[The experimental study of the delayed replantation after cryopreservation of mature tooth in dogs].
OBJECTIVE
To study the conditions of healing of mature tooth in dogs after long cryopreservation followed by replantation.


METHODS
The tooth was extracted after filling the root canals and then preserved for one week and three months respectively by Schwartz's method of cryopreservation of periodontal membrane. The specimens were took out eight weeks after replantation. It was demineralized in a 5% solution of formic acid,and then sectioned perpendicular to the long axes of tooth at a thickness of 5microm. The tooth were sectioned in step-serial sections at 500 microm intervals. The sections were stained with hematoxylin-eosin and followed by evaluation according to Andreasen.


RESULTS
The percentage of healing of periodontal membrane (PHPM) of the group of cryopreservation for one week was 64.53%. It was lower than the PHPM of the group of immediate replantation (85%), but the difference demonstrated no significance (P>0.05). The PHPM of the group of cryopreservation for three months was 50.3%. It was lower than the PHPM of the group of immediate replantation significantly (P<0.05).


CONCLUSIONS
The human's periodontal membrane may be cryopreserved longly and heals after the replantation of tooth as the human's tissues of corneas, skin, islets, et al may be done. The alveolar cavities to be newly made affect the healing of periodontal membrane in some degree.
College of Stomatology, Tongji University, Shanghai 200072, China.
L X
LX
Yin
K F
KF
Pan
L
L
Wang
J L
JL
Wang
J D
JD
Yang
P Y
PY
Ge
P
P
Wang