Estimation of time since death based on light microscopic, electron microscopic, and electrolyte analysis in the gingival tissue

Abstract

Background:Estimation of time since death is an important parameter in forensic science. Although there are various methods available, precise estimation is still to be established.Aim:The present study aimed to evaluate the histological and ultrastructural changes in the gingival tissue along with the changes in electrolyte levels (sodium, potassium, calcium, and magnesium) among the three groups which included normal, 2, and 4 h since death.Materials and Methods:For light microscopic examination and electrolyte analysis, five normal gingival tissue samples were collected from patient following impaction procedure and five gingival tissue samples were obtained from postmortem specimen at 2 and 4 h since death. Each sample was divided into two parts. The first part was fixed in 10% formalin solution for the light microscopic analysis, and microscopic changes were observed between the groups. The second part was snap frozen at −80°C, until measurement of electrolyte using inductively coupled plasma-optical emission spectrometer, and the values were compared among the groups using Kruskal–Wallis test. For electron microscopic examination 2 and 4 h postmortem, gingival tissue samples were collected from the same individual and immediately fixed in 2.5% buffered glutaraldehyde, and the ultrastructural changes were compared with the normal gingival tissue.Results:The light microscopic changes were observed as early as 2 h since death, but there was no significant difference observed between 2 and 4 h postmortem samples whereas ultrastructurally significant difference in morphology was observed between 2 and 4 h postmortem gingival tissue. Our results can confirm histomorphological changes within 2 and 4 h since death.

The Potential of Light Microscopic Features of the Oral Mucosa in Predicting Post-mortem Interval

“…15 In comparison, other researchers have compared antemortem and post-mortem mucosal samples to determine post-mortem cellular changes. 7,8,10,16 Three studies have been conducted to associate changes in salivary gland oral mucosa with time since death. 11,12,20 Based on evaluations of the cellular changes in antemortem and post-mortem mucosa, Gururaj suggested that the decomposition process begins in the initial 24 hours, while Pradeep et al concluded that the decomposition process at the cellular level begins within 10 hours of death.…”

“…8 In a recent study, Muthukrishnan et al described early and late postmortem changes in five antemortem and five postmortem gingival samples. 10 Due to sample size limitations, none of the aforementioned studies were able to provide statistical confirmation of the usefulness of light microscopic cellular changes in the oral mucosa as a method of predicting time since death. [9][10][11]15,20,21 Moreover, several studies either evaluated post-mortem cellular changes in the gingiva alone or in the labial mucosa.…”

“…10 Due to sample size limitations, none of the aforementioned studies were able to provide statistical confirmation of the usefulness of light microscopic cellular changes in the oral mucosa as a method of predicting time since death. [9][10][11]15,20,21 Moreover, several studies either evaluated post-mortem cellular changes in the gingiva alone or in the labial mucosa. 7,8,15 No studies have yet sought to assess the role of these changes in the buccal mucosa.…”

“…7 Degenerative post-mortem changes to the epithelium and connective tissue in the oral mucosa may demonstrate specific patterns that could prove useful to determine PMI; however, few studies have sought to evaluate post-mortem cellular changes in the oral tissues including the gingiva, salivary glands and dental pulp. [7][8][9][10][11][12][13][14] Moreover, inadequacies in terms of sample size and standardised methodology have often precluded confirmation of this approach. Therefore, the current study aimed to investigate post-mortem light microscopic cellular changes in the oral tissues with the objective of estimating their potential for PMI prediction.…”

Métodos Histoquímicos e Inmunohistoquímicos para la Estimación del Intervalo Postmortem en Tejidos Humanos: Una Revisión

“…La evaluación de tejidos provenientes de la cavidad oral para estimación del IPM se focalizó en 3 estudios detectados en esta revisión, aplicando métodos IHQs en mucosa labial (Charan Gowda et al) y tejido gingival (Fais et al; Mazzotti et al). Eso se suma a la tendencia iniciada años antes con propuestas de evaluaciones de cambios histológicos para estimar el IPM en esos mismos tejidos (Pradeep et al, 2009;Yadav et al, 2012;; Mahalakshmi et al, 2016;Muthukrishnan et al, 2018). Yavad et al (2015), afirman que existe mucha información publicada respecto a los fenómenos postmortem en tejidos orales, lo que podría restringir el rol de los médicos forenses al momento de estimar el IPM.…”