Effect of Heat on the Fluorescence Properties of Tooth‐Colored Restorative Materials and Their Forensic Implications

During antemortem and postmortem comparison of dental records of carbonized victims, restorations may be part of such records. The objective of this study was to evaluate the effect of heat on the fluorescence behavior of contemporary tooth‐colored restorative materials and natural tooth structure when subjected to range of temperatures, using illumination with 405 nm wavelength light. A total of 132 human extracted teeth restored with tooth‐colored restorative materials were exposed to heat (200, 500, 900, 1200°C) in an oven for 30 min. Samples were imaged before and after heat treatment. All tooth‐colored restorative materials underwent changes in color and in fluorescence properties, at each of the temperatures used. Resin‐based restorative materials still fluoresced at 200°C, and at 500°C underwent major color changes due to volatilization of resin. Materials containing inorganic fluorophores still fluoresced at 900°C, while at 1200°C, none of the materials tested in this study showed any fluorescence.     

Subarachnoid Hemorrhage and Carbon Monoxide Exposure: Accidental Association or Fatal Link?

This case study reports a fatal subarachnoid hemorrhage (SAH) with concomitant accidental carbon monoxide (CO) exposure in 32‐year‐old man. Autopsy results indicated an antemortem aspiration of smoke, and a massive SAH was identified as the cause of death. Intriguingly, the carboxyhemoglobin level was 30%, suggesting that CO could have played a specific role. Intracranial hemorrhages following CO exposure in brain areas and tissues such as the basal ganglia, globus pallidus, or white matter are rare, but well characterized, whereas SAH related to CO exposure has not been previously described. In this case report, the possible role of CO, either as a primary cause or as a facilitating factor, in the pathogenesis of SAH is discussed. In particular, we propose the hypothesis that the excessive vasodilating effects produced by CO on the cerebral endothelium results in consequential loss of microvascular integrity.     

Positive Dental Identification Using Tooth Anatomy and Digital Superimposition

Dental identification of unknown human remains continues to be a relevant and reliable adjunct to forensic investigations. The advent of genomic and mitochondrial DNA procedures has not displaced the practical use of dental and related osseous structures remaining after destructive incidents that can render human remains unrecognizable, severely burned, and fragmented. The ability to conclusively identify victims of accident and homicide is based on the availability of antemortem records containing substantial and unambiguous proof of dental and related osseous characteristics. This case report documents the use of digital comparative analysis of antemortem dental models and postmortem dentition, to determine a dental identification. Images of dental models were digitally analyzed using Adobe Photoshop^TM software. Individual tooth anatomy was compared between the antemortem and postmortem images. Digital superimposition techniques were also used for the comparison. With the absence of antemortem radiographs, this method proved useful to reach a positive identification in this case.     

Age Estimation in Indians Using Demirjian’s 8‐teeth Method

Abstract: Demirjian’s grading of tooth calcification is widely used to assess age of individuals with developing dentitions. However, its application on numerous populations has resulted in wide variations in age estimates and consequent suggestions for the method’s adaptation to the local sample. Conventionally, Demirjian’s method utilized seven mandibular teeth on the left side. A recent modification incorporated the third molar with a view to apply the method on a wider age‐group. Moreover, the revised method developed regression formulas for assessing age. This paper tested the 8‐teeth method using 547 Indians (348 females, 199 males) aged 7–25 years. Demirjian’s formulas resulted in inferior age prediction in Indians (9.2% misclassification at 99% confidence interval vs. 0% misclassification in the original study); therefore, India‐specific regression formulas were developed, which gave better age estimates (mean absolute error, MAE = 0.87 years) than the original formulas (MAE = 1.29 years). This suggests that Demirjian’s 8‐teeth method also needs adaptation prior to use in diverse populations.     

Crack Propagation in Teeth: A Comparison of Perimortem and Postmortem Behavior of Dental Materials and Cracks*

Abstract: This study presents a new method for understanding postmortem heat-induced crack propagation patterns in teeth. The results demonstrate that patterns of postmortem heat-induced crack propagation differ from perimortem and antemortem trauma-induced crack propagation patterns. Dental material of the postmortem tooth undergoes dehydration leading to a shrinking and more brittle dentin material and a weaker dentin-enamel junction. Dentin intertubule tensile stresses are amplified by the presence of the pulp cavity, and initiates crack propagation from the internal dentin, through the dentin-enamel junction and lastly the enamel. In contrast, in vivo perimortem and antemortem trauma-induced crack propagation initiates cracking from the external surface of the enamel toward the dentin-enamel junction where the majority of the energy of the crack is dissipated, eliminating the crack’s progress into the dentin. These unique patterns of crack propagation can be used to differentiate postmortem taphonomy-induced damage from antemortem and perimortem trauma in teeth.     

Age estimation of Korean adults by occlusal tooth wear

The aim of the present study was to evaluate the validity of the modified Kim's scoring system as a practical method of recording occlusal tooth wear and estimating age. For this purpose, 1092 pairs of maxillary and mandibular full-arch casts were randomly selected, scored, and analyzed. The results showed that the modified Kim's scoring system had excellent reliability, and that occlusal tooth wear had a positive correlation with age. Tooth wear scores of all teeth except the two lower central incisors were higher in males than in females. Calculating tables for age estimation were designed by multiple linear regression analysis. Estimated ages were within +/-5 years of actual ages in 63.5% of male subjects, and 64.0% of female subjects. The accuracy of age estimation was increased when the subjects were divided into two age groups and data were re-analyzed. Collectively, it was shown that the modified Kim's scoring system is a reliable and accurate method for age estimation, and that the data from these 1092 individuals can be used as a standard for age estimation of Korean adults.     

A Reappraisal of Developing Deciduous Tooth Length as an Estimate of Age in Human Immature Skeletal Remains

This study provides an update on a quantitative method for immature age estimation based on postnatal deciduous mandibular tooth length. Two known sex and age skeletal collections from Western Europe were sampled (n = 97). Linear regression models for age estimated were calculated for each individual tooth, each sex, and sex combined sample using classical calibration. Prediction errors, residuals, and percentage of individuals whose real age fell within the 95% prediction interval were calculated. The teeth which develop earlier in life, the incisors and the first molar, showed the greatest precision, while the canine showed the least. This method has greater applicability to archeological skeletons or to children in developing countries than for use in North American or European forensic contexts. The method can be applied to incomplete or poorly preserved remains of unknown sex, particularly when dental radiographs are not an option or when teeth have been removed from the alveolus or crypt.     

Reanalysis of Korean War Anthropological Records to Support the Resolution of Cold Cases

Re‐investigation of previously unidentified remains from the Korean War has yielded 55 new identifications, each with corresponding records of prior anthropological analyses. This study compares biological assessments for age at death, stature, and ancestry across (i) anthropological analyses from the 1950s, (ii) recent anthropological analyses of those same sets of remains, and (iii) the reported antemortem biological information for the identified individual. A comparison of long bone measurements from both the 1950s and during reanalysis is also presented. These comparisons demonstrate commonalities and continuing patterns of errors that are useful in refining both research on Korean War cold case records and forensic anthropological analyses performed using methods developed from the 1950s identifications.     

Age Estimation Based on Pulp Cavity to Tooth Volume Ratio Using Postmortem Computed Tomography Images

Pulp cavity size is known to decrease with age and can therefore serve as an indicator for age estimation. Here, we evaluated whether reconstructed images of multidetector‐row computed tomography (MDCT) acquired before forensic autopsy are useful for estimating age at death. Images of 136 mandibular first premolars obtained from bodies of known age at death were analyzed, and the volume of the regions corresponding to pulp cavity and that of the whole tooth were determined using a voxel counting function. The pulp cavity was clearly distinguishable from dental hard tissue on the reconstructed images when using a cutoff value of 1400 Hounsfield units. Regression analysis adjusted for sex showed that estimated age correlated significantly with the pulp cavity to tooth volume ratio (r = 0.76). MDCT is gaining more widespread use in forensic medicine, and analyzing dental images to obtain parameters for age prediction is a practical approach for postmortem identification.     

Assessment of the Role Played by N‐propanol Found in Postmortem Blood in the Discrimination Between Antemortem Consumption and Postmortem Formation of Ethanol Using Rats

This study disproves the reliability of n‐propanol as a biomarker to establish whether the ethanol found in postmortem blood is derived from antemortem ingestion or postmortem putrefactive processes. Two groups of rats were given ethanol or normal saline solution, respectively, and sacrificed 1.5 h later. After putrefaction, blood and, in a few cases, urine samples from the rats were analyzed for ethanol and n‐propanol by head‐space gas chromatography equipped with flame ionization detection. Although the concentration ratios of ethanol/n‐propanol in the postmortem blood collected from the bodies without prior alcohol consumption were expected to be <20 (as per limited case reports and previous in vitro studies), in samples from several rats that were on saline solution, this ratio was found to exceed 20. In conclusion, the concentration ratio of ethanol/n‐propanol in postmortem blood does not allow for the discernment between antemortem ingestion and the postmortem synthesis of ethanol.     

Usefulness of Forensic Dental Symbols© and Dental Encoder© database in forensic odontology

Abstract: A new universal graphic dental system, Forensic Dental Symbols^©, has been created to provide precision in the construction of dental records, improve standardization, and increase efficiency in dental identification procedures. Two hundred and thirty‐four different graphic symbols representing the most frequent clinical status for each tooth were designed. Symbols can be then converted to a typographic font and then are ready to use in any computer. For the appropriate use, manipulation, and storage of dental information generated by the Forensic Dental Symbols^©, Dental Encoder^© database has been created. The database contains all the information required by INTERPOL Disaster Victim Identification (DVI)‐dental‐forms. To explore the possibilities that Dental Encoder^© offers, an antemortem dental database from a Spanish population of 3920 military personnel had been constructed. Data generated by Dental Encoder^© were classified into sex and age groups. The program can perform an automatic search of the database for cases that match a selected clinical status presented in a single tooth or a combination of situations for several teeth. Moreover, Dental Encoder^© allows information to be printed on INTERPOL DVI‐dental‐forms, or the inclusion of any completed form into any document, technical report, or identification of dental report.     

Analysis of Bone Healing in a Postoperative Patient: Skeletal Evidence of Medical Neglect and Human Rights Violations

This study highlights complexities associated with postsurgical trauma interpretation of a 76‐year‐old female patient from a psychiatric institution in Mexico. The skeletal analysis identified complications from an unsuccessful surgical operation for an intertrochanteric fracture of the femur. An improperly placed surgical plate resulted in nonunion due to limited contact between fracture margins. However, it is unclear whether this resulted from surgical complications, ineffective postoperative care, or from the decedent's limited ability to follow postoperative care instructions. Additionally, failure of the plate resulted in degenerative changes to the acetabulum. These complications, associated with degenerative changes to upper limb joints, suggest significant mobility issues. The pattern of antemortem trauma and contextual information support a conclusion of postoperative medical neglect, a documented problem in psychiatric institutions in Latin America. This study provides insight into the relevance of detailed trauma assessment of skeletal remains in cases where neglect and human rights violations are suspected.     

Factors affecting postmortem tooth loss

Unassociated human bones are a particular problem during the exhumation of mass graves and a factor that limits anthropological and paleopathological analyses from archaeological contexts. Extensive anthropological literature has focused on the complex taphonomic factors that influences bone assemblages, but little attention has been paid to postmortem tooth loss and factors affecting this process. The following study focuses upon the influence of different factors on postmortem tooth loss. Three samples were investigated in the study: a medieval church cemetery containing 110 individual skeletal remains, and two samples from a series of mass graves made within the same time period in 1999, containing 402 bodies. The frequency of postmortem tooth loss was analyzed relative to postmortem interval for each sample, excavation methods, age distribution, and presence of bone loss associated with periodontal disease. Our results indicate that the degree of alveolar bone loss significantly affected both antemortem and postmortem tooth loss and that the frequency of postmortem tooth loss has the strongest correlation to time since death. These findings suggest that additional care should be taken when exhuming remains from older contexts.     

Measurements of the Foramen Magnum and Mandible in Relation to Sex Using CBCT

The purpose of this study was to evaluate pre‐existing CBCT images of a large sample of adult females and males to provide data on foramen magnum and mandibular measures of sexual dimorphism for use as a reference sample in cases of establishing identity in unknown fragmentary skulls. The study group consisted of 161 adult patients. 3D images of the patients were assessed retrospectively. FM measurements were obtained from reformatted axial sections. Six mandibular measurements were taken. According to the results, the study identified four mandibular measurements as final predictors of sex which are as follows: the gonial angle (G‐angle) and ramus length (Ramus‐L), gonion–gnathion length (G–G‐L) and bigonial breadth (BG‐Br). It was found that the cross‐validated grouped overall predictive accuracy was 83.2% for FM and mandible measurements. It could correctly identify males in 77.3% and females in 87.4% of the cases. To assess sexual dimorphism, the gonial angle and ramus, gonion–gnathion lengths, and bigonial breadth of the mandible and sagittal diameter of the FM may be used on CBCT images.     

Testing Discriminant Functions for Sex Determination from Deciduous Teeth*,†

Abstract: Three studies have proposed discriminant functions for sex determination from deciduous tooth crown dimensions, and this study tests the existing functions on a sample of 46 Portuguese immature skeletons of known sex, aged from birth to 10 years. Deciduous teeth were measured in their mesiodistal and faciolingual crown dimensions, and percentage of correct allocation accuracy in determining sex using each specific function was determined. Discriminant functions were also calculated from data collected for this study and tested using cross‐validation. Results show poor overall accuracy (33.3–75%) and poor cross‐validation (46.2–60.0%). This is related to low sexual dimorphism in deciduous tooth crown size, as well as differences in degree of sexual dimorphism and in overall tooth size between different samples. For these reasons, deciduous crown size does not seem to show significant forensic value as discriminator of sex, particularly when methods developed on one population are applied to individuals of another population.     

Detection of Tooth‐Colored Restorative Materials for Forensic Purposes Based on Their Optical Properties: An In Vitro Comparative Study

Victim identification using dental records involves antemortem and postmortem comparison of dental charts. Since dental restorations may be part of such records, identifying them accurately is critical. The objective of this study was to compare the diagnostic reliability and validity of two optical methods for identifying tooth‐colored restorations (digital imaging fiber optic transillumination (DiFOTI) using near infrared light, and fluorescence‐aided identification of restorations (FAIR)) with conventional diagnostic methods. Four examiners identified and charted tooth‐colored restorations in three sets of typodonts on the bench using conventional visual and tactile examination, DiFOTI (DIAGNOcam?) and FAIR. All examinations were repeated after 4 weeks. Both the sensitivity (95%) and specificity (97%) of the FAIR method were significantly higher than those for DiFOTI (82% and 82%) and for conventional inspection (71% and 82%). In conclusion, FAIR method performed better than conventional examination and DiFOTI, and was more reliable for identifying tooth‐colored restorations.     

Distinguishing Atherosclerotic Calcifications in Dry Bone: Implications for Forensic Identification

Atherosclerotic calcifications, as calcified atheromatous elements, are markers of cardiovascular disease. However, the literature gives little information regarding their morphological aspect, making their identification very rare in skeletonized cases. In this paper, we document the morphological, histological, and SEM aspects of atherosclerotic plaques collected from unclaimed cemeterial skeletal remains from an identified osteological collection and extracted from well‐preserved cadavers autopsied at the medico‐legal institute of Milan. Each of the three analyses provided similar results: atherosclerotic calcifications are convex‐concave plaques with a stratified structure, a pale‐yellow coloration in autopsy cases and yellow to brown when recovered in dry bone. Histologically, undecalcified and decalcified sections showed a stratified aspect formed by superimposed layers. Lastly, the SEM analysis showed a precise view of the stratified structure of the plaques in transverse section. As markers of disease, atherosclerotic calcifications can provide important antemortem information on the deceased that may be compared to antemortem data.     

Accuracy of BR Regression Equation for Impacted Teeth in Age Estimation in Haryana Population of India

Abstract:  Dental cementum is a vital tissue that demonstrates continuous apposition throughout the life of a tooth. Positive correlation has been reported between the coronal displacement of cementum and age in impacted teeth and BR regression equation has been proposed. The present study is an attempt to calculate accuracy of BR regression equation in Haryana population of India. The study was conducted on 20 impacted mandibular third molars extracted from healthy patients, aged between 22 and 32 years. The bucco-lingual ground sections were prepared and the distance between the edges of enamel and cementum were measured with micrometer attached to a light microscope and BR regression equation was applied for age estimation. Although the estimated age with BR regression equation was less than chronological age it was not statistically significant. Hence, the BR regression equation can be used in medicolegal as well as in forensic odontology for age estimation.     

The Use of Tooth Crown Measurements in the Assessment of Ancestry

As the hardest tissue in the body, teeth have the potential to offer a wealth of biological information to the forensic anthropologist, which can include the assessment of ancestry. Using a large data set of dental measurements, the efficacy of mesiodistal and buccolingual tooth dimensions to discriminate between broad, geographically based groups is explored. A general pattern is identified: African populations have the largest teeth, Asians possess teeth of intermediate size, and Europeans have the smallest teeth. In a discriminant function analysis using crown measurements of all teeth (mandibular and maxillary and excluding the third molar), individuals were correctly classified in 71.3% of cases. When the sex of the individual is known, classification is improved up to 88.1% in females and 71.9% of males (cross‐validated). Based on these results, we argue that dental metrics can be regularly employed as part of the development of the biological profile.     

Dental Age Estimation: A Test of the Reliability of Correctly Identifying a Subject Over 18 Years of Age Using the Gold Standard of Chronological Age as the Comparator

This study was designed to test the reliability of using the third molars to demarcate between child and adult status. A total of 2000 dental panoramic tomographs were used for assessment of the calculated age using the 8‐stage system of tooth development and applied to all four third molars. The LL8 was also assessed using this 8‐stage system. For each tooth development stage, the Normal distribution and percentile summary data were estimated. The calculated dental age compared with the chronological age was statistically significantly different (p < 0.001) for both females and males giving underestimates of the true age. Comparison of single tooth dental age and chronological age was only slightly different. The most important finding is that the assignment to above or below the 18‐year threshold, in the age range 17 years to 19 years, could be wrong on up to 50% of occasions.