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A systematic review of odontological sex estimation methods
Cezar Capitaneanu, Guy Willems, Patrick Thevissen
ABSTRACT
Background: In human identification sex estimation plays an important role in the search for ante-mortem data.
Aim: To systematically review studies describing and testing/ validating methods of odontological sex estimation. The set research question was: What odontological sex estimation method is the most accurate?
Materials and methods: An electronic search until November 29th 2016 was performed in 5 databases: MEDLINE/PubMed, Cochrane, SciELO, LILACS and Grey literature. The PRISMA guidelines were used. Studies were assessed and included based on the reported data. In particular data criteria were set regarding the considered population, sample size, age range, sex estimation method, type of statistical analysis and study outcome. The extracted data enabled to classify the included studies. Meta-analysis was used to compare the study outcomes per obtained study group.
Results: The established search string detected 4720 studies. 103 were considered eligible after review of title, abstract and full-text. The odontological sex estimation methods were classified based on dental metric and non-metric measurements (n=65), cephalometric analysis (n=13), frontal and maxillary sinuses (n=5), cheiloscopy (n=4), palatal features (n=3) and biochemical analysis of teeth (n=13). Teeth measurements for sex estimation were mainly performed on casts (n=34), followed by skeletal remains (n=13), medical imaging (n=5), intraoral measurements/photography (n=4), and cascades of the above (n=4).
Conclusion: The variety of published odontological sex estimation methods highlights the importance of sex estimation in human identification. Biochemical analysis of teeth proved to be the most accurate method, but in forensic practice, a need to select the most appropriate evidence based odontological sex estimation method exists.
(J Forensic Odontostomatol 2017;35;2:1-19)
Prevalence of agenesis of frontal sinus in human skulls with metopism
Lorena Batista Sandre, Mayara B. Vandal Mundim-Picoli, Fernando Fortes Picoli, Livia Graziele Rodrigues, Juliano Martins Bueno, Rhonan Ferreira da Silva
Abstract
Background: The frontal bone is an anatomical structure of the skull separated by the metopic suture in the childhood. The scientific literature indicates that metopic suture consolidates with closure in the early stages of life. Metopism is the term used to describe a metopic suture that persists up to the adulthood. Persistent metopic suture is associated potentially with the agenesis of the frontal sinus.
Aim: To investigate the prevalence of absent frontal sinuses in dry skulls with metopism.
Materials and methods: The present study was performed after the approval of the local Committee of Ethics in Research. The sample consisted of dry skulls (n=245), aging between 17 and 50 years old, of the Forensic Medical Institute of Goiânia, Brazil. The skulls underwent anthropological exam in the search for metopism. Radiographic exam was performed in the skulls with metopism to verify the presence or absence of the frontal sinus. The radiographic assessment was performed with a Mobile DaRt Evolution device (Shimadzu, Kyoto, Japan) with protocol set in 64 kV and 16 mA).
Results: From the 245 dry skulls, 17 presented metopism. The length of the metopic suture in the skulls, considering the distances between nasio and bregma craniometric landmarks, ranged between 114 mm and 137 mm. Radiographic exams were performed on 16 skulls (one skull was not analysed radiographically because of extensive destruction). Only one skull (6.25%) had the frontal sinus absent. Besides the agenesis, the present study also found four (12.5%) skulls with aplasia and eight (25.0%) hyperplasia of the frontal sinus in dry skulls with metopism.
Conclusion: The present study found a low prevalence rate of the agenesis of frontal sinuses in dry skulls with metopism.
(J Forensic Odontostomatol 2017;35;2:20-27)
Extra-oral dental radiography for disaster victims using a flat panel X-ray detector and a hand-held X-ray generator
Maki Ohtani, Toru Oshima , Sohtaro Mimasaka
Abstract
Background: Forensic odontologists commonly incise the skin for post-mortem dental examinations when it is difficult to open the victim’s mouth. However, it is prohibited by law to incise dead bodies without permission in Japan. Therefore, we attempted using extra-oral dental radiography, using a digital X-ray equipment with rechargeable batteries, to overcome this restriction.
Materials and methods: A phantom was placed in the prone position on a table, and three plain dental radiographs were used per case: “lateral oblique radiographs” for left and right posterior teeth and a “contact radiograph” for anterior teeth were taken using a flat panel X-ray detector and a hand-held X-ray generator. The resolving power of the images was measured by a resolution test chart, and the scattered X-ray dose was measured using an ionization chamber-type survey meter.
Results: The resolving power of the flat panel X-ray detector was 3.0 lp/mm, which was less than that of intra-oral dental methods, but the three extra-oral plain dental radiographs provided the overall dental information from outside of the mouth, and this approach was less time-consuming. In addition, the higher dose of scattered X-rays was laterally distributed, but the dose per case was much less than that of intra-oral dental radiographs.
Conclusion: Extra-oral plain dental radiography can be used for disaster victim identification by dental methods even when it is difficult to open the mouth. Portable and rechargeable devices, such as a flat panel X-ray detector and a hand-held X-ray generator, are convenient to bring and use anywhere, even at a disaster scene lacking electricity and water.
(J Forensic Odontostomatol 2017;35;2:28-34)
Semi-automatic forensic approach using mandibular midline lingual structures as fingerprint: a pilot study
Eman Shaheen, Bassant Mowafy, Constantinus Politis, Reinhilde Jacobs
Abstract
Background: Previous research proposed the use of the mandibular midline neurovascular canal structures as a forensic finger print. In their observer study, an average correct identification of 95% was reached which triggered this study.
Aim: To present a semi-automatic computer recognition approach to replace the observers and to validate the accuracy of this newly proposed method.
Materials and methods: Imaging data from Computer Tomography (CT) and Cone Beam Computer Tomography (CBCT) of mandibles scanned at two different moments were collected to simulate an AM and PM situation where the first scan presented AM and the second scan was used to simulate PM. Ten cases with 20 scans were used to build a classifier which relies on voxel based matching and results with classification into one of two groups: “Unmatched” and “Matched”. This protocol was then tested using five other scans out of the database. Unpaired t-testing was applied and accuracy of the computerized approach was determined.
Results: A significant difference was found between the “Unmatched” and “Matched” classes with means of 0.41 and 0.86 respectively. Furthermore, the testing phase showed an accuracy of 100%.
Conclusion: The validation of this method pushes this protocol further to a fully automatic identification procedure for victim identification based on the mandibular midline canals structures only in cases with available AM and PM CBCT/CT data.
(J Forensic Odontostomatol 2017;35;2:35-41)
An automated technique to stage lower third molar development on panoramic radiographs for age estimation: a pilot study
Jannick De Tobel, Purnima Radesh, Dirk Vandermeulen, Patrick W. Thevissen
Abstract
Background: Automated methods to evaluate growth of hand and wrist bones on radiographs and magnetic resonance imaging have been developed. They can be applied to estimate age in children and subadults. Automated methods require the software to (1) recognise the region of interest in the image(s), (2) evaluate the degree of development and (3) correlate this to the age of the subject based on a reference population. For age estimation based on third molars an automated method for step (1) has been presented for 3D magnetic resonance imaging and is currently being optimised (Unterpirker et al. 2015).
Aim: To develop an automated method for step (2) based on lower third molars on panoramic radiographs.
Materials and methods: A modified Demirjian staging technique including ten developmental stages was developed. Twenty panoramic radiographs per stage per gender were retrospectively selected for FDI element 38. Two observers decided in consensus about the stages. When necessary, a third observer acted as a referee to establish the reference stage for the considered third molar. This set of radiographs was used as training data for machine learning algorithms for automated staging. First, image contrast settings were optimised to evaluate the third molar of interest and a rectangular bounding box was placed around it in a standardised way using Adobe Photoshop CC 2017 software. This bounding box indicated the region of interest for the next step. Second, several machine learning algorithms available in MATLAB R2017a software were applied for automated stage recognition. Third, the classification performance was evaluated in a 5-fold cross-validation scenario, using different validation metrics (accuracy, Rank-N recognition rate, mean absolute difference, linear kappa coefficient).
Results: Transfer Learning as a type of Deep Learning Convolutional Neural Network approach outperformed all other tested approaches. Mean accuracy equalled 0.51, mean absolute difference was 0.6 stages and mean linearly weighted kappa was 0.82.
Conclusion: The overall performance of the presented automated pilot technique to stage lower third molar development on panoramic radiographs was similar to staging by human observers. It will be further optimised in future research, since it represents a necessary step to achieve a fully automated dental age estimation method, which to date is not available.
(J Forensic Odontostomatol 2017;35;2:42-54)
Age estimation by facial analysis based on applications available for smartphones
Ana L. Rezende Machado, Thais Uenoyama Dezem, Aline Thais Bruni, Ricardo H. Alves da Silva
Abstract
Background: Forensic Dentistry has an important role in the human identification cases and, among the analyses that can be performed, age estimation has an important value in establishing an anthropological profile. Modern technology invests for new mechanisms of age estimation: software apps, based on special algorithms, because there is not interference based on personal knowledge, cultural and personal experiences for facial recognition.
Materials and methods: This research evaluated the use of two different apps: “How Old Do I Look? – Age Camera” and “How Old Am I? – Age Camera, Do You Look Like in Selfie Face Pic?”, for age estimation analysis in a sample of 100 people (50 females and 50 males). Univariate and multivariate statistical methods were used to evaluate data.
Results: A great reliability was seen when used for the male volunteers. However, for females, no equivalence was found between the real age and the estimated age.
Conclusion: These applications presented satisfactory results as an auxiliary method, in male images.
(J Forensic Odontostomatol 2017;35;2:55-65)
Are cervical vertebrae suitable for age estimation?
Bianca Gelbrich, Miriam Fischer, Angelika Stellzig-Eisenhauer, Götz Gelbrich
Abstract
Background: The ability of cervical vertebrae (CV) staging to contribute in forensic age estimation is being discussed controversially. The large variability of CV geometries in the end stage of development might be the reason for not reaching a performance competitive to hand or third molar methods. Here we study the geometry of adult CV and demonstrate that the description of their “typical” appearance is often not met.
Materials and methods: Lateral cephalograms from clinical routine of 320 subjects aged 20 years or above (median 24 years, 52% female) were evaluated. The criteria for the end stage of CV development (Hassel-Farman, Baccetti) were examined by assessing them in terms of metric measurements: (1) rectangular shape of C3/C4, (2) at least one of the height-width ratios of C3/C4 >1 (both not <1), (3) significant concavities at the inferior margin of C2, C3 and C4. Metric data of the adults were also compared to those of 100 children aged 8-10 years (50% female).
Results: Adult CV often violated the criteria of rectangular shape (44% C3, 36% C4), of height-width ratio (16% C3, 35% C4) and inferior concavity (10% C2, 10% C3, 19% C4). All of the criteria for adult CV were fulfilled in only 24% of the subjects (95%CI 19-28%). The variability of measures of the CV shapes was large; e.g., the 95% reference ranges for the height-width ratios were 0.81-1.19 (C3) and 0.77-1.14 (C4). There was a material overlap of ranges of CV measures of adults and children.
Conclusion: While hand bones and teeth have well-defined appearances in the end stage of development, adult CV have a large biological variance of shapes; it is hard to define their “typical” appearance. Moreover, measures of CV geometry do not strictly separate adults from children. These facts might reason the limited usefulness of CV in age estimation.
(J Forensic Odontostomatol 2017;35;2:66-78)
A radiographic study estimating age of mandibular third molars by periodontal ligament visibility
Mohsin A. Chaudhary, Helen M. Liversidge
Abstract
Background: Visibility of the periodontal ligament of mandibular third molars (M3) has been suggested as a method to estimate age.
Aim: To assess the accuracy of this method and compare the visibility of the periodontal ligament in the left M3 with the right M3. The sample was archived panoramic dental radiographs of 163 individuals (75 males, 88 females, age 16-53 years) with mature M3’s.
Materials and methods: Reliability was assessed using Kappa. Accuracy was assessed by subtracting chronological age from estimated age for males and females. Stages were cross-tabulated against age stages younger than and at least 18 and 21 years of age. Stages were compared in the left M3 and right M3.
Results: Analysis showed excellent intra-observer reliability. Mean difference between estimated and chronological ages was 7.21 years (SD 5.16) for left M3 and 7.69 (SD 6.08) for right M3 in males and 6.87 (SD 5.83) for left M3 and 8.61 (SD 6.58) for right M3 in females. Minimum ages of stages 0 to 2 were younger than previously reported, despite a small sample of individuals younger than 18. The left and right M3 stage differed in 46% of the 85 individuals with readings from both side and estimated age differed from -10.5 to 12.2 years between left and right.
Conclusion: Accuracy of this method was between 6 and 8 years with an error of 5 to 6 years. The number of individuals with mature M3 apices younger than 18 years was small. The stage of visibility of the periodontal ligament differed between left and right in almost half of our sample with both teeth present. Our findings question the use of this method to estimate age or to discriminate between age younger and at least 18 years.
(J Forensic Odontostomatol 2017;35;2:79-89)
Periodontal Ligament Visibility (PLV): validation of PLV to determine adult status
Victoria S. Lucas, Fraser Mc Donald, Mano Andiappan, Graham Roberts
Abstract
Background: Gradual obliteration of the Periodontal Ligament Visibility (PLV) of lower third molars indicates increasing age. This is used to help determine whether or not an age disputed subject is above or below the 18 year threshold.
Aim: The main focus was to determine, in test subjects of known age, whether the PLV system used ‘blind’ is able to reliably indicate whether the subject was a child (age <18 years) or adult (age >18).
Materials and methods: A total of 250 normal subjects in the age range 16 to 26 years, from the archives of Guy’s Hospital in London, UK, were used to validate the system of PLV. The radiographic assessment of PLV1 was used to categorise four grades of PLV.
Results: It was found that for both females and males PLV-C and PLV-D gave very high probabilities (p = 1.000) of the test subjects being of adult status.
Conclusion: Periodontal Ligament Visibility has the potential to play an important part in the assessment of age disputed asylum seekers who look adult and claim to be children.
(J Forensic Odontostomatol 2017;35;2:90-96)
A radiographic study of the mandibular third molar root development in different ethnic groups
Helen M.Liversidge, Kalaiarasu Peariasamy, Morenike Oluwatoyin Folayan, Abiola Adetokunbo Adeniyi, Papa Ibrahima Ngom, Yuko Mikami, Yukie Shimada, Kazuto Kuroe, Ingun F.Tvete, Sigrid I. Kvaal
Abstract
Background: The nature of differences in the timing of tooth formation between ethnic groups is important when estimating age.
Aim: To calculate age of transition of the mandibular third (M3) molar tooth stages from archived dental radiographs from sub-Saharan Africa, Malaysia, Japan and two groups from London UK (Whites and Bangladeshi).
Materials and methods: The number of radiographs was 4555 (2028 males, 2527 females) with an age range 10-25 years. The left M3 was staged into Moorrees stages. A probit model was fitted to calculate mean ages for transitions between stages for males and females and each ethnic group separately. The estimated age distributions given each M3 stage was calculated. To assess differences in timing of M3 between ethnic groups, three models were proposed: a separate model for each ethnic group, a joint model and a third model combining some aspects across groups. The best model fit was tested using Bayesian and Akaikes information criteria (BIC and AIC) and log likelihood ratio test.
Results: Differences in mean ages of M3 root stages were found between ethnic groups, however all groups showed large standard deviation values. The AIC and log likelihood ratio test indicated that a separate model for each ethnic group was best. Small differences were also noted between timing of M3 between males and females, with the exception of the Malaysian group. These findings suggests that features of a reference data set (wide age range and uniform age distribution) and a Bayesian statistical approach are more important than population specific convenience samples to estimate age of an individual using M3.
Conclusion: Some group differences were evident in M3 timing, however, this has some impact on the confidence interval of estimated age in females and little impact in males because of the large variation in age.
(J Forensic Odontostomatol 2017;35;2:97-108)
Comparisons between skeletal and dental age assessment in unaccompanied asylum seeking children
Sigrid I. Kvaal, Marion Haugen
Abstract
Background: For children with disputed date of birth, age assessments based on skeletal and dental development are recommended.
Aim: The aim of this retrospective study was to compare and contrast the results of age assessments from these two methods performed on unaccompanied asylum seeking children in Norway. In addition the aim of the analysis was to see if the skeletal age assessment from hand-wrist was operator sensitive.
Materials and methods: Age assessments performed from January 2010 to December 2014 were analysed. Skeletal development of hand-wrist was graded according to Greulich and Pyle (1959). Dental development of the wisdom teeth was scored on orthopantomograms according to Moorrees, Fanning and Hunt (1963) and age assessed from tables published by Liversidge (2008) and Haavikko (1970). In the statistical analysis agreement between the two age assessments was defined according to the asylum seeker’s age being assessed to be older or younger than 18 years. The statistical analysis included 3333 boys and 486 girls.
Results: The agreement was 83% for boys and 79% for girls. Approximately 70% of the boys and girls were 18 years or older by both methods. It was more common that the skeletal age was assessed older than 18 years and dental age younger than 18 years for both genders. It could be demonstrated that the age assessment based on skeletal maturation was not operator sensitive.
Conclusion: The analyses demonstrate that there is good agreement between the two age assessments, but a method to combine the results would increase the reliability of the age assessments.
(J Forensic Odontostomatol 2017;35;2:109-116)
Forensic age estimation based on development of third molars: a staging technique for magnetic resonance imaging
Jannick De Tobel, Inès Phlypo, Steffen Fieuws, Constantinus Politis, Koenraad L. Verstraete. Patrick W. Thevissen
Abstract
Background: The development of third molars can be evaluated with medical imaging to estimate age in subadults. The appearance of third molars on magnetic resonance imaging (MRI) differs greatly from that on radiographs. Therefore a specific staging technique is necessary to classify third molar development on MRI and to apply it for age estimation.
Aim: To develop a specific staging technique to register third molar development on MRI and to evaluate its performance for age estimation in subadults.
Materials and methods: Using 3T MRI in three planes, all third molars were evaluated in 309 healthy Caucasian participants from 14 to 26 years old. According to the appearance of the developing third molars on MRI, descriptive criteria and schematic representations were established to define a specific staging technique. Two observers, with different levels of experience, staged all third molars independently with the developed technique. Intra- and inter-observer agreement were calculated. The data were imported in a Bayesian model for age estimation as described by Fieuws et al. (2016). This approach adequately handles correlation between age indicators and missing age indicators. It was used to calculate a point estimate and a prediction interval of the estimated age. Observed age minus predicted age was calculated, reflecting the error of the estimate.
Results: One-hundred and sixty-six third molars were agenetic. Five percent (51/1096) of upper third molars and 7% (70/1044) of lower third molars were not assessable. Kappa for inter-observer agreement ranged from 0.76 to 0.80. For intra-observer agreement kappa ranged from 0.80 to 0.89. However, two stage differences between observers or between staging sessions occurred in up to 2.2% (20/899) of assessments, probably due to a learning effect. Using the Bayesian model for age estimation, a mean absolute error of 2.0 years in females and 1.7 years in males was obtained. Root mean squared error equalled 2.38 years and 2.06 years respectively. The performance to discern minors from adults was better for males than for females, with specificities of 96% and 73% respectively.
Conclusion: Age estimations based on the proposed staging method for third molars on MRI showed comparable reproducibility and performance as the established methods based on radiographs.
(J Forensic Odontostomatol 2017;35;2:117-140)
The age estimation practice related to illegal unaccompanied minors immigration in Italy
Francesco Pradella, Vilma Pinchi, Martina Focardi, Rossella Grifoni, Marco Palandri, Gian-Aristide Norelli
Abstract
The migrants arrived to the Italian coasts in 2016 were 181.436, 18% more than the previous year and 6% more than the highest number ever since. An “unaccompanied minor” (UAM) is a third-country national or a stateless person under eighteen years of age, who arrives on the territory of the Member State unaccompanied by an adult responsible for him/her whether by law or by the practice of the Member State concerned, and for as long as he or she is not effectively taken into the care of such a person; it includes a minor who is left unaccompanied after he/she entered the territory of the Member States.
As many as 95.985 UAMs applied for international protection in an EU member country just in 2015, almost four times the number registered in the previous year. The UAMs arrived in Italy were 28.283 in 2016; 94% of them were males, 92% unaccompanied, 8% of them under 15; the 53,6% is 17; the individuals between 16 and 17 are instead the 82%. Many of them (50%), 6561 in 2016, escaped from the sanctuaries, thus avoiding to be formally identified and registered in Italy in the attempt to reach more easily northern Europe countries, since The Dublin Regulations (2003) state that the asylum application should be held in the EU country of entrance or where parents reside. The age assessment procedures can therefore be considered as a relevant task that weighs in on the shoulders of the forensic experts with all the related issues and the coming of age is the important threshold. In the EU laws on asylum, the minors are considered as one of the groups of vulnerable persons towards whom Member States have specific obligations. A proper EU common formal regulation in the matter of age estimation procedures still lacks. According to the Italian legal framework in the matter, a medical examination should have been always performed but a new law completely changed the approach to the procedures of age estimation of the migrant (excluding the criminal cases) with a better adherence to the notions and concepts of vulnerability and psychological and social maturity.
(J Forensic Odontostomatol 2017;35;2:141-148)
Forensic odontology education: from undergraduate to PhD – a Brazilian experience
Julia G. Dietrichkeit Pereira, Tamara S. Frontanilla Recalde, Paula Barreto Costa, Victor Jacometti, Luciana Vigorito Magalhães, Ricardo H. Alves Da Silva
Abstract
Background: Forensic Odontology is a topic present in the majority of Dental Schools in Brazil, and due to this reality, some universities develop activities related to undergraduate and graduate students, from the Dentistry course until the Ph.D. degree.
Aim: To present the education experience related to Forensic Odontology at School of Dentistry of Ribeirão Preto (USP – University of São Paulo), showing the strategies and activities in the different degrees (Dental course, Forensic Odontology Specialization Program, Specific Professional Training, Master, and Ph.D.).
Results: To the undergraduate students, many activities are developed in order to demonstrate all the possibilities that Forensic Dentistry allow, including theoretical and practical activities; in the Forensic Odontology Specialization Program, the dentists are trained to act as Forensic Odontologists in all its amplitude; in the Specific Professional Training, some courses are available, related to specific topics as DVI, Forensic Facial Reconstruction, Auditor in Dental Care Insurance and others; and in the Master and Ph.D. Programs, the professionals receive training in skills like teaching, research, student’s guidance and others.
Conclusion: In Brazil, Forensic Odontology is a well-known field in Dentistry and universities develop an important role in training a qualified workforce.
(J Forensic Odontostomatol 2017;35;2:149-156)
Day to day issues in the forensic identification practice related to illegal immigration in Italy
Vilma Pinchi, Martina Focardi, Francesco Pradella, Rossella Grifoni, Marco Palandri, Gian-Aristide Norelli
Abstract
The migratory flows to Europe from the African countries, Asia and Middle East, have hugely intensified in the recent years. In 2016, more than 98,000 out of a total of 260,000 migrants across the Mediterranean Sea arrived in Italy and in May 2017, the trend of arrivals is: Italy +576%; Greece -39% compared to previous years. Some migrants die before touching the sole of the European continent, during the crossing, often afforded with ships, made available by unscrupulous smugglers or criminal organizations, which are unsuitable for this type of transportation. The tremendous occurrence of migrant casualties during the Mediterranean Sea crossing remains underestimated and nobody, country officers or databank, can provide a reliable number of dead bodies in such a large and now, endemic phenomenon. Forensic officers, who intervened to examine migrants’ corpses, are ideally required to perform the usual activity and to answer the routine questions about the causes of death by detecting signs of possible crimes and body identification. In practice, several specific issues and limits challenge the activity of the forensic professionals addressed to ascertain both circumstances of death and possible related crimes and the identity of the corpses. Generally speaking, in case of examining up to a few dead bodies in Italy, a complete autopsy is performed, whilst, when several tens or hundreds of corpses are recovered, the lack of resources on one hand and clearer clues on incident, connected crimes, and cause of deaths on the other, push the public prosecutor to limit the request of complete autopsies. In some cases, the dead migrants were identified through visual recognition by relatives, friends, or travel companions. The DVI Interpol protocol is never completely applied to dead migrants for several reasons, mainly for the huge difficulties in retrieving AM data of the missing persons and for some limitations affecting both the primary and the secondary identifiers. The few chances of identification by dental data are further reduced by the systematic lack of an odontologist among the forensic teams charged of the PM; valuable dental data for body identification or for constructing the biological profile of the missing person (age, ancestry, country of provenance/residence, etc.) are likely to be overlooked.
This approach implies a clear disparity with the approach applied when corpses of citizens of the EU or other developed countries are involved and undergo identification. The dead migrants’ identification activity should be reconsidered for an improvement in the common international effort in accordance to an approach more respectful toward the legal rights and dignity of the dead migrants and their families.