Effects of elevated temperatures on different restorative materials: An aid to forensic identification processes

Forensic exploration of endodontic cements: Unveiling macroscopic and radiographic changes under high temperatures

OBJECTIVE

To evaluate macroscopically and radiographically the behavior of four endodontic sealers submitted to high temperatures, with forensic purposes.

METHODS

Sixty-four lower anterior teeth were included. All teeth were endodontically treated, and simulation of external cervical resorption (ECR) was performed. Half of the sample was filled with AH-Plus™ cement and had ECR sealed with Bio-C-Repair™. The other 32 teeth were filled with Bio-C-Sealer™ cement and had their respective ECR sealed with MTA-Repair™. Then, all teeth were introduced into a bovine bone block to simulate the alveolar bone. The teeth were submitted to incineration at temperatures of 600, 800, 1000, and 1140 °C. All teeth were radiographed before and after incineration. The pre-and post-incineration radiopacity of cements and dentin were evaluated using the ImageJ™ software and compared using a t-test for paired samples.

RESULTS

It was possible to confirm color change and appearance of cracks in the tissues and dental materials tested, varying according to the temperature. Radiographically, it was observed that the dental crowns completely detached at 1000 ° and 1140 °C, and, only at 1140 °C, the roots showed cracks. Regarding the radiopacity, there was a significant difference in the shades of gray in AH-Plus™ when subjected to 1000 ° and 1140 °C, and at 600 ° and 1000 °C in Bio-C-Sealer™. In Bio-C-Repair™ and MTA-Repair™, a difference was observed at 600 ° and 1140 °C.

CONCLUSIONS

There were macroscopic and radiographic alterations of the materials. This data is important in Forensic Dentistry and may contribute to identifying carbonized victims.

R. V, Mony V. Histomorphologic and Gravimetric Changes of Teeth Exposed to High Temperature - <i>In vitro</i> Study

Background: In forensic dentistry, odontologists have been particularly interested in the investigation of burnt human remains. The purpose of our research is to provide morphological, stereomicroscopic, histological, and gravimetric findings from the investigation of the effects of thermal processes on teeth.Teeth, being the hardest substance in the body, give valuable information for forensic analysis. Objective: Histomorphology and gravimetric changes in teeth exposed to different ranges of high temperatures. Methodology: Thirty-six mandibular premolar teeth extracted for therapeutic purpose were taken and exposed to the varying higher temperatures. Macroscopic, stereomicroscopic, histological analyses along with the dry weight estimation were recorded at each temperature gradient. Results: From a lower temperature to a higher temperature, the specific colour change of the tooth was yellowish-orange, metallic black bronze and chalky white. Stereo microscopically, we observed intact teeth at 100°C; the gradual formation of micro cracks, crown-enamel separations from the cervical margin, eggshell cracking at 500°C; and a completely shattered crown at 900°C. Decalcified sections show dilation in the dentinal tubular pattern at 300°C. Loss of typical architecture was noted at 400°C, with dentinal tubules exhibiting the vapor bubble appearance. In-ground section alterations on the scalloping nature of dentino enamel junction, coalescing radicular dentinal tubules and sand cracking appearance of the tooth were noted at 100°C, 300°C and 900°C, respectively. Significant reductions in the weight of the teeth samples were observed with higher temperatures. Conclusion: Incineration-induced morphologic, histologic, and gravimetric alterations may provide useful information regarding the temperature and duration of fire exposure. It might also assist in understanding the conditions of the fire.

Forensic Identification of Endodontically Treated Teeth after Heat-Induced Alterations: An In Vitro Study

Objective:

The study aimed to highlight the relationship between forensic science and endodontics by illustrating CBCT records can be used as legal evidence for forensic analysis and evaluate the effect of elevated temperature on the endodontically treated teeth.

Methods:

The present study was conducted on 40 extracted permanent mandibular premolars, which were divided into two groups based on predetermined incineration temperature: Group I - 400°C & Group II - 800°C subjected for 15 minutes holding time in a digital burnout furnace. The root canal treatment was performed for both the groups and a Pre-incineration CBCT scan was taken for both the groups as an ante-mortem data. Following heating analysis, root canal treated teeth were examined using a stereomicroscope at 20x resolution to evaluate the morphological changes. The post-incineration CBCT scan was taken as the post-mortem record for each group. Both ante-mortem records and post-mortem records were compared for the forensic analysis.

Results:

The endodontically treated teeth display a series of macroscopic and stereo-microscopic changes for each temperature scale. The CBCT records identify the thermal stress-induced 3D alterations in the gutta-percha filled teeth.

Conclusion:

Knowledge of changes in human dentition and traces of the endodontically treated teeth can help forensic experts for the identification of the fire victims.

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.

Charred: Forensic dental identification and scanning electron microscope

The identification of bone and dental remains to establish identity, requested by police and judicial authorities, has increased annually because criminals have been using sophisticated methods that make this identification impractical. This study reports a murder case by charring, which creates dental and bone calcination. In 2013, a completely burned car was examined by forensic experts, containing charred, calcined human bones and teeth inside its trunk, thus an identity needed to be established. The scanning electron microscope (SEM) was used as a supporting method and indicated the presence of restorative materials, which were compatible and consistent with the chart and radiographic shots provided by the victim's dental surgeon. The SEM examination reinforced the positive identification of the alleged victim performed by comparative radiographic examinations (antemortem and postmortem) in the dental fragments found. It is a supporting method that, even though it does not establish the identity, it helps in the process of identification.

Adjunctive role of dental restorations in personal identification of burnt victims

Background:

Fire remains one of the major causes of morbidity and mortality throughout the world and identification of a body from the fatal fire remains a daunting task. Several forensic cases involve interpretation of burnt human bodies from airline and automobile accidents, bombings and unlawful cremation. Fire is also involved in homicides, suicides, accidental death, arson and in attempts to destroy forensic evidence in criminal cases. Soft tissue destruction from fire can be so extensive that conventional methods of identification may be impossible. However, teeth survive even high temperatures due to their resistant composition and so, obviously, the restorative material housed in the teeth are even more secure and can yield valuable information in personal identification.

Aim:

To assess the usefulness of most common restorations in personal identification in burnt cases.

Materials and Methods:

The study was conducted on 40 extracted teeth which were divided into four groups (Group 1 - Unrestored teeth, Group 2 - Amalgam restored, Group 3 - Glass ionomer restored and Group 4 - Composite resin restored teeth. The effect of incineration at 200°C, 400°C, 600°C, 800°C, 1000°C for 15 min at each target temperature followed by subsequent cooling was studied.

Results:

Amalgam restoration was resistant and intact even at 1000°C, whereas GIC and composite restoration are identifiable till 600°C, the residual cavity preparation leaves a clue for narrowing down the spectrum of identification.