Optimization of forensic identification through 3-dimensional imaging analysis of labial tooth surface using open-source software

Purpose

The objective of this study was to determine the minimum number of teeth in the anterior dental arch that would yield accurate results for individual identification in forensic contexts.

Materials and Methods

The study involved the analysis of 28 sets of 3-dimensional (3D) point cloud data, focused on the labial surface of the anterior teeth. These datasets were superimposed within each group in both genuine and imposter pairs. Group A incorporated data from the right to the left central incisor, group B from the right to the left lateral incisor, and group C from the right to the left canine. A comprehensive analysis was conducted, including the evaluation of root mean square error (RMSE) values and the distances resulting from the superimposition of dental arch segments. All analyses were conducted using CloudCompare version 2.12.4 (Telecom ParisTech and R&D, Kyiv, Ukraine).

Results

The distances between genuine pairs in groups A, B, and C displayed an average range of 0.153 to 0.184 mm. In contrast, distances for imposter pairs ranged from 0.338 to 0.522 mm. RMSE values for genuine pairs showed an average range of 0.166 to 0.177, whereas those for imposter pairs ranged from 0.424 to 0.638. A statistically significant difference was observed between the distances of genuine and imposter pairs (P<0.05).

Conclusion

The exceptional performance observed for the labial surfaces of anterior teeth underscores their potential as a dependable criterion for accurate 3D dental identification. This was achieved by assessing a minimum of 4 teeth.

Dental age estimation in Indonesian adults: An investigation of the maxillary canine pulp-to-tooth volume ratio using cone-beam computed tomography

Purpose

This study was performed to develop a linear regression model using the pulp-to-tooth volume ratio (PTVR) ratio of the maxillary canine, assessed through cone-beam computed tomography (CBCT) images, to predict chronological age (CA) in Indonesian adults.

Materials and Methods

A sample of 99 maxillary canines was collected from patients between 20 and 49.99 years old. These samples were obtained from CBCT scans taken at the Universitas Padjadjaran Dental Hospital in Indonesia between 2018 and 2022. Pulp volume (PV) and tooth volume (TV) were measured using ITK-SNAP, while PTVR was calculated from the PV/TV ratio. Using RStudio, a linear regression was performed to predict CA using PTVR. Additionally, correlation and observer agreement were assessed.

Results

The PTVR method demonstrated excellent reproducibility, and a significant correlation was found between the PTVR of the maxillary canine and CA (r=-0.74, P<0.01). The linear regression analysis showed an R2 of 0.58, a root mean square error of 5.85, and a mean absolute error of 4.31.

Conclusion

Linear regression using the PTVR can be effectively applied to predict CA in Indonesian adults between 20 and 49.99 years of age. As models of this type can be population-specific, recalibration for each population is encouraged. Additionally, future research should explore the use of other teeth, such as molars.

Age Estimation Using the Tooth Coronal Index on Mandibular First Premolars on Digital Panoramic Radiographs in an Indian Population

Objectives: Age estimation is a crucial aspect of forensic odontology, and the Tooth Coronal Index (TCI) has been widely used for forensic purposes in determining age. The aim of this research was to evaluate the effectiveness of TCI in age estimation. Materials and Methods: A retrospective study was conducted, and TCI was calculated for the mandibular first premolar in 700 digital panoramic radiographs. Age was divided into five groups: 20-30 years, 31-40 years, 41-50 years, 51-60 years, and >61 years. Bivariate correlation was used to establish the relationship between TCI and age. Linear regression was calculated for the different age groups and genders. Inter-observer reliability and agreement were assessed using one-way ANOVA. P-values less than 0.05 were considered statistically significant. Results: Comparison of the mean difference from actual age showed underestimation in males aged 20-30 years and overestimation in males over 60 years of age. The least difference between actual and calculated age was found in females aged 31-40 years. Inter-age comparison using ANOVA for females demonstrated a statistically highly significant difference from actual age in all age groups (P<0.01), with the highest mean in females aged 51-60 years and the lowest in females aged 31-40 years. Inter-group comparison of mean TCI revealed statistically non-significant differences in males and statistically highly significant differences in females (P<0.01). Conclusion: Age estimation using TCI on mandibular first premolars can be recommended as an easy, non-invasive, and less time-consuming method. This study suggests that regression formulas were more accurate for males aged 31-40 years.

Quantitative and Qualitative Approaches for Dental Age Assessment in Sub Adult Portuguese Population: European Regression Formula and Demirjian Stages

INTRODUCTION

Over the last decade, the criminal justice system among the European countries deals with a new group of people, the undocumented people. In the criminal field, most of the suspected claimed to be under the minor legal age according to the type of crime. The government of each European country is committed to protecting the children and vulnerable people. There are serious safety concerns since adults falsely claim to be minors and legal systems oppose to such claims. In this study, we have used different age assessment methods and some of them without accuracy.

OBJECTIVE

To meet the general considerations we developed a study using the current dental age assessment methods. Hence, for the Portuguese population, this study aims to validate the European regression formula between the ages of 6 and 15 years of age; to estimate the cut-off point for the age of 12 years, and to compare the quantitative approach of European regression formula with Demirjian's qualitative approach for age estimation.

MATERIAL AND METHODS

483 orthopantomograms were analysed using the European formula and Demirjian scoring stages. A new method, Model 2, was designed to better suit the Portuguese population.

RESULTS

The European formula: average age underestimation of 4.88 for the third quadrant and 4.04 months for the fourth quadrant; and a mean absolute error (MAE) of 10.93 and 10.68 months respectively. Demirjian method: average overestimation of 8.70 months, MAE of 12.85 months. In Model 2: MAE of 9.37 months for the third quadrant, and 9.28 months for the fourth quadrant. Both European formula and Demirjian method had an area under ROC curves results above 0.93. Discrepancy of sensitivity between methods for the specific cut-off point: 11.48. The results obtained in this study can be extrapolated to 87.33% of the Portuguese population.

CONCLUSIONS

The European regression formula can be applied for the Portuguese population, and seems to be more accurate than Demirjian's methodology in this population. Nevertheless, both European regression formula and Demirjian method present similarly suitable results in the classification of 12 years of age, although there is a noticeable discrepancy favouring the European regression formula. The European Formula when applied for criminal age assessment, independently of population, is mandatory to indicate to the judicial institutions, the sensitivity of the results.

Diagnostic accuracy of the third molar maturity index (I3M) to assess the age of legal majority in Northern Brazil-population-specific cut-off values

International guidelines for dental age assessment have recommended the use of methods based on available population-specific data. The Third Molar Maturity Index (I_3M) was previously validated in several populations worldwide. This was the first study to evaluate the I_3M in a northern Brazilian population and to test the diagnostic accuracy of the method to distinguish between minors and adults. The sample consisted of 1.070 panoramic radiographs retrospectively collected from females (n = 595) and males (n = 475) with ages between 16 and 22 years. I_3M's original cut-off value of 0.08 was used to classify individuals below and above the age of 18. Receiver operating characteristic (ROC) curves were plotted to assess the accuracy (ACC) of the method. In females and males separately, the overall ACC was 73.1% and 80%, respectively. The overall ACC for the combined sample was 76.1%. For northern Brazilian males, the best cut-off value remained 0.08, while for females, an adjustment to 0.12 showed optimal outcomes. The new cut-off value led to an ACC of 98.5% for females, which reflected an increase of 25.5% compared to the original cut-off value. The original cut-off value proposed by I_3M was applicable to the present sample of northern Brazilian individuals. Adjustments to 0.12, however, may be encouraged to enhance the performance of the method among females.

Testing the Olze and Timme Methods for Dental Age Estimation in Radiographs of Brazilian Subadults and Adults

Aim

This study aimed to test the applicability of the methods proposed by Olze et al. (2012) and Timme et al. for dental age estimation in Brazilian subadults and adults.

Material and methods

Panoramic radiographs of 503 individuals aged between 20 and 70 years were analyzed. The mean chronological age of males and females of the sample was 29.04 and 29.97 years, receptively. Secondary dentin formation, cementum apposition, periodontal recession, and attrition of teeth #34, #35, #44 and #45 teeth were assessed as parameters to be calculated in the formulae designed by Olze et al. and Timme et al.

Results

In males, the mean estimated age by the Olze method was 28.97 ± 2.86 years, while in females it was 27.85 ± 2.70 years. The Timme method estimated mean age for males of 32.54 ± 5.32 years and for females 33.09 ± 5.16 years. Low coefficients of determination (r²) for the application of tooth-specific formulae of both methods suggest that estimated and chronological ages were not properly associated.

Conclusion

The outcomes of this study indicate that the Olze and Timme methods may be limited for forensic applications in Brazilian subadults and adults. Country-specific statistical adjustments might be useful for improvements in practice.

Age estimation in humans through the analysis of aspartic acid racemization from teeth: A scoping review of methods, outcomes, and open research questions

Teeth are considered the most resistant structures in the human body. In forensic odontology, teeth are useful for human identification, especially when dental age estimation is necessary. Despite numerous studies, there is no consensus regarding the best methods for dental age estimation. The analysis of aspartic acid racemization, however, has shown promising results. This scoping review aimed to present a descriptive synthesis of the current literature regarding dental age estimation through aspartic acid racemization. Four electronic databases were screened: PubMed, Scielo, Web of Science, and Scopus. Cross-sectional studies published before April 2021 were selected. From 206 articles found, 26 met the eligibility criteria. Several experimental protocols and laboratory settings were detected, but the different protocols did not seem to significantly reduce error rates in dental age estimation. The analysis of aspartic acid racemization in human dental tissues produced accurate and potentially reliable results for age estimation. Aspartic acid racemization stands out especially in the adulthood - age category in which other methods struggle to deliver proper performances. Studies with larger samples, independent testing, and standardized laboratory procedures are necessary. Equator-like reporting guidelines are encouraged to enable future systematic reviews and meta-analyses.

A literature review on dental autopsy - an invaluable investigative technique in forensics

Forensic odontology is a specialty of dental sciences that deals with dental evidence in the interest of the justice system. The science of autopsy has been developing from the ancient times even before the popularization of general medicine. The objective of a medico-legal autopsy is to identify significant clues for an ongoing forensic investigation. However, in certain circumstances, it is difficult to conduct an oral examination owing to the anatomic location of the oral cavity. The onset of rigor mortis after death poses further complications. Thus, skillful and sequential dissections of the oral and para-oral structures are required to expose the dentition. Dental autopsy includes incisions and resection of the jaw for the detailed examination of the oral cavity. The procedure involves various modes of examination, including visual and radiographic, which help in human identification in forensic investigation. The present paper provides an overview of the various methods of dental autopsy.

A pilot study of an automated personal identification process: Applying machine learning to panoramic radiographs

Purpose

This study aimed to assess the usefulness of machine learning and automation techniques to match pairs of panoramic radiographs for personal identification.

Materials and Methods

Two hundred panoramic radiographs from 100 patients (50 males and 50 females) were randomly selected from a private radiological service database. Initially, 14 linear and angular measurements of the radiographs were made by an expert. Eight ratio indices derived from the original measurements were applied to a statistical algorithm to match radiographs from the same patients, simulating a semi-automated personal identification process. Subsequently, measurements were automatically generated using a deep neural network for image recognition, simulating a fully automated personal identification process.

Results

Approximately 85% of the radiographs were correctly matched by the automated personal identification process. In a limited number of cases, the image recognition algorithm identified 2 potential matches for the same individual. No statistically significant differences were found between measurements performed by the expert on panoramic radiographs from the same patients.

Conclusion

Personal identification might be performed with the aid of image recognition algorithms and machine learning techniques. This approach will likely facilitate the complex task of personal identification by performing an initial screening of radiographs and matching ante-mortem and post-mortem images from the same individuals.

Computerized delineation of the teeth and comparison with a smiling photograph: identification of a body skeletonized by cadaverous ichthyofauna action

Amazonian's forensic experts usually experience considerable difficulties in the identification of drowned bodies rescued from the rivers of the Amazon basin, since they are frequently found skeletonized by the action of the cadaverous ichthyofauna. In these circumstances, especially when the soft tissues are completely absent, bones and teeth may represent the unique source of information for the identification of the body. This work reports a case of positive identification of a body skeletonized by scavenger ichthyofauna. The identification was performed by comparing computerized delineation of the dental characteristics of the cadaver with those observed in a smiling photograph of the victim. This report also highlights the ferocity of Cetopsis candiru (candiru cobra), Cetopsis coecutiens (candiru-açu) and Calophysus macropterus (piracatinga).

Dental Age Assessment by I2M and I3M: Portuguese Legal Age Thresholds of 12 and 14 Year Olds

Objective

Better understanding of dental age assessment may help in cases of age estimation in Forensic Clinics. The first aim was to provide essential information on method reliability for upcoming studies using dental age assessment by second molar index (I_2M), and third molar index (I_3M) for age estimation on legal ages of 12 - 14 years. The second aim was to document forensic method outcomes of the Demirjian method which has already been used in forensic clinic.

Material and Methods

Two samples were used for this purpose: for I_2M, 633 orthopantomographs (270 females / 363 males), the age range from 7 to 17 years and for I_3M, 471 orthopantomographs (253 females / 218 males), the age range from 10 to 23 years, from the database population of Lisbon North University Hospital Center, approved by the Ethic Committee.

Results

The I_3M cut-off point (1.133) for 12- year- olds obtained better results than the cut-off point stated by the I_2M (0.135). Besides, I_2M cut-off point (0.001) for 14- year- olds showed better results when compared with the cut-off point (0.705) established by the I_3M. Both methods are reliable for the legal age thresholds of 12 and 14 years. However, using I_2M and I_3M allows us to vary the cut-off value to privilege sensitivities or specificity, depending on which is more appropriate to the intended application.

Conclusions

The accuracy (88.94%) of I_3M obtained better results for the 12- year- old cut-off point (1.133) and the accuracy (90.21%) of the I_2M performed better for the 14- year- old cut-off point (0.001).

[Skull-facial anthropometric traits of forensic odontological interest for estimating sex, race and age. Review of the literature]

One of the main functions of anthropologists and forensic dentists is to identify subjects according to physical characteristics of the features presented using non-routine methods. These characteristics, especially bone, allow professional to determine the sex, age and racial origin of the remains or skeleton found. Dentist focus on features belonging to the stomatognathic system, while anthropologists study the bones that make up the human body. In this study, we describe the investigations of cranio-facial anthropometric features of dental interest carried out by anthropologists to identify the sex, race and age of skeletal remains or skeletons. in addition, we describe the so-called dental anthropology that studies the elements of the stomatognathic system from an anthropological point of view. Electronic literature was reviewed through search engines such as PUBMED, Google Academic and SciELO with the search terms "Forensic Dentistry, Forensic Anthropology, Sex Determination, Ancestry Determination and Age Determination". Knowledge of the craniofacial anthropological features from the forensic point of view is of great importance in individualized and multidisciplinary studies by forensic dentists and anthropologists in the identification of skeletal remains.

Transfer Learning Based Automatic Human Identification using Dental Traits- An Aid to Forensic Odontology

Forensic Odontology deals with identifying humans based on their dental traits because of their robust nature. Classical methods of human identification require more manual effort and are difficult to use for large number of Images. A Novel way of automating the process of human identification by using deep learning approaches is proposed in this paper. Transfer learning using AlexNet is applied in three stages: In the first stage, the features of the query tooth image are extracted and its location is identified as either in the upper or lower Jaw. In the second stage of transfer learning, the tooth is then classified into any of the four classes namely Molar, Premolar, Canine or Incisor. In the last stage, the classified tooth is then numbered according to the universal numbering system and finally the candidate identification is made by using distance as metrics. These three stage transfer learning approach proposed in this work helps in reducing the search space in the process of candidate matching. Also, instead of making the network classify all the 32 teeth into 32 different classes, this approach reduces the number of classes assigned to the classification layer in each stage thereby increasing the performance of the network. This work outperforms the classical approaches in terms of both accuracy and precision. The hit rate in human identification is also higher compared to the other state-of-art methods.

Mandibular Measurements for Sex and Age Estimation in Brazilian Sampling

Objective

The present study aimed to evaluate the possibility of sex and age estimation in a Brazilian sample, using the following five mandibular measurements: coronoid height, gonial angle, bigonial distance, ramus height, maximum length.

Materials and methods

In total, 103 mandibles were measured, 53 female and 50 male, grouped according to the age in 5 different groups. Two different observers performed all these measurements. For statistical analysis, one-way ANOVA was used with a significance level of 5% to verify if the mandibular measurements were related to age. The Student t-test was used for comparisons between the sex samples. Eighty three samples were used to develop a logistic regression model. The intra-observer and inter-observer differences were evaluated using the Kappa coefficient.

Results

The sex differences were statistically significant in all the variables, and all of them were larger in men, apart from the variable related to the gonial angle (GA), which was larger in women. For the logistic regression formula, the variables used were: bigonial distance and mandibular ramus, with 90% accuracy. For age, the measurements did not show a pattern. The inter and intra-observer values were greater than 0.85.

Conclusion

In conclusion, it is possible to estimate sex using mandibular measurements, but it is not recommended to use these measurements for age estimation.

Dental Age Estimation based on Development Dental Atlas Assessment in a Child/Adolescent Population with Systemic Diseases

Background

Forensic estimation of chronological age has played an increasingly important role as part of cadaver identification, and also in living individuals due to the phenomenon of immigration and sexual abuse of undocumented trafficked children.

Objective

This research aimed to validate the already used dental mineralization and eruption atlas in normal children and adolescent population in estimating chronological age in a young population, particularly those with special needs, majority of them with systemic diseases.

Participants and Setting

A sample of 163 orthopantomograms from two independent medical institutions was collected from 133 patients aged between 4 and 23 years.

Method

The orthopantomograms were divided into two groups, 95 from patients with systemic pathologies that have repercussions on dental development and 68 with systemic pathologies without dental repercussions. Dental ages were estimated by the London Atlas using the left side and then independently the right side of the maxilla. The intraobserver and interobserver agreements were evaluated. The difference between dental age estimates and the chronological age and its absolute value were calculated and analyzed.

Results

Statistically significant differences were found between estimates and chronological age, revealing a general prevalence for underestimation; except for those under the age of 12. Nevertheless, the underestimation in individuals under the age of 16 was not significant (with an average of less than one month), while the underestimation was significant for persons who were at least 16 years old (with an average over 26 months). Furthermore, for those persons with systemic diseases with dental repercussions a greater error in underestimation was obtained, which indicates that the midpoint values should be reassessed in persons with Down's syndrome, chromosomal alterations, syndromes and central nervous system disorders.

Conclusions

This atlas can be potentially used as a tool for age estimation in a population with special needs and, also, in a population with systemic diseases, but we suggest further studies with larger international samples to create adequate atlases for all the required scenarios, mainly, diagrams for people with systemic diseases who are over the age of 16.

Dental age estimation using the pulp-to-tooth ratio in canines by neural networks

Purpose

It has been proposed that using new prediction methods, such as neural networks based on dental data, could improve age estimation. This study aimed to assess the possibility of exploiting neural networks for estimating age by means of the pulp-to-tooth ratio in canines as a non-destructive, non-expensive, and accurate method. In addition, the predictive performance of neural networks was compared with that of a linear regression model.

Materials and Methods

Three hundred subjects whose age ranged from 14 to 60 years and were well distributed among various age groups were included in the study. Two statistical software programs, SPSS 21 (IBM Corp., Armonk, NY, USA) and R, were used for statistical analyses.

Results

The results indicated that the neural network model generally performed better than the regression model for estimation of age with pulp-to-tooth ratio data. The prediction errors of the developed neural network model were acceptable, with a root mean square error (RMSE) of 4.40 years and a mean absolute error (MAE) of 4.12 years for the unseen dataset. The prediction errors of the regression model were higher than those of the neural network, with an RMSE of 10.26 years and a MAE of 8.17 years for the test dataset.

Conclusion

The neural network method showed relatively acceptable performance, with an MAE of 4.12 years. The application of neural networks creates new opportunities to obtain more accurate estimations of age in forensic research.

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.

Forensic Medicine and the Military Population: International Dental Records and Personal Identification Concerns

INTRODUCTION

The first goal of this research was to perceive the global commitment towards the organization and archiving of dental records and to compare it with each country's security risk rating. The second one was to study dental records in a sample of the Portuguese military population, using the available national dental records.

MATERIAL AND METHODS

An e-mail was sent to representative dentistry associations in several countries, requesting some information concerning the professionals' awareness of this issue. After obtaining permission from the Ethics Committee, the information was collected through the Forensic Dental Symbols® system into the Dental Encoder®, as an extension of a Spanish study, and a generic codification was used (unrestored, restored, missing and crowned teeth).

RESULTS

The most common dental record retention period is ten years after treatment. Observing the samples' dental records (595 files), we found a total of 19 040 analyzed teeth, with the following frequencies: unrestored (89.6%), restored (7.0%), missing (2.2%) and crowned (1.1%).

DISCUSSION

There is a wide range of guidelines on how long dentists should keep dental records. Especially for the military population, dental records must include detailed information concerning each tooth situation, in order to support the process of human identification.

CONCLUSION

This article reinforces the need for mandatory quality dental records in all countries, which must be efficiently stored and easily accessible in case dental identification is necessary. For the military population, these requirements are especially important, due to the added risks to which this group is subject.

Lip prints- A study of its uniqueness among students of MediCiti Medical College

BACKGROUND

"Cheiloscopy" is a technique that deals with lip prints. The pattern of fine creases on the lips are unique to the individual. They are similar to finger prints and useful in crime investigation.

AIMS AND OBJECTIVES

To study the uniqueness, prevalence, and gender significance of lip print patterns in human subjects.

MATERIALS AND METHODS

The study was conducted on 100 randomly selected male and female undergraduate medical students. The lip print of each subject was obtained and its pattern was analyzed according to Suzuki and Tsuchihashi classification.

RESULTS

The study showed that Type I lip pattern was the commonest.

CONCLUSION

Our study has added to confirmation of the distinctiveness of cheiloscopy, which can be used as an additional tool for identification. Studies on lip prints being very scanty, our findings add significantly to the meager literature on this subject. Further in-depth studies to establish prevalence of patterns in lip prints will certainly help as useful evidence in forensic investigations.

Sex Determination of Adult Human Maxillary Sinuses on Panoramic Radiographs

The purpose of this study was to evaluate dimensions of adult human maxillary sinuses on panoramic radiographs and their possible application on the sex determination for forensic purposes. The sample comprised 64 database panoramic radiographs from individuals aged 20 years or older (32 male and 32 female subjects), with complete permanent dentition (or absence of third molars). One examiner measured the width and height of the right and left maxillary sinuses using the software Image J 1.47v (National Institutes of Health, Bethesda, USA). Measurements were repeated to calculate intra-observer agreement. Chi-Square test, Kappa, ANOVA and T-Student were used for results analysis for p≤ 0.05. Intra-observer agreement with correlation Kappa ranged between 0.38 and 0.96. For female subjects, the mean height and width of the left maxillary sinus were 28.7856mm and 44.6178mm, respectively. And right maxillary sinus was 27.7163mm for height and 45.1850mm for width. Male subjects were found to have the mean height and width of the left maxillary sinus 30.9981mm and 48.7753mm, respectively. And right maxillary sinus was 30.7403mm for height and 48.5753mm for width. There was a statistically significant difference in the height and width of maxillary sinuses between males and females. It can be concluded that maxillary sinuses height and width on panoramic radiographs can be used to determine the gender of adult human subjects.

Accuracy of an equation for estimating age from mandibular third molar development in a Thai population

Purpose

This study assessed the accuracy of age estimates produced by a regression equation derived from lower third molar development in a Thai population.

Materials and Methods

The first part of this study relied on measurements taken from panoramic radiographs of 614 Thai patients aged from 9 to 20. The stage of lower left and right third molar development was observed in each radiograph and a modified Gat score was assigned. Linear regression on this data produced the following equation: Y=9.309+1.673 mG+0.303S (Y=age; mG=modified Gat score; S=sex). In the second part of this study, the predictive accuracy of this equation was evaluated using data from a second set of panoramic radiographs (539 Thai subjects, 9 to 24 years old). Each subject's age was estimated using the above equation and compared against age calculated from a provided date of birth. Estimated and known age data were analyzed using the Pearson correlation coefficient and descriptive statistics.

Results

Ages estimated from lower left and lower right third molar development stage were significantly correlated with the known ages (r=0.818, 0.808, respectively, P≤0.01). 50% of age estimates in the second part of the study fell within a range of error of ±1 year, while 75% fell within a range of error of ±2 years. The study found that the equation tends to estimate age accurately when individuals are 9 to 20 years of age.

Conclusion

The equation can be used for age estimation for Thai populations when the individuals are 9 to 20 years of age.

FORENSIC SCIENCE:: 20 YEARS OF FORENSIC DENTISTRY AT THE UNIVERSITY OF ZAGREB, 1994 - 2014

Data from available literature point to an early beginning of Forensic Dentistry in Croatia relating to a post-mortem examination of a female patient after a dental procedure in the 1930s. Later on, there were several mass casualties due to collisions and airplane crashes and a railway accident at the Zagreb Main Railway Station wherein the identity of the victims was established based on dental features. Foreign experts in forensics helped identify those victims, particularly forensic dentists because this specialty was almost unknown in our region at the time. During the twenty-year period of the development of Forensic Dentistry at the University of Zagreb, the School of Dental Medicine, the city of Zagreb and Croatia have become internationally recognised on the forensic map of the world.

Dental maturity of Saudi children: Role of ethnicity in age determination

Purpose

Demirjian's dental maturity scores and curves have been widely used for human age determination. Several authors have reported considerable differences between the true and estimated age based on the Demirjian curves, which have been accounted for by ethnicity. The purpose of the current study was to assess the role of ethnicity-specific dental maturation curves in age estimation of Saudi children.

Materials and Methods

A sample of 452 healthy Saudi children aged 4 to 14 years were aged based on the original French-Canadian Demirjian curves and several modified Demirjian curves specified for certain ethnic groups: Saudi, Kuwaiti, Polish, Dutch, Pakistani, and Belgian. One-way ANOVA and a post hoc Scheffé's test were used to assess the differences between chronological age and dental age estimated by the different curves (P<0.05).

Results

The curves designed for Dutch, Polish, Saudi, and Belgian (5th percentile) populations had a significantly lower error in estimating age than the original French-Canadian and Belgian (50th percentile) curves. The optimal curve for males was the Saudi one, with a mean absolute difference between estimated age and chronological age of 8.6 months. For females, the optimal curve was the Polish one, with a mean absolute difference of 7.4 months. It was revealed that accurate age determination was not related to certain ethnicity-specific curves.

Conclusion

We conclude that ethnicity might play a role in age determination, but not a principal one.

Time of guard of orthodontic records versus legal time for their prescription

INTRODUCTION

After promulgation and wider dissemination of the Code of Consumer Protection (CCP), there was an increase in the number of legal conflicts between patients and dentists, leading these health professionals to increasingly guard themselves from possible lawsuits. As such, it becomes critical the preparation of an adequate and complete clinical record, even though the keeping time remains uncertain.

OBJECTIVE

To review the literature and discuss the keeping time of orthodontic records versus the legal time for their prescription, as well as to propose a model of a Term upon Completion of Dental Treatment.

CONCLUSIONS

It is advised to return part of the clinical records to their rightful owners by means of an itemized receipt. The Term upon Completion reflects the patient's awareness and could be considered by the CCP as the initial term of the prescription time, because it implicates that the patient recognizes the quality of service provided and satisfactory results achieved.

Uniqueness of radiographic patterns of the frontal sinus for personal identification

Purpose

This study was performed to evaluate the uniqueness and reliability of the frontal sinuses by comparing various patterns of frontal sinus as observed on Waters' radiographs for individual identification.

Materials and Methods

Three Waters' radiographs of 100 individuals, taken on day one, after 6-8 months, and one radiograph with a slight variation in angulation, to mimic conditions out in the field or during autopsy. Three observers were randomly given radiographs from all there packets for comparisons and identification, by the method of superimposition and individual uniqueness.

Results

The comparative identification by superimposition of the frontal sinus was 100% positive. The size, shape, unilateral or bilateral presence, absence, and septa were observed to be unique in each case; neither had the measurements changed over a period of time.

Conclusion

The need to establish a reliable, low-cost, and easily reproducible method for human identification prompted the elaboration of technical, precise, and accessible parameters, such as the evaluation of the area, asymmetry, and shape of the frontal sinus. Comparison among each of the frontal sinuses of the 100 people in the sample revealed that no two sinuses are the same, that is, the sinus is unique to each individual.