Forensic Odontology: Identifying Victims Through Dental Records

KEY TAKEAWAYS

• Forensic medicine, especially through autopsies, is crucial for identifying the deceased and determining the cause of death, providing detailed information in weapon-related deaths and disaster scenarios.,
• Forensic investigation/medicine applies to a variety of problems in medical science, including determining blood relationships, and mental illness and analysing evidence in violent crimes such as rape through techniques like DNA fingerprinting. 
• Dentists specialising in forensic odontology are crucial for identifying individuals through dental structures and analysing injuries, participating in crime scene investigations, and mass disaster victim identifications such as in “natural calamities” and cases of professional negligence or injury. 
• The admissibility of a forensic odontologist’s report in court depends on the expert's qualifications, the report’s scientific validity and its direct relevance to the case, after submitting all the necessary evidence it is purely on judge’s discretion “If the report that is submitted as evidence” could be allowed as “admissible” in the court of law.

INTRODUCTION

The term “forensic” originates from the Latin word which means “to the forum” or “to the court” (which indicates its legal connotations). Odontology on the other hand refers “to the study of teeth of a living being”. According to one of the intellectuals of forensic odontology Keiser–Nelison in 1970 defined forensic dentistry as “the branch of dentistry that in the interest of justice deals with the proper handling and examination of dental evidence and proper evaluation and presentation of dental finding”

Forensic odontology, also known as forensic dentistry, is a specialized branch of forensic science that applies dental knowledge and expertise to legal and criminal investigations. This field involves the examination, evaluation, and presentation of dental evidence in both civil and criminal cases, centuries back, “Dr Oscar Amodeo, often considered the father of forensic odontology”, Amodeo made some significant contributions to the field of forensic odontology such as his work on dental identification scenarios where many individuals lost their lives. 

Simply, teeth are unique to each person, and this makes them very useful in investigations. forensic odontologists use their knowledge to identify human remains, determine a person’s age, and sex and learn about their dental history and oral health, which can be crucial in solving cases. Forensic odontology is a branch of dentistry that uses dental science to provide legal evidence. It is crucial to identify victims whose bodies are mutilated, burned, decomposed, or involved in major disasters, including natural catastrophes, terrorist attacks, and industrial accidents. Forensic odontologists are often called to assist in identifying victims from events like plane crashes, explosions and chemical or nuclear incidents. 

In situations where traditional methods like fingerprinting or visual identification are not possible, forensic dentists step in to examine decomposed, burned or skeletal remains. Their tasks include diagnostics, monitoring, referrals, decontamination, infection control, evaluations, vaccinations, medications, testing, and additional medical care during major disasters. 

Tooth size is considered a key tool in forensic odontology, which helps precinct an individual’s sex, specific dental measurements, such as the incisor index, mandibular canine index (MCI), and crown index, reveal differences between male and female teeth. Studies have shown significant size differences in dental crowns between sexes with males typically having larger teeth, especially the mandibular canines, incisors, premolars and molars. The width of the dental crown and the combination of root lengths are also used to determine gender. Additionally, dental age is a reliable identification tool as dental maturity is not affected by nutrition or hormonal status. 

Dental implants are often the last part of the body to be destroyed after death, making them valuable for identifying individuals in major catastrophes or when bodies are severely decomposed. Dental records can also aid in identifying suspects in criminal investigations and medical cases. In many European and Western countries maintaining dental records are a legal requirement, however, in India the laws regarding dental record keeping are unclear, and awareness of this issue is poor. The primary purpose of maintaining dental records is to ensure quality patient care and follow-up. 

It is essential for practitioners to have a thorough understanding of dental record issues, as public awareness of legal matters related to healthcare is increasing along with incidences of insurance fraud. Given the growing awareness of these legal issues and the rise in insurance malpractice cases, comprehensive knowledge of dental record management is crucial for all practitioners. Under section 17-A of the Dentist Act, 1948, there are significant benefits for those who are proficient in record keeping, helping to maintain professional respect and dignity, the Indian Dental Association (IDA) recommends that practitioners keep records for up to five years to meet legal requirements and protect against medical negligence and complications.

Dental records are crucial for identifying individuals who cannot be recognized visually. The clinical practitioner must produce and maintain accurate dental records, including detailed documentation of a patient's medical history, diagnosis, treatment, physical examination, and management. This is essential for providing high-quality patient care and fulfilling legal obligations. Forensic odontology combines three disciplines:

• Anatomy 
• Pathology 
• Radiography. 

These three-study dental remains are for identification and investigation. Anatomy provides knowledge of dental structures and individual variations, giving us a clear understanding of what we are examining. Pathology offers insight into diseases or trauma that may have affected the teeth, aiding in the identification and revealing aspects of the individual's medical history, radiography, including X-rays and other imaging techniques, allows us to closely inspect these dental abnormalities, highlighting their unique features for identification purposes. 

HISTORICAL BACKGROUND OF FORENSIC ODONTOLOGY 

Law and Medicine have always been intertwined since ancient times, such as connected by religion or superstition. The Charaka Samhita, from around the seventh century B.C., established an elaborate code for training, duties, privileges and the social status of physicians, and provided detailed descriptions of poisons and their treatments. In the fourth century B.C., Manu, a king and lawgiver, outlined laws in the Manusmriti including punishments for various offences and recognition of mental incapacity due to intoxication, illness and age, between the fourth and third centuries B.C., the Arthashastra by Kautilya defined penal laws and regulated medical practice, with physicians being punished for negligence, therefore medical knowledge was applied to legal matters, including the examination of dead bodies in unnatural deaths and crimes like abortion, sexual offences, and kidnapping were punishable. 

Ancient records from countries like Egypt, Sumer, Babylon, India and China dating back to 3000-4000 B.C., also highlight the relationship between medicine and law. A Chinese “Materia Medica” from around 3000 B.C., detailed poisons, “Imhotep” a prominent figure in the 27th century B.C., enacted rules for medical practice in Egypt. The code of “Hammurabi” from around 2200 B.C., is the oldest known medico-legal code. The Rig Veda and other Vedas, from 3000 to 1000 B.C., mention crimes and their punishments, with physicians recognized as professionals. The Atharva Veda provides remedies for various conditions. 

The first medico-legal autopsy was performed in 1302 by Bartolomeo De Varignana in Bologna, Italy. In the 13th century, a manual was created in China to aid death investigations. George, bishop of Bamberg proclaimed a penal code in 1507 requiring medical evidence in certain cases. the Caroline Code of 1553 in Germany mandated expert medical testimony in cases of murder, wounding, poisoning and other crimes, recognizing that some homicides were not punishable under specific conditions such as mental incapacity.

One of the most significant works in legal medicine is “Questions Medicolegales” by Paulus Zacchias, published between 1621 and 1635, with additional volumes in 1666. Zacchias, the principal physician to Pope Innocent X and Alexander VII, is considered the Father of Legal Medicine and Forensic Psychiatry. He argued that physicians should have exclusive competence in diagnosing mental disorders and provided a classification of these disorders relevant to legal issues. 

METHODS USED IN FORENSIC ODONTOLOGY TO IDENTIFY VICTIMS OF CRIME AND DISASTERS

Forensic odontology has been considered one of the most important parts of investigation in the realm of law which helps in identifying victims of sexual assault and child abuse or victims of natural hazards. Dentists maintain detailed records that are essential for identifying individuals. Human dental anatomy, which includes incisors, canines, premolars, and molars, varies in shape, size, restorations, rotations, missing or broken teeth, pathologies and colour due to various exogenous (this refers to external influences or factors that come outside the body, such as fillings or staining) and endogenous factors (this refers to internal influence or factors that originate from within the body such as genetic tooth development, natural wear and tear over time). These unique dental characteristics provide a distinct identity to each individual. 

1.  Identification of Species – Identifying a tooth from a crime scene involves carefully comparing accurate “Antemortem (pre-death) and Postmortem (after-death) data”. This process includes recovering materials from the scene, preparing and reconstructing the tooth, examining and documenting it at the mortuary, collecting and transcribing antemortem dental records, and communicating with dentists, sorting and comparing antemortem and postmortem data is then crucial for accurate identification.  In mass disaster victim identification, “Radiographs” are particularly useful. They offer advantages over charting because they reveal distinctive configurations of “Bony” structures in the jaw, tooth, roots and nearby sinuses, which are unique to each individual. In cases involving decomposed or charred bodies, the jaws may be split down the midline to obtain better lateral films for comparison with antemortem radiographs.
2. Gender Determination – Determining the sex of an unknown individual is crucial in identification. “Craniofacial morphology”, particularly features of the skull and mandible, is highly effective, with a success rate of 96% in individual identification. Tooth size, measured by mesiodistal and buccolingual dimensions, is also commonly used for gender determination in studies. These dimensions are typically assessed using dental radiographs or advanced 3D imaging techniques. Moreover, certain dental features like the shape of incisors or canines can offer valuable clues about gender. Gender determination can also involve examining the presence of sex chromatic or bar bodies in dentin, which are influenced by the “Amelogenin enamel protein”, a sex-linked gene. By performing DNA profiling on oral tissues, even minute amounts of DNA in dental pulp can reveal the individual’s sex. In DNA analysis, the differentiation between males and females is possible due to the distinct sequences of the amelogenin gene. Males possess “non-identical” amelogenin genes (XY) with sequences of 106 and 112 base pairs, while females have two identical amelogenin genes (XX) with a single 106 base pair sequence. This genetic disparity enables accurate differentiation between male and female identifications. 
3. Race Determination – Humans have been categorized based on various dental characteristics that reflect the different ethnic backgrounds, for example, “Caucasoid” individuals often have a narrow “V” shaped dental arch, leading to crowding of teeth, “Mongoloid” and American Indian populations may exhibit “Posterior Concave upper incisor grooves”, Europeans individuals typically have flat lingual surfaces on their incisor teeth, while Japanese individuals may have ridges on the lingual surface of their incisors, Negroid individuals often have small and square molars. other dental traits, such as “shovelling, taurodontism, carabelli's cusp, hypocone, protostylid, and peg-shaped incisors”, are also used to determine ancestry. Additionally, dental restorations can provide clues about an individual’s ethnicity, as the type of dental treatment received may reflect their financial situation. Furthermore, teeth offer valuable evidence about an individual’s habits and occupation, providing insight into their lifestyle and daily activities.  
4. Bite Mark Analysis – According to Mac Donald, a bite mark is defined as a mark caused by the teeth either alone or in combination with other mouthparts. In human cases, bite marks are often associated with sex crimes due to their potential as forensic sciences. The distinctive patterns and characteristics of bite marks can help identify the perpetrator and provide crucial information for criminal investigation. However, it's essential to recognize that bite marks can also occur in other situations, such as self-defence or accidents, and should be carefully examined. 
5. Photographic Method – A bite mark is typically captured in a photograph by positioning two scales at a right angle to each other in the horizontal plane. Specialised mirrors are used to photograph all the teeth in either the upper or lower jaw in a single image. These photographs are tracings of the teeth and are then compared with known dental records. In some cases, the cutting edges of the front teeth are linked to create tracings of bite impressions using positive casts. These tracings are placed on clear sheets and overlapped with the photographs, or a negative picture of the teeth is placed on top of a positive picture of the bite. It's important to note that it is often easier to exclude potential matches than to positively identify them. Photographs are commonly taken at crime scenes, from victims, or from suspected individuals for accurate identification purposes. Additionally, photographs of bite marks from repeat offenders can be stored in dental databases for future reference. 
6. Computer Odontology – Advancements in computer technology have revolutionised forensic odontology, significantly enhancing the identification and analysis of dental evidence. Computer applications and database management systems have greatly improved the accuracy, speed, and efficiency of the identification process, for example, Automatic dental code matching (computer algorithms search for matches between bite marks and known dental codes), “Odontosearch (comparison of dental records is based on characteristics of missing persons), “Automatic dental identification system” (lists individual with matching dental code numbers), “3D bite mark analysis” (utilises three-dimensional technology to generate overlays, comparing bite marks with various pressures and deviations, this technique enables precise comparisons between antemortem and postmortem dental records), “Dental radiography” (computerised CT scans produce high-resolution images that assist in the identification process). In cases involving bite marks, immediate response by forensic dentists is crucial. Bite marks fade rapidly, both in living and deceased individuals, with their appearance changing within hours. Delay in analysis can compromise the integrity of the evidence. Forensic dentists are responsible for examining the definition of individuals suspected of bite mark perpetration, ensuring timely and accurate assessment. 
7. Polymerase chain reaction – In ultrasound, a technique is employed to enhance short, low-quality target DNA sequences for the purpose of detecting an individual’s sex. This method involves amplifying target DNA sequences through a series of temperature cycles using specific primers that bind to these sequences. Subsequently, “Gel electrophoresis” is utilised to visualise the amplified DNA fragments, enabling the determination of a person’s sex based on the presence or absence of specific DNA bands. 
8. Cryogenic grinding – this technique for sample collection involves preserving the entire tooth at extremely low temperatures using liquid nitrogen and then grinding it into a fine powder. Another less invasive method is to drill the root canals and scrape the pulp area. These methods are designed to maintain the integrity of the tooth structure and prevent any degradation or alteration of the sample. Cryogenic grinding is particularly effective in minimising damage to surrounding tissues and preserving the quality of the extracted material for subsequent analysis.
9. Demirjian Method – estimating the age of children can be challenging due to their rapid growth and development. One commonly used method is this method that assesses the development of mandibular left teeth by dividing them into ten stages. These stages range from zero, indicating tooth calcification, to nine, representing the completion of tooth calcification. By assigning scores to the stages observed, the total score is then used to determine the child’s chronological age. 

LEGAL STANDARDS FOR THE ADMISSIBILITY OF DENTAL EVIDENCE IN COURT OF LAW

In this growing world, science has become an unstoppable and indispensable aspect of human's daily lives, that has made huge impacts on society. Medical science or science in general has an influence that extends far and wide in the fast-paced society, and it not only affect society but even the law and criminal justice realms. Judicial pronouncements frequently underscore the enduring significance of scientific evidence in legal proceedings, highlighting its pivotal role in the quest for justice. Forensic evidence, in particular, occupies a central position in our criminal justice system, serving as a cornerstone in the pursuit of truth and fairness. “Evidence” defined under Section 3 of the Indian Evidence Act of 1872, encompasses both oral and documentary forms, reflecting the broad spectrum of information admissible in court. In criminal prosecutions, a diverse array of evidence is employed, with scientific and forensic evidence assuming paramount importance. Blood, hair, fingerprints, shoeprints, and other physical evidence hold significant weight in substantiating legal claims, rooted in scientific methodologies and principles. 

India has witnessed a remarkable surge in the utilisation of forensic evidence within its criminal justice system in recent years. This surge can be attributed to a growing recognition of the pivotal role of scientific proof in criminal investigations, coupled with the establishment of specialised forensic facilities nationwide. The Central Forensic Science Laboratory (CFSL) stands as India’s preeminent forensic institution, with regional units spread across the country. 

Forensic evidence plays a crucial role in criminal investigation in India, aiding in suspect identification, fact establishment, and linking perpetrators to crime scenes. The admissibility of forensic evidence in court hinges on several factors, including its relevance, reliability and authenticity, courts meticulously scrutinize the legitimacy, transparency, and accuracy of such evidence to arrive at sound conclusions. Expert testimony, deemed admissible under landmark cases such as “Frye V. United States” and “Daubert V. Merell Dow Pharmaceuticals”. In the case of “Fyre V United States” the court here observed that “The rule is that the opinions of experts or skilled witnesses are admissible in evidence in those cases in the subject of the inquiry is such that unskilled persons will able to derive the accurate decision on it involves subject aspects of science, art or trade that knowledge of it requires prior study or experience. When a question falls on the purview of general knowledge or experience and specialized knowledge or expertise in that particular science, art, or trade to which the question relates are admissible in evidence.”

Dental evidence has been recognised by the courts, as established in the case of “State V. Sapsford”. In this case, a rape victim’s body was found with “Bite marks”, the first suspect was released after his dental evidence did not match the marks, the second suspect, Sapsford, was arrested, and the court ordered the collection of his dental evidence and wax impressions, Sapsford refused, claiming it violated his constitutional rights. The court, however, rules that dental casts, wax impressions and photographs are legitimate tangible physical evidence and are not protected by the privilege against “self-incrimination”. The court determined that extracting dental evidence for identification purposes does not violate the right against unreasonable search and seizure. This was the first case in Ohio to consider dental evidence, and it set a precedent for future cases. 

In the case of the “Nirbhaya case”, the conviction of the accused relied significantly on forensic odontology. Bite marks analysis found on the victim was compared with the dental models of the suspects. The bite marks on the then-investigated photograph during the case were determined with reasonable medical certainty to be caused by the teeth of the culprit (Ram Singh). Similarly, the bite marks on other photographs showed specific features unique to Ram Singh’s dental profile. At least three bite marks were attributed to Ram Singh. Another bite mark on the photograph was matched to another culprit in the case (Akshay), based on the distinctive orientation of his left first “Incisor” and other unique dental characteristics. 

The forensic report linking Ram Singh and Akshay strengthened the prosecution’s case, bite mark evidence, though less reliable and specific than fingerprints or DNA due to potential changes in human teeth over time, provided crucial support in this case. Forensic odontology has established itself as an important field in medico-legal matters, and expert evidence from this discipline has been utilized effectively by courts to administer justice. The credible forensic odontology report, in this case, contributed to the capital sentences handed down to the accused. 

In cases of sexual harassment and assault, expert opinions in forensic odontology are particularly relevant and reliable. The bite mark evidence in the Nirbahaya case, matching the accused individual dental structures, demonstrated the significant role forensic odontology plays in the justice system.

CONCLUSION

Forensic odontology has proven to be the most important aspect of forensic science, providing crucial support in the identification of victims and the analysis of bite marks evidence in criminal cases. The integration of dental science into legal and criminal investigations has significantly enhanced the accuracy and reliability of evidence presented in court. In the case of “State V. Sapsford” and “the Nirbhaya Case”, highlight the pivotal role of dental evidence in giving justice to the victims who suffered showcasing the legal recognition and importance of forensic odontology. The application of forensic odontology extends beyond individual cases, offering invaluable assistance in mass disaster scenarios and in identifying victims where traditional methods fall short. The discipline's ability to identify unique characteristics and perform detailed analyses has cemented its place as a vital tool in the criminal justice system, despite its limitations compared to other forensic methods like DNA analysis, the specificity and reliability of dental evidence continue to support its relevance and utility. 

Forensic odontology advanced with technological innovations and improved methodologies, and its contribution to the field of forensic science and legal proceedings will undoubtedly grow. The commitment of forensic odontologists to maintain rigorous standards and provide accurate, scientific valid evidence further solidifies their role in administering justice and supporting the legal system in various capacities. Through continuous education, adherence to legal standards and the development of best practices, forensic odobtol9gy will remain a cornerstone of forensic investigations aiding in the pursuit of justice for victims and society as a whole.