PEG is a water-swellable, non-toxic, and biocompatible polymer. Its use in biotechnology has been reported in the literature . Polymer brushes consisting of PEG opened a wide door in biomaterials research due to the suitable properties of the polymer . Polymer brushes are linear polymer chains terminally anchored to solid surfaces. If the distance between the anchoring points of the surface-grafted chains is small, interchain correlations occur. The tethered chains are stretched away from the surface leading to a “brush”-like conformation. Such polymeric monolayers play an important role in a wide range of colloid stabilization, tribology, lubrication, and rheology . PEG-modified surfaces have a high degree of hydration. The modified surfaces are effective in reducing diatom adhesion and weakening protein adsorption . This study showed that the tooth surface became more hydrophilic after coating it with polydopamine-induced-PEG. The resistance to adhesion of protein and bacteria to the PEG-modified surface can be attributed to the large exclusion volume, high mobility, and steric hindrance effects of this hydrophilic layer (Figure 6) .