Mitoses and microorganisms in the periodontal membrane after storage in milk or saliva.

Milk and saliva were tested in vitro as potential storage media for avulsed teeth. Developing monkey teeth were extracted and stored in milk or saliva for periods ranging from 1 to 6 h. The osmolality, pH, conductivity and number of viable bacteria in the media were determined after predetermined intervals during the storage periods. After the storage periods the teeth were either prepared for scanning electron microscopy or cultured for 24 h in Eagle's medium supplemented with 3H-thymidine. In the scanning electron microscope numerous adherent bacteria were seen covering the periodontal membrane after storage in saliva but none were found after storage in milk. The cultured teeth were sectioned and evaluated with autoradiography. Superficial parts of the periodontal membrane were rapidly injured by storage in saliva while the epithelial root sheath and the apical pulpal cells were affected at a later stage. Cells neighboring the cementoblasts incorporated 3H-thymidine after 6 h storage in milk but not after storage in saliva for the same length of time. It was concluded that the low osmolality in combination with bacteria which adhered to the periodontal membrane made saliva less suited than milk for long time storage of avulsed teeth. Furthermore, a viable layer of cells close to the root surface seemed to be a prerequisite for a successful healing without root resorption after replantation.