title: Assessment of histological changes in antemortem gingival tissues fixed at various time intervals: A method of estimation of postmortem interval.
abstract: BACKGROUND
  Conventional methods to estimate the time of death are adequate, but a histological method is yet unavailable to assess postmortem interval (PMI). The autolytic changes that occur in an unfixed antemortem gingival tissue which reflects histologically at an early stage are similar to changes that occur in postmortem tissue. These histological changes can be used and applied in a postmortem tissue as a method to assess PMI.
  
  
  OBJECTIVE
  The aim of the study is to assess the histological changes in a gingival tissue left unfixed for various time intervals and to correlate the findings with duration.
  
  
  METHODS
  Sixty gingival tissues obtained from patients following therapeutic extractions, impactions, gingivectomy and crown lengthening procedures were used. Each tissue obtained was divided into two pieces and labeled as "A", the control group and " B" the study group. Tissues labeled "A" were fixed in 10% formalin immediately and tissues labeled"B" were placed in closed containers and fixed after 15, 30, 45 min, 1, 2, and 4 h time interval. Of the sixty tissues in the study group " B", ten tissues were used for each time interval under investigation. All the fixed tissues were processed, stained, assessed, and analyzed statistically using Pearson correlation and regression analysis.
  
  
  RESULTS
  Histological changes appear at 15 min in an unfixed antemortem tissue. At 2 h interval, all layers with few cells in basal cell layer are involved. At 4 h interval, loss of stratification and complete homogenization of cells in the superficial layers with prominent changes in basal layer is evident. There was a positive correlation (<1.0) between the time interval and the appearance of the histological changes.
  
  
  CONCLUSIONS
  Histological changes such as complete homogenization of cells in superficial layers and loss of epithelial architecture at 4 h in unfixed antemortem tissue may be used as a criterion to estimate PMI, after further studies on postmortem tissues.
authors.affiliation: Department of Oral Pathology and Microbiology, C.S.I. College of Dental Sciences and Research, Madurai, India.
authors.forename: V
authors.initials: V
authors.lastname: Mahalakshmi
authors.affiliation: Department of Oral Pathology and Microbiology, C.S.I. College of Dental Sciences and Research, Madurai, India.
authors.forename: N
authors.initials: N
authors.lastname: Gururaj
authors.affiliation: Department of Oral Pathology and Microbiology, C.S.I. College of Dental Sciences and Research, Madurai, India.
authors.forename: R
authors.initials: R
authors.lastname: Sathya
authors.affiliation: Department of Oral Pathology and Microbiology, C.S.I. College of Dental Sciences and Research, Madurai, India.
authors.forename: T R
authors.initials: TR
authors.lastname: Sabarinath
authors.affiliation: Department of Oral Pathology and Microbiology, Meenakshi Ammal Dental College, Chennai, Tamil Nadu, India.
authors.forename: B
authors.initials: B
authors.lastname: Sivapathasundharam
authors.affiliation: Department of Oral and Maxillofacial Surgery, C.S.I. College of Dental Sciences and Research, Madurai, India.
authors.forename: S
authors.initials: S
authors.lastname: Kalaiselvan
keywords: Autolysis; homogenization; postmortem interval