Abstract: Objective To probe the correlation between the postmortem interval (PMI) and the DNA degradationof costicartilage and dental pulp cells in human being after death ,and to seek a new method for estimating PMI.Methods The image cytometry was used to measure the DNA degradation under different ambient temperatures(30- 35℃,15- 20℃) in 0- 15 days after death. Results The average DNA content of two kinds of tissue wasdegradated with the prolongation of PMI. But there was a plateau period of 0～4 days for dental pulp cells ofhuman being in 15～20℃.There was a high negative correlativity P<0.01 between the average DNA content andPMI. Conclusion PMI could be estimated accurately according to the DNA degradation of costicartilage anddental pulp cells in human being after death.

Key words: postmortem interval, dental pulp, costicartilage, DNA degradation