Scanning electron microscopic analysis of incinerated teeth: An aid to forensic identification

Interglobular dentine attributed to vitamin D deficiency visible in cremated human teeth

Vitamin D deficiency has hugely impacted the health of past societies. Its identification in skeletal remains provides insights into the daily activities, cultural habits, and the disease load of past populations. However, up till now, this approach remained impossible in cremated bones, because temperatures reached during cremations destroyed all macroscopic evidence of vitamin D deficiency. This precluded the analyses of a large fraction of the archaeological record, as cremation was an important burial ritual from the Late Neolithic until the Early Medieval period in Europe. Here, the identification of interglobular dentine (IGD), a dental mineralisation defect attributed to vitamin D deficiency, in experimentally burnt teeth, demonstrates this deficiency to be observable in human teeth burned to temperatures as high as 900 °C. In most cases, it becomes even possible to assess the ages-of-occurrence as well as the severity of the IGD and possibly vitamin D deficiency intensity. This study represents a major step forward in the fields of biological anthropology, archaeology, and palaeopathology by opening up a variety of new possibilities for the study of health and activities related to sunlight exposure of numerous past populations that practiced cremation as their funerary ritual.

An Ultrastructural Study on the Effect of High Temperatures on Teeth and Restorative Materials That Aids in the Identification of Human Remains

Introduction

In most disasters, teeth are the only means of positive identification of an otherwise unrecognizable body, as there has been tremendous increase in the use of dental restorations that have different resistance to prolonged high temperature which is an important aid in identifying burned victims. Application of SEM/EDS in forensics was found useful in areas where there is a need for good imaging with high magnification combined with elemental analysis. The objective of this study was to analyze incineration effects on teeth and restorative materials using SEM/EDS. Materials and Method. 128 extracted teeth were collected, 96 were restored with silver amalgam, composite, and GIC of 32 each, and crown preparation was done in 32 teeth for which metal ceramic crowns were prepared. These teeth were subjected to 4 different temperatures (500°C, 700°C, 900°C, and 1100°C) for 20 minutes, and they were analyzed macroscopically and by using SEM for the changes subsequent to their exposure to such high temperatures.

Results

All the restorations which were very difficult to identify by naked eye were identified with the help of SEM/EDS.

Conclusion

Elemental analysis of the specific restorative material proves to be an essential tool for the forensic odontologist.

Use of XRD and SEM/EDX to predict age and sex from fire-affected dental remains

In fire scenarios, the application and accuracy of traditional odontological methods are often limited. Crystalline studies and elemental profiling have been evaluated for their applicability in determining biological profiles (age and sex) from human dentition, particularly fire- and heat-affected dental remains. Thirty-seven teeth were paired according to tooth type and donor age/sex for the analysis of crown and root surfaces pre- and post-incineration using X-ray diffraction (XRD) and scanning electron microscopy (SEM/EDX). In unburned crowns, carbon (C) content showed a positive correlation with age, whereas phosphorus (P) and calcium (Ca) contents showed a negative correlation with age. In unburned roots, C, P and Ca contents also showed significant changes that were opposite of those observed in the crowns. In relation to sex, females exhibited a higher C ratio than males, whereas males showed significantly higher levels of oxygen (O), P and Ca in unburned roots. Incineration resulted in an increase in the crystallite size that correlated with increasing temperature. No differences in hydroxyapatite (HA) crystallite size were found between age groups; however, unburned teeth from females exhibited a larger crystallite size than did those from males. The challenges of using XRD with a 3D sample were overcome to allow analysis of whole teeth in a nondestructive manner. Further studies may be useful in helping predict the temperature of a fire.

Ultrastructural Analysis of Incinerated Teeth by Scanning Electron Microscope - A Short Study

INTRODUCTION

In forensic context precise knowledge on physical and histological changes of teeth subjected to high temperatures is of great importance. Preserving fragile incinerated teeth for physical, histological and ultra structural examinations is essential in fire investigations involving the origin of fire, its cause as well as the identification of victims which relies on a thorough understanding of the structural changes in dental tissues subjected to heat.

AIM

The study was conducted to evaluate the physical and ultrastructural changes seen in freshly extracted teeth when subjected to gradual heating at different temperatures using Scanning Electron Microscope (SEM).

SETTINGS AND DESIGN

Freshly extracted teeth collected from subjects of different age groups were subjected to different temperatures using laboratory furnace and findings were correlated to the temperature.

MATERIALS AND METHODS

The study was conducted on 60 healthy freshly extracted teeth belonging to age group between 20-30 years. Group A comprised of control group which included teeth that were not subjected to heat whereas Group B, C and D comprised of teeth that were subjected to different temperatures i.e., 100(o)C, 300(o)C and 600(o)C respectively for a time of fifteen minutes in laboratory furnace, after which they were processed for SEM examination. Each group included 15 teeth; 5 anteriors, 5 premolars and 5 molars.

RESULTS

Examination under SEM revealed definite ultra structural changes which were explicitly seen at particular temperatures (100(o)C, 300(o)C and 600(o)C). The samples showed cracks and charring of the tooth structure with ultra structural findings such as pebbles, granules, dots on enamel surface; and soap bubble pattern, honey comb pattern and snail track pattern on cementum surface.

CONCLUSION

Because of the consistency of morphological changes and the ultra structural patterns at various temperatures, evaluation of incinerated dental remains using SEM can provide additional investigative avenues in victim identification and in the areas of forensic fire investigations.