[Studies on sex determination using human dental pulp. II. Sex determination of teeth left in a room].

The appearance rate of Y chromatin was calculated in the dental pulp with the staining by Quinacrine Mustard. The morphological findings of the tissue were observed with the HE stained section and the change of the appearance rate of Y chromatin was studied along with the morphological change of the tissue. The average of the appearance rate of Y chromatin in the male dental pulp was 42.2% immediately after the tooth extraction, 34.8% after one month, 27.9% after 3 months, 20.8% after 6 months, 20.6% after 1 year, 19.1% after 18 months and 11.4% after 2 years, respectively. On the other hand, the appearance rate of the pseudo-Y chromatin spot in the female pulp was below 4.2% through the two years' observation which enabled to determine the sexuality. By the HE staining observation about the dental pulp, left at a room temperature, it was revealed that the pulp tissue can be well preserved for a long time because of the natural drying. The degree of the staining declined with the lapse of time after the removal of tooth. Degeneration of tissue did not offer any discrete criteria for the estimation of the lapse of time after the removal of tooth.