|Year : 2021 | Volume
| Issue : 2 | Page : 101-107
Envisioning forensic odontology under a new light: A pedodontist's perspective
Supreet Shirolkar, Khooshbu Gayen, Subir Sarkar, Subrata Saha
Department of Pedodontics and Preventive Dentistry, Dr. R. Ahmed Dental College and Hospital, Kolkata, West Bengal, India
|Date of Submission||03-Sep-2020|
|Date of Decision||03-May-2021|
|Date of Acceptance||07-May-2021|
|Date of Web Publication||30-Jun-2021|
Dr. Supreet Shirolkar
Department of Pedodontics and Preventive Dentistry, Dr. R. Ahmed Dental College and Hospital, Kolkata - 700 014, West Bengal
Source of Support: None, Conflict of Interest: None
Forensic dentistry is an emerging field of science and it incorporates a wider scope for growth. It has developed itself as an important science in medical and legal matters and in the identification of the deceased person or an abuse victim. Forensic identification often requires an interdisciplinary approach. A pedodontist can help a forensic odontologist by applying their skills for recognition and reporting of child abuse and neglect, age assessment, bitemark analysis, and labeling of appliances that could provide vital clues for person identification. The American Academy of Pediatric Dentistry has prepared a guideline for record keeping that may provide pedodontist the information to accurately compile the records that will help the investigators. The aim of this article is to provide an overview of evolving trends in conventional methods and newer techniques and to discuss the role of pedodontist and how it can contribute to procedures needed for investigation in forensic odontology.
Keywords: Aadhaar card, bitemarks, DNA fingerprinting, forensic odontology
|How to cite this article:|
Shirolkar S, Gayen K, Sarkar S, Saha S. Envisioning forensic odontology under a new light: A pedodontist's perspective. SRM J Res Dent Sci 2021;12:101-7
|How to cite this URL:|
Shirolkar S, Gayen K, Sarkar S, Saha S. Envisioning forensic odontology under a new light: A pedodontist's perspective. SRM J Res Dent Sci [serial online] 2021 [cited 2022 May 27];12:101-7. Available from: https://www.srmjrds.in/text.asp?2021/12/2/101/319871
| Introduction|| |
Forensic odontology has been described in various ways as the application of dental science to the administration of the law and the furtherance of justice. Forensic odontology is one of those unique applications and has broad usefulness that cannot be overlooked for investigations.
The first treatise on forensic odontology entitled “L'ArtDentaire en Legale” as a subject in its own right was written by Dr. Oscar Amoedo in 1898 who is recognized as the father of forensic dentistry. Federation Dentaire Internationale stated forensic odontology as that branch of dentistry which in the “interest of justice deals with proper handling and examination of dental evidence and with the proper evaluation and presentation of dental findings in the interest of the dentist.”
This branch emphasizes the importance of dental evidence for the identification of victims and suspects in many criminal cases and in mass disasters. It plays a crucial role in the identification of natural disasters and those which are caused by humans. In cases of child abuse, the pediatric dentist's expertise in recognition of different signs and symptoms of child abuse and identifying the victims will help the investigating officers. Furthermore, a pedodontist can help a forensic odontologist by retaining the dental records of a pediatric patients and providing the same during an investigation or by labeling the fabricated appliances with appropriate identification methods. Cases that cannot be detected by facial identification or may be fingerprints can be found using newer forensic dentistry techniques.
The purpose of this review article is to provide an overview of changing trends in traditional methods along with insight of newer techniques, as well as to discuss the role of the pedodontist in forensic odontology procedures.
| Attribution of the Dental Structures in Forensic Odontology|| |
Tooth has been used as the foundation for the conclusive identification of living/deceased individuals utilizing distinctive attributes and traits of teeth and jaws. The tooth is considered to be the strongest and indestructible structure in the oral cavity which is resistant to post mortem decomposition. Similar to bitemarks, dental impression is considered to be an indispensable instrument which are more special than DNA. Among identical twins, the same genetic code is shared but their experiences vary. For the identification of badly burned, traumatized, decomposed, or skeletonized bodies and in major disasters, dental evidence is helpful.
Dental pulp is considered as richly vascularized and innervated connective tissue of mesodermal origin enclosed by dentin with communications to periodontal ligament. Evaluation of tissue alterations such as reduction in size of pulp chamber, dystrophic pulpal calcifications and pulp tooth ratio have been valuable in identification of human remains in forensic odontology.
| Comparative Identification of Antemortem and Postmortem Records|| |
Orchestration of postmortem dental remnants with antemortem dental records for confirmatory identification. Antemortem documents may be used, such as cariology profile, absence of teeth, radiographs, photographs, research casts, and clinical notes. As there are fewer restorative treatment and radiographic signs, there can be no or partial equivalent data available in children under 5 years of age. If the child is 5–6 years old, bitewing radiographs are always part of the dental records irrespective of any treatment. Common maturational change seen in the children like replacement of deciduous teeth with its permanent successor has led to another concern. However, this latter approach may be used for positive identification by determining the age at death. Computer-generated dental records are becoming more popular because they can be easily interconnected and transferred for routine professional consultations or forensic cases necessitating dental records for identification.
| Reconstructive Identification by Post Mortem Dental Profiling|| |
This is carried out when there is practically no clue on the decedent's identity. It covers the ethnic origin, sex, and age of the decedent, and by examining the genetic and environmental factors of the teeth through metric and nonmetric analysis, the person's ethnic origin can be identified.
| Sex Determination|| |
Sex/gender identification using skeletal remains is a major challenge for forensic scientists, particularly where only body parts are retrieved. Forensic odontologist may assist other expert to ascertain the sex of the remains using teeth. Sex determination analysis from teeth can be done via morphological analysis or molecular analysis. Methods of sex determination are given in [Figure 1].
Mesiodistal and buccolingual measurements of teeth are excellent indicators of sex, also being the easiest and most reliable method for analyzing sexual dimorphism. Significant differences have been found between maxillary incisors, premolars, and first and second molars. Bossert and Marks in their study reported that assessment of permanent mandibular and maxillary canine teeth for sex determination has some advantages in that they are the least extracted teeth, less affected by periodontal disease, last teeth to be extracted, and have a higher chance of surviving severe traumas; hence, the canines are considered to be an important tool for personal identification as it is known for exhibiting the greatest sexual dimorphism.
In sex determination, the dental index (mandibular canine index [MCI]) reported 86% of the success rate in the study conducted by Nair et al., in the South Indian population. The study carried out by Shankar et al. showed a statistically significant difference in right MCI in males and females. MCI differs from population to population of different geographical areas. The study done by Reddy et al. in the Western Uttar Pradesh population showed standard MCI to be 0.256, whereas the study by Rao et al. and Patel et al. showed a value of 0.274 in the South Indian population and 0.254 in the Gandhinagar population, respectively., The higher MCI value indicates male, and the lower is female. It is measured by calculating mesiodistal mandibular canine crown width and mandibular canine width.
Barr bodies are deeply stained chromatin material found in the nucleus of female somatic cells, which plays a key role in human gender identity. Barr bodies resemble alphabets such as V, W, S, or X. Barr bodies remain preserved until 1 year in dehydrated pulp. These are dormant X chromosomes that display sexual diagnostic features when heated for 1 h to 100°C. Y chromosomes consist of F-bodies, which can be used for sex determination. In a study by Reddy et al., the female cells displayed fibroblasts with peripheral Barr chromatin condensation at 100°C, 200°C, and 400°C, while the males lacked Barr chromatin but showed a fibrovascular connective tissue stroma. Studies have shown that pulpal tissues contain F-bodies. Fluorescent staining of Y chromosome in healthy pulps is the most efficient and reliable method of gender determination. The sex-determining region Y (SRY) gene extracted from pulp DNA can be used in forensic samples for the purpose of gender determination. These SRY genes are located in the short arm of the Y chromosomes at position 11.3 and are responsible for encoding a protein called the sex-determining region Y protein which is involved in male sexual development.
Amelogenin is a major matrix protein that is involved in the enamel production process and is crucial to normal dental development. Developing human enamel contains approximately 30% protein, of which 90% is amelogenin. DNA consists of AMEL X gene and AMEL Y gene. Thus, the female has identical AMEL genes, and the male has two separate AMEL genes. These genes help in the determination of sex in minute samples.
DNA extracted from the pulp is of two types, nuclear DNA and mitochondrial DNA. Various methods can be used to analyze the DNA, which include restriction fragment length polymorphism and polymerase chain reaction (PCR). DNA amplification by PCR gives 100% success in sex determination. [Figure 2] represents the flow process chart of PCR for sex determination.
|Figure 2: Flow process of polymerase chain reaction for sex determination|
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| Age estimation|| |
Forensic age assessment was described as a scientific method that estimates the individual's chronological age by evaluating skeletal and dental development and maturation. Methods of age determination are given in [Figure 3].,,,,,,,,,,,,
Pedodontist's knowledge regarding different events related to primary tooth germ formation and permanent first molar formation can help the investigator for assessing prenatal, neonatal, and early postnatal age. For the age estimation in neonates by dry weighing method, the cusp tips and incisal edges are vital., In deciduous teeth, due to stress and physiological changes at birth, a prominent incremental line of demarcation between prenatal and postnatal enamel is seen, which is called as the neonatal line. It has legal implications in feticide and infanticide.
It has long been established that dental age estimation techniques involving tooth maturation are the most accurate indicators of chronological age in subadults. Age estimation will be aided by the radiographic analysis of the developing dentition as well as the emergence of clinical tooth in various phases. Modified Demirjian technique is sex specific and is an excellent technique for age estimation in children.
The regression formula given below for age determination in Indian children was formulated by Acharya.
Male age = 27.4351− (0.0097 × S2) + (0.000089 × S3)
Female age = 23.7288− (0.0088 × S2) + (0.000085 × S3)
Age estimation in adults done in three different categories: (A) morphohistological methods, (B) radiological methods, and (C) biochemical methods.
Gustafson gave the first technique for age estimation based on the assessment of certain regressive changes in teeth. This method is a morphohistological method and is applicable on single-rooted teeth. The age changes are attrition of the enamel/dentin (A), secondary dentin deposition (S), alteration/recession of periodontal ligament (P), cementum apposition (C), root resorption (R), and transparency/translucency of dentin (T).
Sectioning technique by Johanson is a modification of Gustafson method. The method recommends that the dental occlusion be examined noting the number of teeth present, location, and potential habits.
Lamendin et al. included age assessment variables such as root transparency and periodontal recession in their study. Lamendin's regression formula for age assessment is as follows:
Age= (0.18 × P) + (0.42 × T) + 25.53
Where P and T are defined as P= (measured periodontal recession height × 100)/measured root height T= (measured root transparence height × 100)/measured root height Kim et al. used tooth wear as a criterion for an age estimation in living persons. They suggested a combined sum of tooth wear area (horizontal factor) and dentin exposure extent (vertical factor) could provide a better and reliable scoring system.
Kvaal et al. proposed a method by measuring pulp radiolucency on periapical radiographs based on indirect measurement of secondary dentin deposition. The size of the dental pulp cavity is reduced by secondary dentin deposition and measurement of this reduction can be used as an age indicator. This method is very useful when it comes to determining whether a person is under the age of 18 years or above.
Cameriere et al. put forward Italian formulae for estimating age on maxillary and mandibular canines using the pulp and tooth area ratio (PTR). A customized formula was presented by Babshet et al. for age estimation in Indian population using PTR. PTR was measured from the mandibular canine: the formula for age was 64.413-195.265 × PTR.
Yang et al. have developed a new technique using cone-beam computed tomography scans to capture three-dimensional (3D) images of teeth in living individuals. The pulp/tooth area ratio could be calculated using these 3D images, with promising results for estimating age.
The racemization of amino acids is used as a biochemical age indicator. Aspartic acid has a speedy racemization rate (high in root dentine). L-aspartic acid undergoes racemization to be stored in increasing amounts as D-aspartic acid during aging. Hence, the ratio of L- and D-aspartic acid at different ages is constantly changing. This D/L ratio may be used to estimate age. The age estimate for this method is within ± 3 years of actual age.
Spalding et al. suggested that the radiocarbon content present in tooth enamel is a remarkably precise age predictor.
The DNA of dental pulp may also be used to estimate an individual's age. During the aging process, chromosome length reduction can be seen in which telomere shortening occurs. Due to nonreplication of DNA polymerases at the end of linear molecules, shortening of cell division occurs at each cell division. The estimation of telomere shortening of extracted DNA from pulp is thus a valuable method for determining age at death.
| Dental DNA Fingerprinting|| |
DNA fingerprinting is a multistep laboratory process involving pulp removal from the tooth followed by DNA isolation and DNA analysis. Teeth are considered to be an excellent source of DNA since it can resist to extreme condition. Pulpal tissue is the best source of dental DNA as it is rich in various cellular elements such as fibroblasts odontoblast, endothelial cells, undifferentiated mesenchymal cells, and nucleated components of blood. In primary teeth, DNA can be obtained mainly from two sources, dental pulp stem cells and stem cells from human exfoliated deciduous teeth which represent a population of postnatal stem cells capable of extensive proliferation and multipotential differentiation.
| Collection of Patterned Marks|| |
Lip prints (cheiloscopy)
The pattern of wrinkles on the lips has unique features, such as fingerprints, and does not change during life of a person, so it serves as useful evidence in forensic odontology. Lips are natural lines and cracks in the shape of folds and grooves found in the human lip transformation region between the inner labial mucosa and the outer skin, the analysis of which is known as cheiloscopy. Lip print recording is helpful during a crime scene examination; lip prints will connect the victim to a particular position whether they are located on cloths, plates, cups, or even cigarette butts. A lip print demonstrates a surface with visible elements of furrow lines. This feature helps identify an individual's gender [Figure 4]a.
|Figure 4: Patterned marks. (a) Lip prints, (b) Palatal rugae pattern, (c) Reference points for determining shape of the tongue|
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Palatal Rugae in identification
Palatal rugoscopy may be the perfect criterion for diagnosis, because the rugae do not experience any alteration except in length. Palatal rugae have been shown to be unique to every individual and consistent throughout life. Any sort of diseases/disorder, chemical attack, or trauma do not seem to change the palatal rugae pattern. Palatal rugae identification includes tracing the rugae patterns from ante- and postmortem dentures, making digitalized images of the palate and plotting the characteristics points which include medial and lateral extremities of rugae. The plotted points will be calculated by the software system and the processed knowledge corresponded sequentially to the set location. The most popular rugae pattern was sinuous, followed by curve, line, spot, and polymorphic varieties [Figure 4]b.
The dorsal surface of the tongue is unique to every individual. The characteristic features of the tongue show a remarkable difference even between identical twins. Tongue exhibit sexual dimorphism with sharp tip at the lingual apex present in females whereas septate tips in males. When used in conjunction with methods such as cheiloscopy and rugoscopy, lingual impressions (printing of the dorsal surface along with the lateral borders) have been proved to be useful in forensic dentistry identification. Three reference points were considered for the shape of the tongue [Figure 4]c.
A bitemark on human skin is a patterned injury, and forensic odontologists often take responsibility for examining and analyzing those injuries. Resulting examination of indentations to the dentition of the suspected biter(s) is a different and distinct action. Analysis should be done of all suspected bitemarks. It can be done by various newer techniques such as 3D scan overlay technique; Adobe Photoshop software is one of the most widely used in bitemark comparison overlay. Another software application, DentalPrint, was created by the University of Granada's Department of Forensic Medicine and Forensic Odontology to generate comparison overlays from 3D images of the suspect's dental casts. Only those which reach an evidentiary value threshold should be compared with the suspected biters. Biting is considered to be a type of a primitive assault, which is always associated with sexual abuse, violent fights, and even child abuse. The dentist should learn how to conduct a clinical examination of suspected cases of child abuse that present clinically as sexual abuse. In suspected child abuse cases, hard tissue categorization (traumatic injuries to teeth based on the Ellis classification) and detailed tooth mark examination are performed. Tooth marks on the skin can occur as a result of hemorrhage, contusion, laceration, incision, or avulsion. In a recent study done on dentist's role in detecting child abuse in India, it was found that dentists were hesitant and unaware of the appropriate authority to report the case and increased awareness in this aspect should be emphasized. Hence, pedodontist should carefully observe and document bitemarks and be encouraged to be knowledgeable about such findings and their relevance.
| Forensic Aspect in Pediatric Dentistry and Role of Pedodontist in Forensic Odontology|| |
Pediatric dentistry is that dental specialty concerned with the treatment of dental diseases in children. A pedodontist can help in recording antemortem data as he deals with each and every aspect of child's development, which includes physiological, psychological, and dental development like eruption and shedding sequences, endodontic therapy, and associated syndromes which may be useful in identification. Dental records of pediatric patient should be maintained until the patient reaches the age of maturity. A pedodontist should preferably follow guidelines provided by the American Academy of Pediatric Dentistry for maintaining dental records. A pedodontist can incorporate various labeling in the appliance which contains data pertaining to one's identity.
Identification clues can be provided by these appliances. These can be useful in disaster victim identification where dental records are considered as one of the primary methods of identification. Aadhaar card number is a unique identification number which is compulsory for every citizen of India; Baal Aadhaar card is given to children below 5 years of age in which one's personal identification is feed in government database which can be accessed by forensic personnel. The Aadhaar card number and the QR code can be labeled on occlusal surface of the appliance [Figure 5].
Pediatric dentistry also plays a major role in understanding child abuse that can clinically manifest as physical violence, neglect, sexual abuse, and emotional abuse; thus, a pedodontist can play an important role in the identification of bitemarks. A pedodontist should have knowledge in forensic dentistry to properly recognize the signs and symptoms of child abuse and to help the legal officers to investigate. Pediatric dentists may also provide valuable information for physicians dealing with oral and dental child abuse and neglect.
Limitations and shortfall according to the pedodontist's point of view are as follows:
- As a child is in constantly growing phase, there are variations in orodental morphology, i.e. transformation from deciduous to permanent dentition; moreover, antemortem records are scant or either incomplete which can mislead the investigators
- Many cases of child abuse go unreported due to lack of verbal communication between child and guardian; this is usually due to child's fear to discuss the incident
- Delay in reporting of bitemarks found on the victims may hinder the investigation as they change in a relatively short duration, which necessitates the recording of the marks in earliest possible way
- Lack of awareness among the parents regarding signs and symptoms of child abuse from external environment may be at school or in the peer group
- Nonmaintenance of sufficient dental records of children is the main shortfall seen in current times.
| Future perspective|| |
- 3D imaging and facial and dental scanning: The use of 3D datasets for comparison of bitemark analysis and facial reconstructions and for identification of individuals in disaster. CAPMI and WinID are the recently developed imaging software which have better control to minimize the human error.
- Dental nano biochip containing valuable information for identification can be inserted on the tooth like studs.
- Dental DNA bank: Genomic DNA is unique to every individual which can be preserved from the pulp tissues of tooth which undergoes therapeutic extractions.
- Epiluminescence microscopy is a recent advancement in documentation of bitemark records. This technique, through the translucency of the stratum corneum, helps with visual representation and pictorial documentation.
| Conclusion|| |
Dental records such tooth structure, shape, photographs, palatal rugae, lip prints, tongue prints, and other variations in facial profile which are unique to the individuals play a major role in establishing the identity of the unknown person and also the living victims of the child abuse. With current advent modern techniques, identification of person using dental records has ease the work of the forensic investigators. Computer-aided forensic analysis and DNA fingerprinting are upcoming techniques, which will be beneficial in future forensics.
Pedodontists have the responsibility to understand the forensic implication associated with their practice. As pediatric dentistry is a specialty which constantly deals with a child, it plays an important role in child abuse and neglect.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]