Analysis of heat induced changes in dental tissue for forensic application: A scanning electron microscope study

Introduction: In the forensic field, having accurate understanding of the macroscopic and microscopic alterations that occur in teeth when exposed to temperatures has remarkable significance. The preservation of delicate incinerated teeth is crucial in fire investigations that pertain to the temperature exposed, as well as the identification of victims. This preservation is necessary in order to conduct macroscopic and microscopic ultra-structural examinations, which provide valuable insights into the structural alterations that dental tissues undergo when exposed to low to high temperatures.

Aim: To analyze the macroscopic changes and the microscopic ultra-structural changes of dental hard tissue in permanent and deciduous dentition using stereomicroscope and scanning electron microscope (SEM).

Materials and methods: The study was conducted on 40 healthy freshly extracted teeth (20 permanent and 20 deciduous) which were subjected to predetermined temperatures i.e., 200̊C, 400̊C, 600̊C and 800̊C respectively for fifteen minutes using muffle furnace. Teeth were examined under stereomicroscope, later which they were processed for SEM examination at a magnification of 1000×. The parameter for macroscopic observation is colour, translucency and surface texture of enamel and cementum. The parameters used in microscopic observation of enamel such as pit and fissure morphology, prism pattern, crack/fracture lines, microporosity, debris, erosion, while for cementum, the parameters considered were crack presence, fissure morphology, collagen bundle arrangement, pattern, and debris. Both macroscopic and microscopic observations of dentition at different specific temperatures were calculated using percentage. The difference in macroscopic and microscopic changes between permanent and deciduous teeth were analyzed using chi-square test.

Results: There was no significant correlation in macroscopic and microscopic changes between permanent and deciduous teeth. Observations of dentition at various specific temperatures, both at the macroscopic and microscopic levels, revealed a noticeable reduction in the presence of each of the selected parameters in enamel and cementum.

Conclusion: The study revealed significant macroscopic morphological alterations and consistent microscopic ultra-structural patterns alterations that were readily observable at specified temperatures. The use of scanning electron microscopy (SEM) in the examination of burnt dental remains has a special potential for enhancing victim identification and advancing the field of forensic odontology.