Characterization of histomorphological and microbiological changes in tooth pulp to assess post-mortem interval: an observational study

The rate of decomposition of the organs of the body has been widely studied by forensic pathology experts for the determination of time elapsed after death. But researches pertaining to the dental pulp organ have been very sparse. This study attempts to identify the morphologic and microscopic characteristics of the tooth pulp for over a time period of 2 years with respect to time elapsed since its designated death. Eight experimental groups consisting of 5 extracted teeth in each group were constituted. The apical foramen was blocked with modeling wax. In groups 1, 2, 3, 4, 5, 6, 7, and 8, dental pulp was extirpated after 24 h, 48 h, 72 h, 1 month, 3 months, 6 months, 1 year, and 2 years of extraction, respectively. The pulp tissue underwent a standard histological processing and hematoxylin and eosin (H & E) staining. Slides were observed under a light microscope. Morphologically, the color of the pulp changed from pink at 24 h to pale pink by 72 h. The consistency ranged from soft to firm to jelly by 72 h and later became desiccated and friable by 2 years. Microscopically, a rapid degeneration in the constituents of pulp was seen until 72 h followed by slowing down beyond 1 month with less histologic variations. Smaller vacuolations were observed in a 24-h PMI pulp which progressively increased filling up the entire stroma by 2 years. The nuclei underwent a series of autolytic changes with increasing time. The odontoblastic layer was seen in some areas for up to 6 months. Microbiological assessment showed Gram-positive staphylococci and streptococci up to 2 years Estimation of post-mortem interval (PMI) changes in pulp, which is enclosed in a hard structure, composed of enamel and dentin provides the advantage of being studied up to 2 years as compared to other organs. Progressive degradation of the matrix and cellular constituents of the pulp with increased vacuolations were noted in our study, and evaluation of these characteristics can be a cost-effective and simplified additional tool to estimate the PMI.