Forensic aspects of maxillofacial radiology

The Role of an Endodontist in Victim Identification: A Narrative Review on Forensic Endodontics

This narrative review highlights the role of endodontists and the significance of various dental tools in forensic dentistry. An online search was conducted in peer-reviewed journals, including MEDLINE (Ovid), PubMed, Web of Science, Scopus, and Google Scholar databases, to retrieve studies regarding "the role of an endodontist in victim identification using different tools". The searches used controlled vocabulary and free-text terms. Articles written in English and published from 1923 to 2023 were selected. An essential stage in forensic dentistry is dental identification of the dead person and is regarded as an initial step for both judicial and humanitarian purposes if fingerprint records are missing or the remains have undergone significant changes. Endodontists should be aware of all available dental tools that aid in identification. The four fundamental tools for identification are dental radiographs, hard and soft dental structures, and dental materials. Dental radiographs provide a substantial nondestructive record for estimating age and sex. Moreover, maxillofacial hard and soft structures provide important tools for individual identification as they are considered the strongest structures in the human body and can withstand severe chemical and temperature changes. In addition, endodontic and restorative materials can be identified under different conditions and serve as excellent forensic identification measures.

The Accuracy of Sex Identification Using CBCT Morphometric Measurements of the Mandible, with Different Machine-Learning Algorithms-A Retrospective Study

In forensics, predicting the sex is a crucial step in identification. Many studies have aimed to find an accurate and fast technique to estimate the sex. This study was conducted to determine the accuracy of volumetric and linear measurements of three-dimensional (3D) images of the mandible obtained from cone beam computed tomography (CBCT) radiographs, using different machine-learning (ML) models for sex identification. The CBCTs of 104 males and 104 females were included in this study. The radiographs were converted to 3D images, and the volume, surface area, and ten linear measurements of the mandible were obtained. The data were evaluated using statistical analysis and five different ML algorithms. All results were considered statistically significant at p < 0.05, and the precision, recall, f1-score, training accuracy, and testing accuracy were used to evaluate the performance of the ML models. All the studied parameters showed statistically significant differences between sexes p < 0.05. The right coronoid-to-gonion linear distance had the highest discriminative power of all the parameters. Meanwhile, Gaussian Naive Bayes (GNB) showed the best performance among all the ML models. The results of this study revealed promising outcomes; the sex can be easily determined, with high accuracy (90%).

Cone-Beam Computed Tomography: A New Tool on the Horizon for Forensic Dentistry

Teeth and bones of calvarium are important structures from a forensic point of view, as they are extremely resilient to destruction or decomposition, even under temperature variations. Radiology is inevitably an important tool in forensic investigations. Maxillofacial radiology provides a considerable amount of information for the identification of remains and evidence in case of legal matters. The advent of cone-beam computed tomography (CBCT) in the arena of maxillofacial 3D imaging has contributed immensely to forensic science such as the age estimation through teeth, analysis of bite marks, determination of race and sex, etc. The advantages of accuracy in imaging the anatomy, digitized technology favoring easier comparison of records and storage of records for a longer period, cost reduction, dose reduction, and easier portability have made it an unavoidable adjunct in forensic investigations. The aim of this paper is to review and highlight the importance of CBCT in successful forensic identification and analysis. This review is written to address the various aspects of CBCT as a recently developed technology that may be very useful in some forensic contexts, based on searches for current studies in the literature using PubMed, Scopus, Web of Science, and Google Scholar databases, to identify studies published since inception to December 2021, with no language restriction. In conclusion, CBCT is an accessible 3D imaging technology with many applications, one of them being in forensic sciences.

Specific oral and maxillofacial identifiers in panoramic radiographs used for human identification

Radiographically assisted dental identification is an important means for individual identification. Specific identifiers help to quickly filter some of the possible corresponding AM and PM images at the beginning. The study seeks specific oral and maxillofacial identifiers in panoramic radiographs. A total of 920 panoramic radiographs from 460 live patients were used. The most recent radiograph served as the surrogate post-mortem (PM) record of an unidentified person, and the earliest radiograph served as the ante-mortem (AM) record of the same person. We evaluated the following four groups of identifiers of the images: (1) dental morphology, tooth number, and position; (2) dental treatment and pathology; (3) morphological identifiers of the jaw; and (4) pathological identifiers of the jaw. The ratio of each identifier being identified simultaneously in the AM and PM databases was determined. Specific identifiers were defined as those that appeared at low frequency (ratio: 0%-0.250%). A total of 18 specific oral and maxillofacial identifiers were determined. The specific identifiers were a retained deciduous tooth (0.011%), S-shaped deflection of a tooth root (0.012%), distal deflection of tooth root (0.017%), inverted impaction (0.018%), malposition (0.038%), supernumerary teeth (0.061%), mesial deflection of tooth root (0.092%), microdontia (0.136%), buccal/lingual impaction (0.188%), cementoma (0.002%), hypercementosis (0.002%), continuous crown (0.004%), pulp calcification (0.023%), attrition (0.030%), residual root (0.106%), root resorption (0.137%), implant (0.156%), and osteomyelitis (0.002%). Identifiers of the teeth and jaw can be used for human identification, and dental identifiers are more specific than identifiers of jaw.

Automatic human identification based on dental X-ray radiographs using computer vision

A person may be identified by comparison between ante- and post-mortem dental panoramic radiographs (DPR). However, it is difficult to find reference material if the person is unknown. This is often the case when victims of crime or mass disaster are found. Computer vision can be a helpful solution to automate the finding of reference material in a large database of images. The purpose of the present study was to improve the automated identification of unknown individuals by comparison of ante- and post-mortem DPR using computer vision. The study includes 61,545 DPRs from 33,206 patients, acquired between October 2006 and June 2018. The matching process is based on the Speeded Up Robust Features (SURF) algorithm to find unique corresponding points between two DPRs (unknown person and database entry). The number of matching points found is an indicator for identification. All 43 individuals (100%) were successfully identified by comparison with the content of the feature database. The experimental setup was designed to identify unknown persons based on their DPR using an automatic algorithm system. The proposed tool is able to filter large databases with many entries of potentially matching partners. This identification method is suitable even if dental characteristics were removed or added in the past.

Age estimation by pulp/tooth area ratio in anterior teeth using cone-beam computed tomography: comparison of four teeth

Objectives

Age estimation is one of the most important factors in forensic medicine. Measuring secondary dentin deposition using cone-beam computed tomography images is an easy and noninvasive method. The aim of this study was to evaluate cone-beam computed tomography images as a reliable method to estimate chronological age by pulp/teeth ratio in anterior teeth in Iranian population.

Methodology

A total of 649 CBCT images from 377 Iranian patients aged between 20 and 69 years were evaluated. Pulp/teeth ratio (PTR) in maxillary and mandibular canine and central incisor teeth was measured in the axial and sagittal sections using OnDemand 3D Dental software. The Pearson correlation coefficient was determined to evaluate the correlation between the variables. Linear regression analysis, as well as age estimation formula, was used for each tooth separately.

Results

The regression analyses indicated that maxillary central incisors were more reliable for age estimation (R²=0.586 and standard error of estimate=7.045) compared with the other anterior teeth studied. Maxillary canine teeth had the lowest predictive power (R²=0.392 and standard error of estimate=8.387). Also, comparison of the axial and sagittal sections showed that the axial sections had a higher predictive power. (R²=0.48 for axial plans and R²=0.328 for sagittal plans)

Conclusion

The use of cone-beam computed tomography in age estimation by pulp/teeth ratio of anterior teeth is useful and a reliable method for age estimation in Iranian population.

Forensic Identification of Decomposed Human Body through Comparison between Ante-Mortem and Post-Mortem CT Images of Frontal Sinuses: Case Report

Objective

The aim of this paper is to report on a case of positive human identification of a decomposed body after the comparison of ante-mortem (AM) and port-mortem (PM) computed tomography images of frontal sinus.

Case report

An unknown, highly decomposed human body, aged between 30 and 40 years, was found in a forest region in Brazil. The dental autopsy revealed several teeth missing AM and the presence of removable partial prostheses. The search for AM data resulted in a sequence of 20 axial images of the paranasal sinuses obtained by Multislice Computed Tomography (MSCT). PM reproduction of the MSCT images was performed in order to enable a comparative identification. After a direct confrontation between AM/PM MSCT, the data were collected for morphological findings, specifically for the lateral expansion of the left lobe, the anteroposterior dimension, and the position of median and accessory septa of the sinuses.

Conclusion

The importance of storing and interpreting radiographic medical data properly is highlighted in this text, thus pointing out the importance of application of forensic radiology in the field of law.

Sex Estimation from Human Cranium: Forensic and Anthropological Interest of Maxillary Sinus Volumes

Sex estimation is a key objective of forensic science. We aimed to establish whether maxillary sinus volumes (MSV) could assist in estimating an individual's sex. One hundred and three CT scans were included. MSV were determined using three-dimensional reconstructions. Two observers performed three-dimensional MSV reconstructions using the same methods. Intra- and interobserver reproducibility were statistically compared using the intraclass correlation coefficient (ICC) (α = 5%). Both intra- and interobserver reproducibility were perfect regarding MSV; both ICCs were 100%. There were no significant differences between right and left MSV (p = 0.083). No correlation was found between age and MSV (p > 0.05). We demonstrated the existence of sexual dimorphism in MSV (p < 0.001) and showed that MSV measurements gave a 68% rate of correct allocations to sex group. MSV measurements could be useful to support sex estimation in forensic medicine.

Association between frontal sinus morphology and craniofacial parameters: A forensic view

The aim of this study was to evaluate the morphologic structure of the frontal sinuses with postero-anterior cephalometric radiographs in Turkish adolescents and to compare the findings between genders. The study sample consisted of 148 subjects divided into two groups (74 male subjects; mean age: 14.55 ± 1.42 years-74 female subjects; mean age: 14.95 ± 1.80 years). The right and left maximum height and width of the frontal sinus, maxillary width, nasal width, cranial width, antegonial width parameters were measured in 148 postero-anterior cephalometric radiographs. The data were analyzed using independent t and Mann Whitney U test. Spearman correlation analyses were used to evaluate the relationships of the frontal sinus measurements and transversal cephalometric parameters. The mean values of the right and left frontal sinus width, maxillary width, antegonial width, and cranial width were larger in males than females (P < 0.05). The right frontal sinus height were positively correlated with antegonial width (r = 0.243; P < 0.05) and the right frontal sinus width were positively correlated with antegonial width (r = 0.327; P < 0.01) in males. The right frontal sinus width were positively correlated with nasal width (r = 0.244; P < 0.05) and the left frontal sinus width were positively correlated with nasal width (r = 0.231; P < 0.05) in females. Frontal sinuses were unique to each individual due to their morphological structures, and in forensic science, taking advantage of these features was very important for personal identification.

Guidelines for reproducing geometrical aspects of intra-oral radiographs images on cone-beam computed tomography

Human identification requires comparison of individual traits of a person, depending on the availability and reproduction of antemortem (AM) records. If there is no presumed identity or AM exams are not available for comparison, the production of postmortem (PM) records is impaired. The purpose of this research is to describe and test standards to enable the comparison of antemortem periapical radiographs to images extracted from the manipulation of postmortem CBCT exams in multiple identification simulations in a randomized blind study. In a simulation, 20 CBCT images from dry skulls were used as PM records and 3 periapical radiographs (total of 60) that were randomized and blinded from the first examiner. In each case, an intentional incidence error of 10° was added in four different directions. Three points were selected in the AM radiograph, and the angle, linear measurements and proportion between these distances were collected. The AM data were used to mathematically find similar image geometry on a CBCT maximum intensity projection. Possible identification by superimposition was achieved in all cases, and statistical analysis proved the success in the reproduction of angular and length proportion using CBCT incidence manipulation. Significant reproducibility was also observed on intra- and inter-observer tests. In conclusion, the images extracted from CBCT could be compared to any periapical radiographs by superimposition, providing acceptable evidence to establish human identification. The application of this protocol is suitable for forensic practices with the high level of reproducibility and could be used as PM record when no AM records are available at the time of the exam.

Human identification study by means of frontal sinus imaginological aspects

The objective of this study was to evaluate the applicability of human identification parameters, established by Tatlisumak et al. (2007), by means of cone-beam computed tomography and extraoral radiographs of the frontal sinus region. From a total of 58 dry skulls, 26 were selected. Posteroanterior, profile cephalometric radiographs and cone-beam computed tomography images were acquired, adopting a specific method for reproducibility purposes. The images were evaluated by two examiners, previously calibrated, in a darkened environment and at two distinct sessions, with a minimum of 15 days between them. The characteristics of the frontal sinus were analyzed using the Cohen's kappa test, for categorical variables, and Lin's concordance correlation coefficient (CCC) for continuous variables. Acceptable values of inter method variability for the categorical variables were found, while same cannot be told for continuous variables. The parameters evaluated for the frontal sinus on extraoral radiographs and cone-beam computed tomographs were mostly concordant, with the exception of three. Categorical and discrete variables showed an intra- and interexaminer concordance ranging from good to perfect, and the quantitative continuous variables showed concordance ranging from moderate to excellent. The parameters examined are applicable and reproducible using multiplanar reconstructions of cone-beam computed tomography and extraoral radiographs of the frontal sinus.

Age estimation by pulp-to-tooth area ratio using cone-beam computed tomography: A preliminary analysis

Background:

Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals.

Aims:

The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data.

Settings and Design:

Sixty subjects aged 20–85 years were included in the study.

Materials and Methods:

For each tooth, mid-sagittal, mid-coronal, and three axial sections—cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root—were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth.

Statistical Analysis Used:

All statistical analyses were performed using an SPSS 17.0 software program.

Results and Conclusions:

Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation (r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level.

Dental Patterns in Peruvians: A Panoramic Radiography Study

The dental pattern is defined as the combination of distinct codes assigned to describe specific tooth conditions including virgin, missing, and restored teeth that comprise the complete dentition or from discrete groups of teeth. This pattern can be then compared to the dentition of individual/s in an attempt to determine positive identification. The aims of the present investigation were to study and determine the diversity of dental patterns in Peruvian citizens based on a sample of panoramic radiographs. Digital panoramic radiographs of 900 adult Peruvian patients (450 female and 450 male) were evaluated to determine the dental patterns. The most frequent dental patterns found in the complete dentition, maxillae, upper-anterior and lower-anterior sextants were all-virgin-teeth (0.3%), all-extracted teeth (1.9%), all-virgin teeth (1%) and all-virgin-teeth (34.2% and 72.3%) respectively. The diversity was calculated by the use of the Simpson's diversity index, the resulting values for the full-dentition, maxilla and mandible were over the 99.8% value and were similar to those previously reported in the scientific literature. This study demonstrates the positive benefit of dental patterns in the process of identification. Additionally a combination of codes is proposed that could prove useful in cases where a better radiographic description is required.

Extension of the frontal sinus into the roof of the optic canal: a cadaveric case report

This case reports a bilateral asymmetrical posterior extension of the frontal sinuses into the orbital roof with an unusual expansion into the roof of the optic canal in a 55-year-old male cadaver. The posterior extensions of the sinus were lined by mucoperiosteum and were separated from the underlying orbital contents and optic nerve by a thin plate of bone. This knowledge of an unusual anatomic variation of the frontal sinus may help understand better the ocular and intracranial complications associated with frontal sinus pathologies.

Human identification through frontal sinus 3D superimposition: Pilot study with Cone Beam Computer Tomography

As a unique anatomical feature of the human body, the frontal sinus morphology has been used for identification of unknown bodies with many techniques, mostly using 2D postero-anterior X-rays. With the increase of the use of Cone-Beam Computer Tomography (CBCT), the availability of this exam as ante-mortem records should be considered. The purpose of this study is to establish a new technique for frontal sinus identification through direct superimposition of 3D volumetric models obtained from CBCT exam, by testing two distinct situations. First, a reproducibility test, where two observers independently rendered models of frontal sinus from a sample 20 CBCT exams and identified them on each other's list. In the second situation, one observer tested the protocol and established on different exams of three individual. Using the open source DICOM viewer InVesallius(®) for rendering, Mesh Lab(®,) for positioning the models and CloudCompare for volumetric comparison, both observers matched cases with 100% accuracy and the level of coincidence in a identification situation. The uniqueness of the frontal sinus topography is remarkable and through the described technique, can be used in forensic as an identification method whenever both the sinus structure and antemortem computer tomography is available.

Personal Identification in Forensic Science Using Uniqueness of Radiographic Image of Frontal Sinus

Frontal sinus pattern matching is a useful means of forensic identification. By the use of radiographs forensic scientists have recognized that there are diverse anatomical variations in the structure of the frontal sinus. Radiographs are a diagnostic tool, widely used in dental practices, hospitals and other health disciplines. Most health institutions possess the facility to store radiographs over long periods of time. Frontal sinus pattern matching technique can be applied in cases where ante mortem frontal sinus radiographs are available and dental matching cannot be carried out. Frontal sinus pattern matching technique may also be used to corroborate identifications based on other techniques such as fingerprints, teeth, or circumstantial evidence. The present study was carried out to assess the effectiveness of using the radiographic image of the frontal sinus for personal identification in studied population group. The results concluded that the appearance of the radiographic image of the frontal sinus is unique for each individual. On this evidence it is proposed that frontal sinus pattern matching can be used for personal identification when other methods have failed.

Determination of sex: interest of frontal sinus 3D reconstructions

Frontal sinuses (FSs) have been studied in radiology, anthropology, and forensic anthropology. This study aimed to determine whether it was possible to predict the age and sex of an individual using FS volume. Sixty-nine anonymized CT scans were imported to MIMICS 10.01(®) software (Materialise N.V.), and each FS volume was calculated in mm(3) . There was an absence of significant difference between right and left FS volume (p = 0.173) and an absence of correlation between age and FS volume (Pearson's test; p = 0.705). Sexual dimorphism was significantly different (p = 0.001). However, the most discriminant datum for determining sex was found to be the total FS volume (sum of an individual's right and left FS volumes) with linear discriminant Fisher's function coefficients of -2.759 for the male group and -1.275 for the female group. With this model, 72.5% of our sample was correctly classified according to sex.

A note on digital dental radiography in forensic odontology

Digital dental radiography, intraoral and extraoral, is becoming more popular in dental practice. It offers convenience, such as lower exposure to radiation, ease of storing of images, and elimination of chemical processing. However, it also has disadvantages and drawbacks. One of these is the potential for confusion of the orientation of the image. This paper outlines one example of this, namely, the lateral inversion of the image. This source of confusion is partly inherent in the older model of phosphor storage plates (PSPs), as they allow both sides to be exposed without clue to the fact that the image is acquired on the wrong side. The native software allows digital manipulation of the X-ray image, permitting both rotation and inversion. Attempts to orientate the X-ray according to the indicator incorporated on the plate can then sometimes lead to inadvertent lateral inversion of the image. This article discusses the implications of such mistakes in dental digital radiography to forensic odontology and general dental practice.

Radiomorphometric analysis of frontal sinus for sex determination

Context:

Sex determination of unknown individuals carries crucial significance in forensic research, in cases where fragments of skull persist with no likelihood of identification based on dental arch. In these instances sex determination becomes important to rule out certain number of possibilities instantly and helps in establishing a biological profile of human remains.

Aims:

The aim of the study is to evaluate a mathematical method based on logistic regression analysis capable of ascertaining the sex of individuals in the South Indian population.

Settings and Design:

The study was conducted in the department of Oral Medicine and Radiology.

Methods and Material:

The right and left areas, maximum height, width of frontal sinus were determined in 100 Caldwell views of 50 women and 50 men aged 20 years and above, with the help of Vernier callipers and a square grid with 1 square measuring 1mm² in area.

Statistical analysis used:

Student's t-test, logistic regression analysis.

Results:

The mean values of variables were greater in men, based on Student's t-test at 5% level of significance. The mathematical model based on logistic regression analysis gave percentage agreement of total area to correctly predict the female gender as 55.2%, of right area as 60.9% and of left area as 55.2%.

Conclusion:

The areas of the frontal sinus and the logistic regression proved to be unreliable in sex determination. (Logit = 0.924 - 0.00217 × right area).

Age estimation by measuring open apices of lower erupted teeth in 12-16 years olds by radiographic evaluation

The purpose of this study was to estimate chronological age from panoramic radiographs by measuring open apices of seven right or left mandibular teeth in children of South Indian origin. A total of 101 male and female patients aged between 12 and 16 years were selected. The panoramic radiographs of the patient were indirectly digitised. The variables N0, x3, x4, x5, x6, x7 and s were measured using a computer-aided drafting program. Statistical analysis was performed to derive a regression equation for estimation of age. Two variables x3 and x7 contributed significantly to the fit, yielding the following linear regression formula: Age = 16.025-9.445 (x7) + 1.620 (x3). Statistical analysis indicated that the regression equation explained 97.5% of total variance (R(2) = 0.975). The median of the residuals was -0.0348 years with an interquartile range (IQR) of 0.2520 years. The derived regression equations from these variables can serve as an invaluable tool in estimating the age of children between 12 and 16 years of South Indian origin.

A post-processing technique for cranial CT image identification

OBJECTIVE

A major challenge in radiographic identification is the inconsistent orientation between clinical (ante-mortem, AM) and post-mortem (PM) radiographs. The objectivity and accuracy of radiological identification would be greatly enhanced by post-processing techniques that allow quantitative comparison of PM CT data in the same orientation as the AM CT data.

METHODS

We applied a post-processing technique to reposition a multislice computed tomography (MSCT) scan for spatial registration with a CT radiograph from the same patient. A second set of MSCT images from different individuals served as the non-matched control group. The consistency in radiographic positioning eliminated subjectivity in the comparison and identification process because the radiograph superposition provided objective evidence that confirmed the identification with fine detail.

RESULTS

A quantitative comparison with statistical validation was achieved by measuring a set of 14 landmarks from the images. Discrimination of identity based on logistic regression analysis of the earlier CT patient scans (the AM group) versus subsequent MSCT scans (the PM group) was objective and reliable.

CONCLUSION

This quantitative comparison depends less on subjective judgment and the experience of the examiner, and so may meet legal standards.

Accuracy and reliability of cone beam computed tomography of the jaws for comparative forensic identification: a preliminary study

Conventional computed tomography is an emerging modality in forensic identification but is not sufficiently accurate for use in dental identification primarily because of problems with metallic dental restoration-induced streak artifact. In this study, the accuracy and reliability of recording forensic information from cone beam computed tomography (CBCT) scans of the jaws when compared to conventional panoramic radiographs has been analyzed under experimental conditions. Information could be recorded with near-perfect repeatability and reproducibility. Information could also be recorded accurately, the sensitivity being 96.6% (95% CI, 95.1-98.1) and specificity being 98.4% (95% CI, 96.2-100). The metal dental restoration-induced streak artifact was at a level that permitted, in most cases, accurate observations. This is considered an important step in validating CBCT as a tool in comparative dental identification of bodies. It may have a role in mass fatalities and in chemical, biological, radiological, and nuclear incidents, but further studies are required to assess the feasibility of this.

Use of frontal sinus and nasal septum patterns as an aid in personal identification: A digital radiographic pilot study

OBJECTIVES

To examine and classify the variations in the pattern of frontal sinus and nasal septum as observed on the posterior anterior Cephalometric radiographs, and to propose the possible use of the same in personal identification.

MATERIALS AND METHODS

This study was conducted on 50 individuals visiting the department, whose age ranged from 25 to 50 years. The radiographs of 25 males and 25 females were recorded using a Kodak 8000 C and Dental Imaging Software Viewer 6.3.4. Frontal sinus (symmetry and lobulations) and nasal septum patterns (deviations) were observed and classified.

RESULTS

Frontal sinus symmetry was observed in 29 (58%) individuals and asymmetry was observed in 16 (32%). Frontal sinuses were absent (bilateral aplasia) in two individuals (4%). Unilateral aplasia was seen in three individuals (6%). Straight nasal septum was seen in 11 (22%), right deviation in 21 (42%), and left deviation in 15 (30%) individuals. Sigmoid was seen in one male (2%), reverse sigmoid in one male (2%), and other pattern type in one female (2%). Both frontal sinus and nasal septum patterns were assessed together for each individual. Out of 50 individuals, 41 unique combinations of frontal sinus and nasal septum were found. However, there were nine individuals whose patterns matched one of the patterns of the 41 individuals.

CONCLUSION

We observed that the frontal sinus and nasal septum patterns had considerable individual variation. A combined use of both the patterns, as observed on the radiographs, could serve as an adjunct to other methods of personal identification.

Dental identification system based on unwrapped CT images

Dental comparison of postmortem (PM) and ante-mortem (AM) radiographs provides one of the best avenues for the forensic identification of human remains. Nevertheless conventional dental comparison is labor-intensive, subjective, and has several inherent drawbacks. This paper presents a semi-automated image analysis system designed to assist the forensic dentist with the task of identifying human remains. This system overcomes the drawbacks of conventional dental comparison because it is based on the comparison of radiograph-like images reconstructed from PM computed tomography (CT) data with AM digitized conventional radiographs. The efficacy of the system is demonstrated using 4 dental CT data sets and 32 digitized bitewing radiographs obtained from routine clinical practice.

Assessing forensic applications of the frontal sinus in a Chinese Han population

The frontal sinus is an important tool of personal identification. To assess the forensic applications of the frontal sinus patterns in a Chinese Han population, 198 individuals were analyzed. 165 individuals who have the frontal sinus were observed in this population, and 12 parameters of the frontal sinus were observed according to Yoshino's method. The same combined code was found in three persons from our samples. The unilateral frontal sinus scalloped with one arcade has few parameters applied to personal identification, and shows the poorer discrimination power. These parameters showed better discrimination power in our population, and could be applied to personal identification.

Comparison of two methods of dental age estimation in 7-15-year-old Malays

BACKGROUND

Numerous methods of age estimation have been proposed. The Demirjian method is the most frequently used, which was first applied in a French Canadian population in 1973. The Willems method is a modification of the above and was applied in a Belgian population in 2002.

OBJECTIVES

The objectives of this study were to test the applicability of the two methods, namely Demirjian and Willems, for age estimation in a Malay population, and to find the correlation between body mass index and the difference between the dental age and the chronological age.

MATERIALS AND METHODS

A cross-sectional study involving 214 boys and 214 girls, selected by a simple stratified random sampling method was carried out. The orthopantomograph was used to score the seven left mandibular teeth, and the calculated maturity score was used to obtain the Demirjian dental age. Willems dental age was estimated using the tables proposed in the Willems method. Results. The Demirjian method overestimated the age by 0.75 and 0.61 years, while the Willems method overestimated the age by 0.55 and 0.41 years among boys and girls, respectively. In boys, the body mass index was significantly correlated to the difference in age using the Willems method.

CONCLUSION

Further modification of either method is indicated for dental age estimation among the Malay population.

The forensic importance of frontal sinus radiographs

The identification of unidentified human remains through the comparison of antemortem and postmortem radiographs has found wide acceptance in recent years. Reported here is the forensic case of an unidentified adult male who had died as the result of a traffic accident, after which the body was identified by matching images of ante- and postmortem radiographs of the frontal sinus. A general discussion on identification using frontal sinus radiographs is presented, highlighting the reliability of this method, in reference to the uniqueness of the frontal sinus in humans. However, it also notes a few difficulties, especially in reference to the X-ray technique in cases where antemortem radiographs are available and a potentially larger number of anatomical, pathological or traumatic features are present. The comparison of frontal sinus outlines is recommended when it may become necessary to provide quantitative substantiation for forensic identification based on these structures.

The Use of Geographic Information Systems as a Forensic Tool to Investigate Sources of Marine Mammal Entanglement in Fisheries

Commercial fisheries represent a significant anthropogenic threat to marine mammal survival. Causes of marine mammal mortality are commonly determined by detailed necropsies of stranded carcasses. Gross evidence of entanglement in a fishery might include gear attached to the body, internal indications of asphyxiation and trauma, or gear markings on the epidermis. As gear is often fishery-specific, wound patterns on the epidermis that are created by entanglements in fishing gear may serve to identify possible sources of mortality. For this study, tools within the Environmental Systems Research Institute, Inc. (ESRI) ArcMap GIS software were used to create maps that outline impressions that fishing gear can leave on the epidermis of entangled marine mammals. These maps can subsequently be used to identify possible sources of fishery entanglement for the many marine mammals that wash ashore without gear attached to their carcass. Entanglement wound patterns can be visually compared with fishing gear characteristics; however, differences in scale and image quality can introduce subjectivity that might hinder source identification. The technique described herein provides an objective way to outline the unique characteristics of fishing gear and their associated wounds on entangled marine mammals. Additionally, spatial relationships are preserved as the maps are adjusted to varying scales. Whereas the initial protocol required time-consuming digitization of the outline and visual determination of the pattern interface, this new, semiautomated technique saves analyst effort and minimizes error.

Antemortem Records of Forensic Significance Among Edentulous Individuals

The identification of edentulous individuals is problematic due to poor provision of labelled dental prostheses. Dental records may still provide useful information for odontologists in the comparative identification process. The purpose of this study was to determine the level of forensically significant information contained within the dental records of a population of denture wearers attending the University of Manchester School of Dentistry. Two hundred and two dental records were examined and a proforma completed. The mean age of the patients was 72 years. Medical history were absent in 4% of all records and only 67.8% of the written records were rated as good. Thirty-two percent of the records contained one or more panoramic radiographs but 30% of these were over 3 years old rendering their usefulness in identification procedures questionable. In total only 18% of the examined records contained antemortem information that would enable identification. These data suggest that the process of denture marking is an essential in order to ensure that the identification of this population can be undertaken expediently by dental means.