Formulation of enamel matrix derivative for surface coating. Kinetics and cell colonization.

Enamel Matrix Derivative (EMD) contains a protein complex belonging to the amelogenin family. Enamel matrix as well as EMD have been found to promote periodontal regeneration when applied onto denuded root surfaces in dehiscence models. In the present studies it is shown that propylene glycol alginate (PGA) is a suitable vehicle for EMD for its local application. EMD can be dissolved in PGA at an acidic pH, resulting in a highly viscous solution. At neutral pH and body temperature the viscosity decreases and EMD precipitates. Multilayers of EMD on mineral or protein surfaces have been analysed using ellipsometry, total internal reflection fluorescence (TIRF) and biospecific interaction analysis (BIA). The studies show that EMD adsorbs both to hydroxyapatite and collagen and to denuded dental roots. It forms insoluble spherical complexes, and detectable amounts remain at the site of application on the root surface for two weeks, as shown with radiolabelled protein in rats and pigs. Scanning electron micrograph (SEM) studies on monkey teeth further indicate that EMD in PGA may promote repopulation of fibroblast-like cells during the first weeks after application.