Impact of EMD-coated implant surfaces on epithelial-cell adhesion and proliferation

Objectives: The quality of the epithelial and connective tissue attachment around dental implants is of particular importance to ensure long-term tissue integrity. As enamel matrix derivatives (EMD, Straumann®, Sweden) are known to play a major role in periodontal regeneration, the purpose of this in-vitro study was to determine the impact of EMD coated implant surfaces (Straumann®, Switzerland) on soft tissue healing.

Methods: Human epithelial cells (SCC25, ATCC) were grown on five modified titanium surfaces (MA: machined; A: hydrophobic acid-etched; modA: hydrophilic acid-etched; SLA: hydrophobic coarse-grit-blasted, acid-etched; modSLA: hydrophilic coarse-grit-blasted, acid-etched) with or without EMD-coating (100µg/ml) for 72h, 7d and 10d for proliferation assays. Cell morphology was visualized (24h) using immunofluorescence microscopy staining against actin (Phalloidin, Molecular Probes®). Adhesion (3h) and proliferation rates were measured fluorometrically (CyQuant, Quiagen®). Student t-test was used for statistical analysis.

Results: SCC25 showed differences in morphology, adhesion and proliferation rates depending on the examined titanium surface, EMD-coating and time point of observation. Microscopy revealed that SCC25 cultured on MA surfaces were mainly of round or cuboid shape, whereas epithelial cells on other surfaces had less sharply delineated cell edges.

Adhesion and proliferation was generally superior on MA surfaces than on any other surface. In group comparison coating with EMD significantly increased (p < 0.05) the adhesion rate compared to uncoated controls. EMD-coating inhibited proliferation at 72h (p < 0.05) compared to uncoated controls, whereas after longer proliferation periods (7d and 10d) this effect was not significant between coated and uncoated titanium surfaces.

Conclusions: Our preliminary data support the idea that EMD initially promotes cell adhesion but inhibits epithelial cell growth and may therefore favour connective tissue attachment around dental titanium implants. Supported by LMU FÖFOLE-Grant Nr. 514