Regeneration of the Ruffini Endings in the Replanted Rat Incisor with the Application of Emdogain® Gel

We examined the effect of Emdogain (R) Gel (EMD) on the regeneration of periodontal tissue and demonstrated immunohistochemical changes of nerve fiber and mechanoreceptors in the repairing of periodontal ligament (PDL) of a rat replantation model. Maxillary right incisor of male Wistar rats was extracted. After removing pulp tissue from root apex side, the intracanal was filled with warmed gutta-percha by retrograde root canal filling. In the experimental group (EMD group) was used EMD at 0.05ml to root surface before replantation. Untreated group (UT group) was replanted immediately. The samples were extracted on day 3 and at 1, 2 and 4 weeks after surgery. The samples were stained with hematoxylin and eosin (H. E), immunostained with protein gene product 9.5 (PGP 9.5) and Na+, K+ -ATPase beta 1 fusion protein (Na+, K+-ATPase). In EMD group was recognized continuing recovery of PDL more quickly than UT group at 1 week. In the EMD group, islet-shaped bones were hypertrophied in the PDL at 1 week. And Na+, K+-ATPase positive reaction which demonstrated recovery of the mechanoreceptors activation was recognized to the Ruffini endings at 1 week. In EMD group was recognized more hypertrophy of alveolar bone at the periradicular than UT group at 2 weeks. In both groups, the constriction of PDL space and the sectional root absorption were recognized at 4 weeks. In conclusion, the continuity of the PDL fiber and the activity of the ruffini endings showed early recovery by applying EMD to the tooth replantation of rat. Bone development was started early even with the PDL and the periradicular alveolar bone. However, the application of EMD couldn't prevent the constriction of PDL space and the root absorption.