Abstract
The aim of this study was to use immunohistochemistry to characterize apical peri-implant epithelium (aPIE) newly formed along the dental implant interface after implantation and peri-implant connective tissue of rats.
Titanium implants, 2 mm in diameter and 5 mm in length, were surgically implanted in the palatal region of rats. Animals were sacrificed at 3, 7, 14 and 28 days after implantation. Paraffin sections were cut and HE and immunohistochemical staining was performed, using primary antibodies to laminin-5, CK13, PGP9.5 and Von Willebrand Factor.
At 3 days after implantation, no epithelium migration could be seen along the dental implant and cell-rich fibrous connective tissue was observed. At day 7, new epithelial cells from basal cells of the oral epithelium had begun to migrate along the implant surface. By day 14, the epithelial cells had spread further apically facing the implant surface and were observed as aPIE. At day 28, a non-keratinized aPIE had formed consisting of a few cells in thickness and a cell-poor fibrous connective tissue was observed at the interface of the implant. Immunohistochemically, the cells of middle layers of the aPIE were positive for CK13. Laminin-5 was positively stained not only in the basal layer, but also in cells facing the implant surface at days 3 and 7. However, laminin-5 stained positive only in the basal layer of the oral epithelium at days 14 and 28. PGP9.5- and Von Willebrand Factor-positive cells were observed in the connective tissue under the oral epithelium but not near the aPIE. However, cells positive for both antigens had migrated further toward the implant surface each day up to day 28.
The aPIE, which is a non-keratinized epithelium, is initially attached to the implant surface but is subsequently released from the implant surface during wound healing of the connective tissue.
