Dental methods of post-mortem interval estimation. A pilot study on Feulgen reaction for DNA integrity on teeth pulp

The estimation of late post-mortem intervals (PMIs) represents a challenge for the routine forensic pathologist's practice. Few studies have evaluated the reliability of teeth as stable and protected matrices rich in DNA. The pilot study aims to verify the feasibility of Feulgen reaction colorimetric measurement on odontoblastic cells from the dental pulp of extracted teeth as a useful tool to estimate late PMIs. Ten teeth obtained from healthy patients who underwent tooth avulsion for clinical reasons were included in the sample and crown pulps were extracted at five different PMIs (T0-baseline, 14 days, 1 month, 1.5 months, and 2 months). The PMI was assumed as the time elapsed from the tooth avulsion up to the pulp extraction. The Feulgen reaction and the colorimetric analyses with ImageJ software on odontoblastic cells of dental pulps were pursued in order to measure the residual dental DNA integrity according to the PMls. The study provides evidence for the persistence of odontoblasts up to 2 months post-mortem in a recognizable organization, hence useful in late PMIs. The method based on Feulgen reaction could be a reliable tool for estimating the late PMI, correctly distinguishing between PMI 0 and 14 days, but also between PMI 14 days and 2 months. To the best of our knowledge, the Feulgen reaction has never been applied to study the possible correlation of the dental pulp cells' integrity and the PMI. Preliminary results suggest the feasibility of the proposed method for estimating the time elapsed since death, but further research is needed.