|Year : 2019 | Volume
| Issue : 2 | Page : 71-75
Radiographic determination: An upcoming aid in forensic radiology
Department of Oral Medicine and Radiology, RR Dental College and Hospital, Udaipur, Rajasthan, India
|Date of Submission||27-Aug-2019|
|Date of Acceptance||08-Oct-2019|
|Date of Web Publication||23-Dec-2019|
Dr. Tarun Vyas
Department of Oral Medicine and Radiology, RR Dental College and Hospital, Umarda, Udaipur - 313 001, Rajasthan
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The identification technique utilizing conventional radiography is of much importance in forensic odontology for age and gender determination. Various radiographic images that can be used in forensic odontology are intraoral periapical radiographs, lateral oblique radiographs, cephalometric radiographs, panoramic radiographs, and advanced imaging techniques. Recently, digital radiographs have also gained importance in comparison between antemortem images recorded in dental offices and centers with postmortem radiographic images for individual identification. This along with the facility of internet has made dentomaxillofacial radiographs, a useful tool in forensic science. This article aims for the evolution in forensic radiology and to appraise their contribution in the field of forensic odontology.
Keywords: Age estimation, cone beam computed tomography, digital method, forensic odontology, personal identification
|How to cite this article:|
Vyas T. Radiographic determination: An upcoming aid in forensic radiology. J Int Clin Dent Res Organ 2019;11:71-5
| Introduction|| |
The word forensic is derived from the Latin forensic which means “before the forum” from ancient Rome; the forum was where trials and debates took place and consequently served as a court of law. On the other hand, odontology refers to the study of teeth or dentistry. Keiser–Nielsen has defined forensic odontology as “a branch of dentistry which deals with the proper handling and examination of dental evidence and with the proper evaluation and presentation of dental findings in the interest of the dentist.” The identification of human remains is one of the most essential aspects of forensic science. As there is no humanitarian character to forensic medicine, Dr. Oscar Amoedo is considered as “the father of Forensic Odontology.”
The application of radiology in forensic sciences was introduced in 1896, just 1 year after the discovery of the X-ray by Roentgen, to demonstrate the presence of lead bullets inside the head of a victim. Forensic radiology usually comprises the performance, interpretation, and reportage of those radiological examinations and procedures that have to do with the courts and/or the law. Imaging techniques are a powerful tool in forensic science. The radiologist should be aware of the importance of storing radiographs over prolonged periods of time and of efficient record keeping methods because various legal problems may require the radiograph for additional interpretation or for their presentation in court.
Dental radiographs constitute crucial information that plays an important role in the registration, detection, collection, and preservation of forensic evidence. These records are of major significance during comparative dental identification, postmortem profiling, and certain age estimations.
Today, radiographs are a common diagnostic tool, widely used in dental practices, hospitals, and health services throughout the world. Storage facilities exist in most health institutions which keep radiographs over long periods of time.
Radiographically assisted dental identification may be comparative or reconstructive in type. The former “compares” antemortem radiographs with postmortem radiographs. Reconstructive identification may use radiographs as an aid in the generation of a biological profile of a person for whom the putative identity remains unknown.
Radiographic records provide objective evidence of the anatomical conditions and the dental treatment provided up to the point in time. Most cases of comparative identification use radiographic evidence of dental intervention (restorations, root fillings, crowns, extractions, etc.) as common points of identification. Less commonly, anatomical features are used as concordant points. Dental interventions, especially restorative ones, in many cases provide unique identifiers that are common in antemortem and postmortem examinations.
Radiography being a nondestructive method also plays a vital role in forensic dentistry to uncover the hidden facts, which cannot be seen by means of physical examination. The conventional radiographic methods allow the observation of anatomical characteristics such as coronal shape and size, pulp anatomy, positioning and shape of the alveolar bone crest, besides unique and individual characteristics resulting from dental treatments.
| Personal Identification|| |
Identity, by definition, is the ensemble of characteristics that allow the individualization of a person or an object, distinguishing other subject from any other person or object. Identification is the act by which the identity of an individual is established and is of unquestionable value since social relations and/or civil, administrative, commercial, and legal demands claim this form of recognition. The premortem and postmortem properties of a person in the teeth are unique. They can be analyzed for the purpose of forensic identification.
Tooth has been used as quite reliable evidence in personal identification of living or dead persons using the specific features of the jaws and the teeth. Several researchers have advocated the uniqueness of tooth. Many scientists believe that tooth impression is more usable evidence than the bite marks, which are believed to be more specific than DNA. The genetic makeup may be same in both the twins but the dental impression may be different.
Dental and medical problems are ultimately concerned with the determination of each patient as a unique individual. Similarly, medicolegal identification is based on a set of characteristics which define the physical “uniqueness” of each individual. It follows that a close relationship exists between human identification, individuality, and the biological sciences.
From the calcification of deciduous ones to the loss of permanent ones, the teeth, with their sequence of formation and eruption, have been used as indicators of age, mostly in the period from early childhood to adulthood. Radiology plays an indispensable role in human age determination. Radiological images are utilized in the process of age estimation, which is one of the essential tools of identification in forensic science. Saunders, a dentist, was the first to publish information regarding dental implications in age assessment by presenting a pamphlet entitled “Teeth A Test of Age” to the English parliament in 1837. While quoting the results from his study on 1000 children, he pointed out the value of dentition in age estimation.
In children and young adults, age estimation is done by clinical methods such as eruption sequence, radiographic methods such as Schour and Massler method, Moorer, Fanning and Hunt method, Demirijian, Goldstein and Taners method, and Nolla's technique.
According to recent research, tooth cementum angulation may be used more reliably than other methods for age estimation.
Analysis of these various radiographic features in the dentition of an individual corresponding to the phase of human development aids in age determination. These can be grouped into three phases:
- Prenatal, neonatal, and postnatal
- Children and adolescents and
For age determination, two methods are commonly used: the “ Atlas More Details method” in which radiographic dental development (mineralization) is compared with published standards and the “Scoring method” in which dental development is divided into various stages that are then assigned the scores that are evaluated through statistical analysis. Acharya has been credited to utilize Demirjian's criteria to assess the third molar development by analyzing the orthopantomographs (OPGs) of 221 Indian individuals belonging to the age group of 15–21 years. He came to the conclusion that a significant one-fourth population of India has been wrongly analyzed for age estimation and have been placed in wrong age group.
Sex determination through dental radiographs
Sex determination is an important step for identification of human remains and for medicolegal investigations in forensic odontology. There are various methods for sex determination in forensic dentistry, but by assessing the symmetry, morphology, border outline and presence of septa and cells of the frontal sinus in dental radiographs has gained much attention. The frontal sinuses are two, in the posterior part of the supercilliary arcs, and lies between the external and internal faces of the frontal bone. They are seldom symmetrical; generally, there is a septum between both, which usually deviates from the midline. They point upward beyond the middle part of the supercilious and backward to the medial part of the orbital roof. Frontal sinus radiographs may be used because it is commonly exposed in sinus series investigations. Camargo et al. studied morphology of frontal sinus in radiographs of Brazilian population and found accuracy rate of 79.7% using logistic regression model in sex determination.
Various studies have been conducted in the past to evaluate the forensic importance of frontal sinus radiograph., Studies report that, statistically, the frontal sinuses are larger in men than in women, and in women, the upper borders of the frontal sinuses are deeper. Furthermore, other factors may affect the regular anatomy of the frontal sinuses in adult individuals, as follows: fractures, traumas, surgeries, diseases, mucoceles, and some enlargement in elder individuals, all of them of rare incidence.
Digital radiography used for a decade or more by radiologists has become the solution of choice in mass casualty situations where the number of victims overwhelms the ability of forensic medical examiners to quickly and accurately identify descendents.
“Digital radiography dramatically increases the quality and timeless associated with the use of dental X-rays in forensic dental victim identifications, particularly when combined with computer based dental chart matching software.”
The process of identification based on conventional radiography became more difficult because of the dissemination of prophylactic dental treatments and the consequential, significant reduction in the incidence of cavities, particularly in developed countries.
Innumerable variations of digital radiology techniques can be found in the literature, but, essentially, the method comprises the following steps: (1) radiographic image digitization with the aid of a scanner, video camera, or yet with images' acquisition directly from a X-ray system coupled with a computer with monitor, printer, and CD-ROM recorder; (2) image processing through an appropriate software, allowing comparisons based either on image superimposition, interposition, or subtraction.
These modern techniques allow an accurate analysis of the spatial relations of teeth roots and supporting structures on ante- and post-mortem images. There are softwares with resources for images rotation, translation, and scaling, facilitating the correct alignment between ante- and post-mortem radiographs without the necessity of new exposures. It is important to observe that differences in the geometry between radiographs represent the main factor of error in this type of technique, and the abovementioned correction is essential to reduce the noise resulting from the process of image subtraction. Forensic dentistry plays a major role in the identification of those individuals who cannot be identified visually or by other means.
Conventional, two-dimensional, or three-dimensional (3D) computed tomography (CT) is a useful imaging method in the process of human identification and presents innumerable advantages in this field as compared with the traditional radiographic projection. First, its noninvasive, no magnification error, and present 3D images of the third molar whether it is angulated on adjacent structures. Both CT and magnetic resonance imaging (MRI) are dependent on good scanning protocols that provide the desired spatial resolution to distinguish what we are looking for within a clinically acceptable acquisition of time. Multidetector CT (MDCT) is often used in forensic medicine since it has become more common to perform a postmortem CT before autopsy. Virtopsy or autopsy is a word which consists of “virtual” and “autopsy.” The previous term is derived from the Latin word virtus, which means “useful, efficient, and good.” Virtopsy basically consists of (a) body volume documentation and analysis using CT, MRI, and microradiology and (b) 3D body surface documentation using forensic photogrammetry and 3D optical scanning. The aim of the virtopsy project is to validate this new approach by systematically comparing the radiologic and surface scanning findings with those obtained at traditional autopsy Jagannathan et al. conducted a study and assessed the suitability of pulp/tooth volume ratio of mandibular canines for age prediction in an Indian population. Volumetric reconstruction of scanned images of mandibular canines from 140 individuals (aged ten -70 years) using CT was used to measure pulp and tooth volumes. And finally concluded that the pulp/tooth volume ratio is a useful indicator of age.
At the present time, 3D digital tooth images can be acquired from living individuals using CBCT., Yang et al. reported that using their three-dimensional images, the ratio of pulp/tooth volume could be calculated for living individuals. They selected 28 sets of CBCT tooth images(15 incisors, 12 canines, and 1 premolar) from 19 different individuals ranging in age from 23 to 70 years. The selection was restricted to upper and lower single-rooted teeth that revealed neither deep carious lesions nor restorations and showed normal dental anatomy. Thus, Yang et al. describe a first approach to age estimation. CBCT was used to calculate the pulp/tooth volume ratio in our study, for two reasons:
- The analysis of the volumes of the pulp chamber and tooth is more reliable than calculation of area ratios, possibly because secondary dentine formation may not be uniform along all pulp surfaces, and hence, measurements of projected areas could give an incorrect impression of the extent of this process
- CBCT is an accurate technique for studying the anatomy of the pulp chamber and root canal system which provides 3D volumetric information of the teeth of living individuals by a single scan and can be operated nondestructively. The newest CBCT operating modes and optimization of the ratio measurement software, together with increased numbers of samples, could bring the technique to maturity in forensic odontology research. We also believe that investigations employing larger sample sizes may also demonstrate that CBCT data can be helpful to study other aspects of dental morphology in greater depth, especially dental growth. CBCT data could be helpful in defining new parameters for the rating of dental development, for a quantitative description of the fractions of crown and root formed during tooth growth. Rangari in the present study was to develop a noninvasive, conservative, reliable, accurate, and simple method of dental age estimation by means of the analysis of the volume decrease phenomenon which affects the pulp cavity of the teeth using 3D radiographic images of the CBCT [Figure 1], [Figure 2], [Figure 3], [Figure 4]. The sample of single rooted teeth was selected from 20 CBCT radiographs in North Indian individuals of any gender and age between 15 and 60 years. The images consisting of the maxillary central incisor and canine of either side were selected in DICOM file format (OnDemand 3D software version: 1-0-10) by Cybermed company developed in Korea. The ratio of “pulp/tooth volume” has been obtained and then correlated with the age of the individual. The results have been statistically analyzed. There was a moderate correlation between chronological age and pulp/tooth volume ratio. The presented method is a promising tool in the procedure for age estimation, permitted by the high technological level achieved by the currently available machines for the CBCT.
|Figure 1: CBCT images of maxillary canine obtained for the study participants showing how to adjust the long axis within both the sagittal coronal and axial cuts. Rangari P et al. (used with permission)|
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|Figure 2: threshold values by selecting ROI. Rangari P et al. (used with permission)|
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|Figure 3: volume measurement using selection and segmentation of tooth by Pick pointer. Rangari P et al. (used with permission)|
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|Figure 4: volume measurement using selection and segmentation of pulp by Pick pointer. Rangari P et al. (used with permission)|
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It is foreseen by some people that CT will replace other modalities in forensic radiology and potentially some autopsies, mainly those on trauma patients. Much research is still needed in this area, and groups from around the world are working toward proving the validity of CT in forensic work.
Similarly, MRI has been used in forensic cases but has a limited role to play. The strong magnetic currents required limits the potential for use and most cases would need a MDCT prior to MRI scan. Obviously, the associated costs involved constrain the use of MRI, but this is a further avenue for research.
| Conclusion|| |
Thus, we can see that radiographic aids are proven as an excellent tool and have become vital component for medical and dental practice. They play important role in forensic radiography or odontology. Dental and craniofacial radiograph are an important assessment tool in race, gender and stature due diversity in human physical constitutional makeup. With recent advancement of technique such as CT, Micro CT, MRI, and OPG, CBCT also aids in forensic odontology. Even surgical means autopsy which are now used for radiology purpose further research and studies in the field of forensic radiology should be encouraged.
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]