Effect of drying on viability of periodontal membrane.

The influence of a dry extra-alveolar period on the viability of cells in the periodontal membrane of human and monkey teeth was examined in vitro. Extracted mature teeth were allowed to dry for 0, 30, 60, 90, and 120 min. Cell viability was examined with the following methods: 1) Culturing the teeth with subsequent typsination and counting of viable cells. 2) Culturing the teeth with subsequent vital staining of the root surface with neutral red and estimation of the vital stained periodontal membrane area in percentage of the total root surface. Both methods revealed that the number of viable cells in the period declines very rapidly with an increase in drying time. After 2 h it was not possible to demonstrate cell viability using tissue cultrue technique.