**5.2 Conditioning films forming on the substratum**

When a material surface gets exposed to any aqueous medium, it gets immediately coated with polymers from that surface or become conditioned. The coating or film is found to be organic in nature formed within minutes of exposure. The nature of these films is found to be quite different for surfaces exposed in the human host. As an example, "acquired pellicle," a proteinaceous conditioning film, develops on tooth enamel surface. A pellicle is composed of glycoprotein, lysozymes, phosphoproteins, albumin, lipids and gingival crevice fluid. Oral cavity bacteria get adhered within hours of exposure to this pellicle conditioned surface.
