).
CONCLUSION AND PRESENT STATUS OF DENTAL EVIDENCE
Current Utility of Dental Evidence:
Despite advances such as DNA profiling, dental records play a significant role in identifying deceased individuals in mass fatalities.
In their absence, dental evidence can assist in estimating biological profiles (age, sex, race).
Caution advised due to population-specific variations in dental traits.
Promotion of Forensic Odontology:
Urgent need to promote this specialty through education and advisory in dental sciences for forensic casework and investigations.
CONFLICT OF INTEREST
Authors' Declaration:
No conflict of interest reported.
ACKNOWLEDGEMENTS
Gratitude:
Authors thank their respective universities for supporting research publications in reputable international journals.