Murine tooth organ transplantation after in vitro culture

The development of mandibular molar tooth germs isografted in the mouse spleen

Tooth germs taken from 13-day-old embryonic mice and isografted in the spleen of adult mice were examined by light and electron microscopy. Well-organized tooth structures from the early cap stage to fully developed and mineralized mature teeth were obtained up to day 60 after transplantation. Germs on day 2 were similar to those prior to the onset of grafting but reached the late cap stage of development on day 4. On day 6, enamel and dentine formation were initiated and inner enamel epithelium and dental papilla cells were polarized. On days 10-15, enamel-matrix secretion was completed and almost all ameloblasts had become resorptive enamel epithelium. India ink injected from the recipient caudal vein accumulated to the capillaries within the pulp throughout the newly-formed vessels. On day 20, defined root formation had begun but occasionally irregular and cellular osteodentine was formed in root areas. On day 30, transplants were covered with reduced enamel epithelium and acellular cementum was formed at the root areas together with rudimentary periodontal ligament fibres. Cellular cementum became thicker up to day 40. There was little evidence of cellular infiltration from recipient tissue up to day 60. The spleen seems to be a suitable site for transplantation of tooth germs.

Influence of serum on cultured murine tooth organ allotransplants

Previous investigations indicated that in vitro culture of fetal tooth germs before allotransplantation prolonged graft survival. This study assessed the influence of different sources of serum in culture medium on post-transplant development of neonatal tooth organs. The results indicate that recipient-strain serum, but not donor-strain serum or calf serum, increased tooth survival compared with that of uncultured controls, which were rejected by the fourteenth post-transplant day. The survival curve for cultured tooth organs was shifted to the right by two days. No tooth transplant survived beyond three wk.