Analysis of teeth exposed to high temperatures

Abstract

Background: In most cases, the complete destruction of soft tissues caused by heat can make difÏcult for forensic indentification of human remains. Fortunately, of their high resistant composition, hard tissues of human body are the most relatively well preserved after severe fire thus making it important source of information. The fact that in our country, there have been many cases of deaths in fires, and apparent lack of research on heat related changes in teeth subjected to high temperature, made necessities this type of study. Method: A total of 60 permanent teeth were studied. The samples were burned to temperatures of exposure, 100℃, 300℃, 500℃, 700℃, for 30 minutes. Before and after each exposure, periapical radiographs were taken and changes were analyzed. The statistical result was calculated by SPSS 25.0 program. Result: The study involved 42 participants, ages 18-72, with a male and female ratio of 1:1.6. No significant changes were observed in the 15 teeth of the group burned at 100℃. At 300℃, 87% of cases were anatomically preserved, and the rest lost their anatomical integrality. On the hard tissues of all burned teeth 2-7 fracture lines with 1.90±0.97 mm in length and 0.11±0.03 mm in width were determined. In 67% of cases, fracture lines were observed only in dentin, and in 33% fracture lines involved both the enamel and dentin. It was determined that 67% of the all teeth had a 0.29±0.12 mm separation in dentin-enamel junction. All teeth burned at 500℃ had lost their anatomical integrality. In 67% of cases, the crown of tooth was not visualized as it was completely fragmented and lost. As the rest, root with crown’s small portion of enamel and dentin were observed. On the hard tissue of all burned teeth 1-5 fracture lines were observed. The fracture lines were 1.91±1.39 mm in length and 0.13±0.59 mm in width. It was not possible to determine dentin-enamel junction as the reference points were destroyed due to microfractures. All teeth burned at 700℃ had lost their anatomical integrality. In 47% of cases, complete disintergration of the crown occurred, only the root remained. As the rest, root with small portion of coronal dentin were observed. In 97% of cases, 2-13 fracture lines with 1.48±0.98 mm in length and 0.17±0.07 mm in width were determined. When statistically analyzed fracture lines with exposing temperature, the number of fractures lines (r=0.32, p<0.05) and width (r=0.36, p<0.01) increases as temperatures raises. But length of fractures line shows statistically not significant relationship with exposing temperature (r=-0.17, p<0.01). Conclusion: 1. When the teeth are exposed to high temperatures, alterations may develop in enamel, dentin, and dentin-enamel junction with root and crown fractures. 2. Changes in tooth structure are likely to increase (p<0.05, p<0.01) as temperature progresses.