Aim: The aim of this study is to investigate the impact of various amelogenin preparations on the attachment and proliferation of periodontal ligament cells (PDL-cells) on periodontally infected root surfaces. Material & Methods: Root surfaces of periodontally infected, extracted human teeth were treated with scaling and root planing (SRP) and subsequently coated with three different amelogenin preparations, the clinically well-established Emdogain, a recombinant human wildtype-amelogenin (rH174), and a modified recombinant human wildtype-amelogenin (RGD-amelogenin). For modification, the tripeptide Arg-Gly-Asp (RGD) loop from fibronectin was inserted into the rH174 nucleotide sequence at the C-terminal ending using polymerase chain reaction (Imhof et al., 2015). PDL-cell attachment was measured after 30 minutes. PDL-cell proliferation on coated periodontally infected root surfaces which were treated with SRP was analysed after 72 h and compared with healthy root surfaces (positive control), periodontally infected, untreated root surfaces (negative control) or root surfaces that were exclusively treated with SRP. Cell morphology and distribution was documented using a scanning electron microscope. Results: The attachment analysis revealed a significant increase in PDL-cell attachment after coating with Emdogain compared to coating with wildtype-amelogenin (p0.05). RGD-amelogenin caused an even higher increase compared to Emdogain (p0.05). SRP and wildtype-amelogenin caused a significant increase in proliferation compared to the negative control (p0.05). Emdogain and RGD-amelogenin led to an even higher increase in proliferation compared to SRP and wildtype-amelogenin. None of the groups was able to reach the level of proliferation of the positive control (p0.05). Conclusion: The applied, simulated clinical conditions result in outcomes for Emdogain that are in accordance with those of recent clinical trials. This supports the chosen methods. For the first time, the positive effect of RGD-amelogenin on PDL-cell adhesion and on PDL-cell proliferation compared with Emdogain were shown. Obviously, the higher number of cells after 72 hours on root surfaces coated with RGD-amelogenin is caused by the optimised initial cell adhesion. Emdogain, however, possibly contains more components, besides amelogenins, which stimulate cell proliferation. The combination of RGD-amelogenin and Emdogain could be an option for optimising periodontal regeneration. This must be confirmed clinically. Keywords: PDL-cell, attachment, proliferation, periodontal regeneration, Emdogain, amelogenin, fibronectin, RGD