Application and performance of artificial intelligence technology in forensic odontology - A systematic review

Forensic odontology (FO) mainly deals with the identification of the individual through the remains, which mainly includes teeth and jawbones. Artificial intelligence (AI) technology has proven to be a breakthrough in providing reliable information in decision making in forensic sciences. This systematic review aimed to report on the application and performance of AI technology in FO. The data was gathered through searching for the articles in the renowned search engines, which have been published between January 2000 - June 2020. QUADAS-2 was adopted for the risk of bias analysis of the included studies. AI technology has been widely applied in FO for identifying bite-marks, predicting mandibular morphology, gender determination, and age estimation. Most of these AI models are based on either artificial neural networks (ANNs) or convolutional neural networks (CNNs). The results of the studies are promising. Studies have reported that these models display accuracy and precision equivalent to that of the trained examiners. These models can be promising tools when identifying victims of mass disasters and as an additive aid in medico-legal situations.

Above or below 14 years? An orthopantomographic study based on chronological course of eruption of mandibular premolars and second molars in a sample of south Indian children

In the context of dental age assessment, two significant factors can be studied; tooth mineralisation and tooth emergence. Little is known about the role of a second molar eruption in forensic age estimation. This paper aims to contribute to forensic age estimation using an age threshold of 14 years, studying the eruption stages of permanent mandibular premolars and second molars. Totally 640 orthopantomograms (OPGs) of south Indian children, aged between 10 and 18 years, were evaluated using Olze et al. staging of tooth eruption stages (A-D). Spearman's rho correlation showed a strong, positive, and statistically significant correlation between the chronological age and the eruption stages of both sexes' teeth. Accuracy, sensitivity, specificity, likelihood ratios, and post-test probability values were calculated for all tested teeth. The best performance to discriminate individuals above or below 14 years showed stage D in second molars. The sensitivity varied between 89% and 94% and specificity between 75% and 84%, respectively. Receiver operating characteristic curve analysis revealed high diagnostic performance for stage D, with area under the ROC curve (AUC) values of 84% and 85% for tooth 37 and 85% and 83% for tooth 47 in males and females, respectively. In conclusion, it is possible to predict age over 14 years in south Indian children using tooth emergence stages from OPGs with a relatively high interobserver agreement and good diagnostic accuracy. However, there are some limitations and, therefore, must be used in conjunction with other methods.

Sex classification of first molar teeth in cone beam computed tomography images using data mining

OBJECTIVE

The teeth have been used as a supplementary tool for sex differentiation as they are resistant to post-mortem degradation. The present study aimed to develop a new novel informatics framework for predicting sex from linear tooth dimension measurements achieved from cone beam computed tomography (CBCT) images.

METHOD AND MATERIALS

A clinical workflow using different machine learning methods was employed to predict the sex in the present study. The CBCT images of 485 subjects (245 men and 240 women) were evaluated for sex differentiation. Nine parameters were measured in both buccolingual and mesiodistal aspects of the teeth. We applied our dataset to Naïve Bayesian (NB), Random Forest (RF), and Support Vector Machine (SVM) as classifiers for prediction. Genetic feature selection was used to discover real features associated with sex classification.

RESULTS

The 10-fold cross-validation results indicated that NB had higher accuracy than SVM and RF for sex classification. The genetic algorithm (GA) indicated that the model could fit the data without using the enamel thickness and pulp height. The average classification accuracy of our clinical workflow was 92.31 %.

CONCLUSION

The results showed that NB was the best method for sex classification. The application of the first molar teeth in sex prediction indicated an acceptable level of sexual classification. Therefore, these odontometric parameters can be applied as an additional tool for sex determination in forensic anthropology.

Root Dentin Translucency and Forensic International Dental Database: Methodology for estimation age-at-death in adults using single-rooted teeth

Estimation of the age-at-death in adults is essential when the identification of deceased persons with unknown identity is required in both humanitarian and judicial contexts. However, the methodologies and the results obtained can be questioned. Various efforts have been developed to adjust procedures to specific populations, always seeking the precision and accuracy of the methodologies. It is known that the estimation of the age-at-death in adults coexists with wide margins of error, due to several reasons, including but not limited to statistical problems, the size of the sample or the physiological process of aging. This research focuses on a degenerative indicator of the dentin (Root Dentin Translucency) and its combination with Periodontal Height (PH) following the Lamendin's technique for estimation of the age-at-death in adults. The main objective of this research was to demonstrate the applicability of a Bayesian model based on a Forensic International Dental Database (FIDB) that include Root Translucency Height (RTH) and PH as a method to age-at-death in adults. The conclusion of this research was that the combined both indicators become a generalizable age-at-death in adults model for all human populations, where the Bayesian method would offer optimal results in any population. In this way, those populations that do not have had the possibility of validating a specific procedure, now have the opportunity to apply a valid method for estimating age-at-death in adults to global scope.

Analysis of 100 most cited articles on forensic odontology

OBJECTIVES

Bibliometric analysis of best-cited papers brings awareness about the influential publications and trends in the literature on a particular topic. This will help not only the researchers and academicians but also the students for selecting quality landmark articles. With this view in mind a bibliometric analysis was performed to identify the 100 top-cited papers on Forensic Odontology (FO) in the literature.

MATERIALS AND METHODS

A search was performed using Scopus database in August 2019. The articles were further reviewed and basic standard information related to bibliometric analysis was recorded.

RESULTS

The 100 most cited articles were published from 1985 to 2014 (77% published after 2001). The most frequently cited article received 259 citations, whereas the least received 31 (mean citations 58.78 ± 33.14). There were 16 different journals with Forensic Science International having the most number of articles (n = 36). One author had 16 articles while 8 authors had 4 or more articles published in the top 100 list. Belgium was the country with most number of articles (n = 17) followed by United States (n = 16). In terms of document type, 87 were original research, 7 conference papers and 6 reviews. Five organizations funded 5 of the top 100 articles. Katholieke Universiteit Leuven, Belgium affiliated the most documents (n = 16). Majority of the papers were related to age estimation (46) followed by victim identification (30), mass disaster (9), bite mark analysis (8), sex determination (5), race determination (4), dental DNA analysis (3), palatal rugae pattern (2) and lip prints (1).

CONCLUSION

This is first of its kind citation analysis of the 100 most cited articles in the field of FO. The results of this paper will help the researchers, academicians and students for appropriate article referrals.

Application of intraoral scanner to identify monozygotic twins

BACKGROUND

DNA base identification is a proper and high specificity method. However, identification could be challenged in a situation where there is no database or the DNA sequence is almost identical, as in the case of monozygotic (MZ) twins. The aim of this study was to introduce a novel forensic method for distinguishing between almost identical MZ twins by means of an intraoral scanner using the 3D digital pattern of the human palate.

METHODS

The palatal area of 64 MZ twins and 33 same-sex dizygotic (DZ) twins (DZSS) and seven opposite-sex dizygotic twins (DZOS) were scanned three times with an intraoral scanner. From the scanned data, an STL file was created and exported into the GOM Inspect® inspection software. All scans within a twin pair were superimposed on each other. The average deviation between scans of the same subject (intra-subject deviation, ISD) and between scans of the two siblings within a twin pair (intra-twin deviation, ITD) was measured. One-sided tolerance interval covering 99% of the population with 99% confidence was calculated for the ISD (upper limit) and the ITD (lower limit).

RESULTS

The mean ISD of the palatal scan was 35.3 μm ± 0.78 μm. The calculated upper tolerance limit was 95 μm. The mean ITD of MZ twins (406 μm ± 15 μm) was significantly (p < 0.001) higher than the ISD, and it was significantly lower than the ITD of DZSS twins (594 μm ± 53 μm, p < 0.01) and the ITD of DZOS twins (853 μm ± 202 μm, p < 0.05).

CONCLUSION

The reproducibility of palatal intraoral scans proved to be excellent. The morphology of the palate shows differences between members of MZ twins despite their almost identical DNA, indicating that this method could be useful in forensic odontology.

Emulating Odontolegal Practice: A Paradigm Shift in the Dental Practice Laying More Emphasis on Dental Records-A Perspective and Contemporary Study with a Reality Check

Aim

This study was conducted to evaluate the knowledge and the awareness on odontolegal practice with more emphasis on significance of maintaining dental records by the oral health professionals.

Materials and methods

A cross-sectional study was carried out among 120 dental practitioners of Jammu and Kashmir, Himachal Pradesh, Delhi, Punjab, Gujarat, and Odisha. A questionnaire was designed to assess their practice and knowledge regarding the importance of maintenance of dental records and the knowledge about dental jurisprudence. Total 120 questionnaire samples were distributed among dental health professionals, and the data obtained were studied and formulated for significance of dental records.

Results

Feedback obtained was then analyzed. Seventy percentage of the dentists are not maintaining clinical records of their patients and 20% of the dentists acknowledged that they are not keeping or maintaining dental records like X-rays and cast models of their patients. Eighty percentage of dentists were not known to the ethical importance of dental record, i.e., for how long they have to maintain records of their patients and other details.

Conclusion

This study concludes that the oral health professionals lacked the knowledge and awareness about odontolegal aspects and the significance of maintaining dental records. It was observed that there was insufficient knowledge about medicolegal systems and there is a need to bring awareness and knowledge of the same in the dental fraternity.

Clinical significance

With the increasing use of medical insurance and subsequently mediclaims, negligence suits, scientific evaluation, and research purposes, and health planning, etc., the “dental records itself have evolved as a separate science and therefore needs to be considered in the curriculum for dental students as this would introduce the concept for application in their future practice, thus avoiding legal complications in the future.”

How to cite this article

Kaul B, Gupta S, Vaid V, et al. Emulating Odontolegal Practice: A Paradigm Shift in the Dental Practice Laying More Emphasis on Dental Records—A Perspective and Contemporary Study with a Reality Check. Int J Clin Pediatr Dent 2020;13(3):217–220.

Dental age estimation in children affected by juvenile rheumatoid arthritis

Abstract

Dental root calcification has proven to be a reliable biological evidence to estimate chronological age of children. The development of structures usually examined in the age estimation forensic practice (e.g. skeleton, teeth) is supposed to be influenced by diseases and nutritional, environmental, ethnic, and ultimately even socioeconomic factors. This research aims to study the age estimation in children affected by juvenile rheumatoid arthritis (JRA) with and without steroids treatment and compared with healthy subjects.

Material and methods

Dental age estimations based on 752 OPGs, 420 girls and 332 boys, aged from 3.3 to 15.99 years, were provided by applying Demirjian and Willems’ original methods. Of the whole sample, 103 individuals were affected by JRA and 40 received a continuous corticosteroid therapy, over 1 year long.

Conclusions

Willems’ and Demirjian’s original methods, as methods commonly applied to estimate age for sub-adults with unremarkable medical history, can be used for medico-legal purposes to children affected by JRA. Willems’ method tended to underestimate age while Demirjian’s method resulted to be prone to overestimation for both healthy and JRA-affected children. JRA showed to have no influence on root calcification process even in children that received steroid treatment for 1 year or longer.

Electronic supplementary material

The online version of this article (10.1007/s00414-020-02395-w) contains supplementary material, which is available to authorized users.

Forensic odontology: The prosthetic ID

The term “forensic science” involves forensic (or forensis, in Latin), which means a public discussion or debate. In a more modern context, however, forensic applies to courts or the judicial system. Combine that with science, and forensic science means applying scientific methods and processes to solving crimes. People can be identified by their fingerprints, foot creases, and from traces of their DNA from blood, skin, hair, saliva, and semen by DNA analysis. However, in situations where these records are unavailable or unusable due to the nature of the disaster, the dental records and aids prove to be useful for victim identification. This article aims at highlighting the importance of the dental records and the forensic odontology in the accurate and efficient identification of the conflict victims or deceased to serve as an important adjunct to the forensic medicine in a simplified manner.

Automatic human identification from panoramic dental radiographs using the convolutional neural network

Human identification is an important task in mass disaster and criminal investigations. Although several automatic dental identification systems have been proposed, accurate and fast identification from panoramic dental radiographs (PDRs) remains a challenging issue. In this study, an automatic human identification system (DENT-net) was developed using the customized convolutional neural network (CNN). The DENT-net was trained on 15,369 PDRs from 6300 individuals. The PDRs were preprocessed by affine transformation and histogram equalization. The DENT-net took 128 × 128 × 7 square patches as input, including the whole PDR and six details extracted from the PDR. Using the DENT-net, the feature extraction took around 10 milliseconds per image and the running time for retrieval was 33.03 milliseconds in a 2000-individual database, promising an application on larger databases. The visualization of CNN showed that the teeth, maxilla, and mandible all contributed to human identification. The DENT-net achieved Rank-1 accuracy of 85.16% and Rank-5 accuracy of 97.74% for human identification. The present results demonstrated that human identification can be achieved from PDRs by CNN with high accuracy and speed. The present system can be used without any special equipment or knowledge to generate the candidate images. While the final decision should be made by human specialists in practice. It is expected to aid human identification in mass disaster and criminal investigation.

Forensic study of mechanical properties of dental fillings after immersion in marine environment

Human identification and postmortem intervals can be difficult to estimate when corpses are found in drowning situations, and forensic odontologists can bring valuable input to forensic science investigations of this type. Studies that simulate real scenarios are crucial for providing parameters that can be used in real cases. The present study created the necessary circumstances, i.e. immersion in a marine environment, to estimate the changes in the mechanical properties (Knoop microhardness, roughness, and color) of various dental fillings (silver amalgam, composite resin, and glass ionomer cement) over different immersion periods of time (one and three months). The silver amalgam fillings showed a significant increase in surface roughness. The composite resin fillings showed statistically significant increases in surface roughness and Knoop microhardness, and the glass ionomer cement showed a significant increase in surface roughness. These results lead to the conclusion that teeth restored with silver amalgam, composite resin, and glass ionomer cement, when subjected to immersion in marine environments, produce different changes in surface roughness, Knoop microhardness, and color properties depending on the length of immersion time. These findings could help in the field of forensic science to accurately estimate immersion time of dead bodies found in marine environments.

A Comparative Evaluation of Three Different Dental Age Estimation Methods in India: A Test of Ethnic Variability

Aim

The present study aimed to evaluate and compare the applicability of Demirjian, Willems, and Haavikko methods of dental age estimation in southeastern (Dravidian ethnicity) and northwestern regions (Aryan ethnicity) of the Indian population.

Materials and methods

The study includes the orthopantomographs (OPGs) of 303 individuals (173 males and 130 females) of age ranging from 5 to 14 years. The participants in the present research were evaluated under two study groups: group I: participants of the southeastern region and group II: participants of the northwestern region. Dental age was calculated using Demirjian, Willems, and Haavikko methods and compared with the chronologic age of each participant. The accuracy of dental age estimation methods was evaluated by mean absolute error. One-way analysis of variance (ANOVA) and Student's t tests were used to test the significant difference between the chronologic age and estimated dental ages.

Results

The Demirjian method showed overestimation, while Willems and Haavikko methods showed underestimation for boys and girls in both the ethnic groups of Indian population. The Willems method of dental age estimation showed comparatively more accurate and reliable results in both the ethnic groups of the Indian population.

Conclusion

The dental age estimation by Demirjian, Willems, and Haavikko methods showed no significant variation between the different ethnicities of the Indian population.

Clinical significance

The present research will be helpful in pedodontic, orthodontic, and forensic investigations for accurate and reliable dental age estimation in different parts of Indian population.

How to cite this article

Chaudhry K, Talwar M, Vanga NRV, et al. A Comparative Evaluation of Three Different Dental Age Estimation Methods in India: A Test of Ethnic Variability. Int J Clin Pediatr Dent 2020;13(1):16–20.

Examination of the radiographic visibility of the root pulp of the mandibular second molars as an age marker

Forensic odontologists often confront with conceptually simple medicolegal question of whether an individual is a juvenile or an adult. The demand for additional research into extending dental age estimation methods in late adolescence is never the less, especially in those who have passed 15 years and are suspected older than 18 years. The present research investigated the regressive dental characteristic, i.e. radiographic visibility of the root pulp in mandibular second molars for the purpose of age assessment, especially for determining the age over 18 years. Nine hundred thirty-six orthopantomograms comprised of 436 males and 500 females aged from 14 to 22 years were examined. Descriptive statistics were performed for each stage in both sexes. The correlation statistics revealed that there is a strong, positive correlation between the chronological age and root pulp visibility stages. The analysis revealed that stage 0 occurred first at the age of 14 years in both sexes. Stage 1 first occurred at the age of 14.26 years in females and 14.74 years in males. Stage 2 was first achieved at the age of 18.6 and 15.2 years in males and females, respectively. The suitability of the studied characteristics in mandibular second molars for age estimation could be confirmed but of limited value. The presence of this stage 2 root pulp visibility in male subjects represents a potential criterion for indicating the age over 18 years. In future studies, the pattern of secondary dentin formation in other tooth types should be investigated.

Profound approach to check legitimacy of an old technique used to gauge palatal rugae

Aims

The present study aimed at assessing two fixed points of reference from where the mesial and distal point of all rugae can be measured so that the exact movement of particular rugae in any direction can be evaluated and assessing the changes in the palatal rugae after orthodontic treatment.

Methods

A longitudinal study conducted among a sample of 20 (8 male and 12 female) adult patients. Pre- and post-orthodontic treatment casts of patients were obtained from the Department of Orthodontics College of Dentistry Jazan University. Antero-posterior linear distances (Technique I) between medial and lateral points of primary, secondary and tertiary rugae were measured. Also, the transverse linear distance (Technique II) between medial and lateral points of right and left rugae were measured. Technique III involved marking two fixed points and using these two points a third point is located on the medial or lateral end of rugae of right and left side in pre and post-treatment orthodontic casts. The independent sample t-test was employed to compare gender. Difference between the pre- and post-treatment mean values were checked by the paired t-test.

Results

Technique III successfully showed the statistically significant difference (P ≤ 0.05, 95% CI) in the overall pre and post-treatment values on the patients' cast (N = 20) which was not observed with a technique I and technique II.

Conclusion

The triangle created by the three reference points in the technique III was able to identify the changes in the palatine rugae more precisely than the technique I and Technique II.

Dental autopsy recommendations in SARS-CoV-2 infected cases

Unidentified human remains with unknown medical history can always pose biological hazards to forensic pathologists and odontologists, including hepatitis C, HIV infection, Middle East respiratory syndrome (MERS), hemorrhagic fever viruses such as Ebola, meningitis and now Sars-Cov2. The pandemic of the new coronavirus disease (COVID-19) has reached 185 Countries with an increasing number of deaths. Forensic pathologists and odontologists may find themselves having to perform an identification autopsy to confirmed or suspected Sars-Cov2 positive deaths. By respecting the entire set of universal precautions and recommendations the highlighted risks can be minimized, and best practice in human identification should always be a priority for human rights of the dead. The following article is a summary of the recommendations for conducting dental autopsies and management of suspected COVID-19 cases.

Odontological identification dental charts based upon postmortem computed tomography compared to dental charts based upon postmortem clinical examinations

Since the beginning of this century, the use of postmortem computed tomography (PMCT) in forensic autopsies has increased. In this study we examined how similar dental charts created using PMCT as a solitary examination mode were to dental charts created using the conventional method of a clinical inspection including intraoral radiographs. A total of 100 previously performed dental identification cases were retrospectively included in the study. For each case, a dental chart was created solely based upon PMCT. The PMCT based dental chart was subsequently compared with the chart created from the previous conventional identification examination. Based upon the accuracy, sensitivity and specificity values PMCT performed very well compared to the conventional method in the identification concerning presence or absence of teeth, the presence of crowns, bridges and endodontic treatments as well as the presence and types of fillings. PMCT performed poorly concerning the extension of fillings and identification of small, tooth-colored fillings. The use of PMCT is a valuable supplement to the conventional methods available for forensic odontologists and may be of great value for initial screening in mass fatalities.

Detection of DNA adduct 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a toxicity bioindicator to the effects of nickel on Ni-Cr alloy prosthesis users

Previous studies have suggested that exposure to Ni from Ni-Cr alloys can affect the human body through oxidative stress. The present study discusses the effect of nickel from Ni-Cr alloy prostheses on the formation of DNA Adduct 8-Hydroxy-2′-Deoxyguanosine (8-OHdG), evaluated based on creatinine and 8-OHdG concentrations in urine, determined with LC-MS/MS, for a Ni-Cr alloy user group and a never-user control group. The mean creatinine and 8-OHdG concentrations were not significantly different between the test groups, although highest levels were observed for the in the Ni-Cr user group. It is suggested that samples with relatively high creatinine and/or 8-OHdG levels are further studied in more detail for stability of concentrations and for the effect of contributing factors.

Age estimation of Brazilian individuals using the London Atlas

OBJECTIVE

The objective of the present study was to evaluate, for the first time, the applicability of the London Atlas method for age estimation on a sample of Brazilian population.

DESIGN

The study consisted of archived dental panoramic radiographs (n = 288) of individuals aged between 5 and 23 years. Radiographs were assessed using the London Atlas method to determine the developmental and eruption stages of all teeth on each sides of each jaw separately, and also to make an age estimation.

RESULTS

There was no significant differences between the right and left sides of the jaws (p = 0.31 for males and p = 0.65 for females). An overestimation of age occurred more likely in the female sample when compared to the male sample. Three age groups, 20.5, 18.5 and 19.5 years, presented the highest values ​​of mean absolute difference found in the whole sample.

CONCLUSION

The London Atlas of age estimation performed well in general and good viability in an expert context, with most age groups showing age differences lower than two years of age, however it is necessary that it be applied with caution in certain age groups, especially when the third molar is used as a decision tooth for age estimation. Therefore, it is recommended to use more than one method for assessing the age in those age groups.

Effect of high temperatures on teeth fixed with an orthodontic bracket. An in vitro study

In cases of incineration, where the identification of victims by conventional methods is impossible, teeth and dental materials become an available source of evidence - thanks to their ability to resist high temperatures. Currently, there is no experimental research to determine the behavior of the bracket and the dental structure when it is attached to the tooth after being exposed to high temperatures. An experimental in vitro study was carried out on 60 upper and lower premolar teeth (30 with a cemented bracket and 30 teeth without a bracket) that were exposed to six temperature ranges (200 °C, 400 °C, 600 °C, 800 °C, 1000 °C and 1200 °C). With the help of an Optiks® binocular stereomicroscope, macroscopic changes were described for each temperature; in addition, the mesio-distal diameter of the crown of the teeth and the bracket were measured before and after the incineration. A comparison of the diameters between the groups [the experimental group and the control group] and between the different temperatures was made. Both teeth, with brackets and without brackets showed macroscopic changes, such as fissures, cracks, fragmentation, enamel bursting and enamel and dentin separation according to the temperature range exposed. The detachment of the bracket was presented at 600 °C - leaving a mark on the dental surface. At above 1000 °C, the crown of the tooth with bracket acquired a pink color and the surface of the bracket became rough and opaque. At above 400 °C, both groups experienced an expansion in the crown dimension without significant differences. The results of this research suggest that teeth with attached brackets are equally resistant as the teeth without brackets, and that the adhesion of these attachments to the dental structure leave characteristics that allow them to be differentiated from teeth without braces -as well as suggesting the orientation to the temperature exposure.

Prediction Formula of Permanent Canine and Premolar Eruption in Mixed Dentition Patients at Universitas Airlangga, Dental Hospital Surabaya, Indonesia

Background

The eruption of permanent canine, first and second premolars need to be predicted because they are erupted last, before the eruption of permanent first and second molars, in order to estimate the available space in orthodontic treatment.

Aim

This study aimed to predict the eruption of permanent canine, first and second premolars in mixed dentition.

Materials and Methods

A cross sectional clinical observation was conducted in 21 subjects of 13 males nad 8 females with the age range of 8-12 years old. Their panoramic radiographs were used to create a prediction formula of permanent canine and premolars. The independent variables of this research are age, weight, height, birth weight, birth height, period of breastfeeding, and vertical distance of eruption. Data were analyzed by coefficient of multiple correlation followed by multiple linear regression analysis.

Results

The prediction formula is as follows: Y = -5107 + 1645 X ₁ + 078 X ₂, where Y is the time of eruption, X ₁ is the height, and X ₂ is the vertical distance of eruption.

Conclusion

The prediction formula is useful for serial extraction in orthodontic treatment. It is also useful for forensic odontology, especially in the determination or identification of ages. It is recommended to be implemented in the science of development, especially in orthodontics and forensic odontology.

Forensic study of mechanical properties of dental restoration after burial in mangrove environment

Conducting research in the field of forensic sciences with methodologies that simulate situations found in the day-to-day practice of a given field of expertise is relevant insofar as this approach can produce results that are as close as possible to reality. In this context, the present study provided situations based on burial in a mangrove environment to estimate the changes in the mechanical properties (Knoop microhardness, roughness and color) of dental restorations utilizing silver amalgam, composite resin and glass ionomer cement over the time of burial. The silver amalgam showed a significant increase in surface roughness and a reduction in Knoop microhardness. Composite resin showed a statistically significant increase in color variation, and the glass ionomer cement showed significant increases in color variation and Knoop microhardness. These results allowed us to conclude that teeth restored with silver amalgam, composite resin and glass ionomer cement submitted to burial in mangrove environments produce different changes in surface roughness, Knoop microhardness and color properties depending on the time of burial to which the victims were submitted. These proprieties could help the forensic sciences to estimate time intervals for burial in mangrove environments.

Preliminary analysis testing the accuracy of radiographic visibility of root pulp in the mandibular first molars as a maturity marker at age threshold of 18 years

Forensic age estimation, after completion of third molar mineralization, regressive features such as apposition of secondary dentin, which is seen as narrowing of the pulp space in the radiographs, can be used as an alternative. In the present study, we explored the radiographic visibility of the root pulp of mandibular first molars using stage classification of Olze et al. (Int J Legal Med 124(3):183-186, 2010) in a sample of 901 orthopantomograms (404 males and 497 females) of south Indian origin with age ranging from 14 to 22 years. Descriptive statistics for the stages according to age was performed for both sexes separately. The strength and direction of the relationship between the chronological age and pulp visualization stages was tested using spearman's rho correlation statistics. The relationship between age and stage attainment showed statistical significance for both sexes. A strong, positive correlation was seen between the stage and chronological age. All males and females presenting stage 0 of root pulp visibility were younger than 18 years. If stage 1 is determined, it is highly possible that an individual regardless of sex is younger than 18 years. Stage 2 was attained in 79.6% males and 83.1% females who were at least 18 years. One hundred percent males and 92.8% females with stage 3 were at least 18 years. The accuracy of this method in mandibular first molars for estimating age threshold of 18 years ranged from moderate to high. However, it is recommended to use this method in conjunction with other age estimation methods.

Transition analysis applied to third molar development in a Danish population

INTRODUCTION

Age assessment based on dental development is often requested in order to assess whether an individual is older or younger than 18 years of age. There are several statistical approaches to estimate age based upon third molar development. The aim of this study was to apply the principles of transition analysis (TA) to a Danish reference material and to evaluate whether it was indicated to include a model that allows for logistic non-linearity as opposed to applying a model only allowing for logistic linearity. For this we chose to use the generalized additive model (gam) and the generalized linear model (glm), respectively.

MATERIAL AND METHOD

A cross-sectional sample comprising 1302 panoramic radiographs of Danish subjects in the chronological age range of 13-25 years was included. All present third molars had been scored according to the 10-stage method of Gleiser and Hunt. Each transition from one stage to the subsequent stage was analyzed according to the statistical approach of TA and fitted with both the generalized linear model (glm) and the generalized additive model (gam). In order to assess whether gam or glm was more parsimonious for each transition individually, the Akaikon information criterion (AIC) was applied.

RESULTS

The results emphasized the importance of applying a statistical model that sufficiently captures the spread of the age estimate. The AIC values showed that some transitions were sufficiently described by glm whereas for others the gam curves fitted significantly better.

CONCLUSION

We recommend that for an age assessment tool based on TA, both a fitting allowing for non-linearity and one allowing only for linearity should be included.

Social contribution of forensic odontology in Japan

Half a century has passed since the department for education and research on forensic odontology was established at dentistry-related universities in Japan in 1964. In order to meet the demands of society, the number of universities with a department of forensic odontology increased up until around 2005. In 2007, the Japanese Society of Forensic Dental Science was established, and then a series of reforms such as establishment of the Study Council on Death Cause Investigation in both the National Police Agency and the Cabinet Office of the Japanese government, cabinet decision of enactment and enforcement of new laws on death cause investigation, publication of an article on the Model Core Curriculum of Dental Education, publication of the results of a fact-finding survey on education and research on forensic odontology conducted by the Ministry of Education, Culture, Sports, Science and Technology, inclusion of questions about forensic odontology in the National Board Dental Examination, and compilation of a database on dental findings by the Ministry of Health, Labor and Welfare, proceeded in succession. We introduced the half century of forensic odontology in Japan in chronological order.

Accuracy of the lower third molar radiographic imaging to estimate age among Ugandan young people

OBJECTIVE

Dental development is a useful method for age estimation. Although third molar eruption is commonly used to estimate age in Uganda, it is reported to be unreliable because of external influences. The more reliable radiographic techniques have inter-ethnic differences but data from sub-Saharan Africa are limited regarding estimating age in young adults. This study, therefore, aimed at determining the accuracy of Demirjian's classification of the lower third molar, a common dental age estimation method, in estimating key ages in a Ugandan population using Ugandan references. Dental records of 1021 Ugandans aged 10-22 years were assigned to two groups; reference and test. The reference data was retrieved from a database of a previous bigger research project.

RESULTS

The overall sample population comprised of 514/1021 (50.3%) males. The mean age was 15.8 (3.6) years. No significant sex differences in dental age were established in the reference sample (520 records). Accuracy values (area under the curve) at the 12-, 14-, 16- and 18-year cut-offs were between 0.83 and 0.90 using the test sample (501 records). The results suggest that Demirjian's classification of the lower third molars is a useful method for age estimation in the young urban Ugandan population in the 10-22-year age-group.