Microscopy surface structural aspects

The corrugation, i.e., the roughness of the surface, whether the surface has anomalities or not, can locally change the reactivity at a given surface site. STM (scanning tunneling microscopy) has revealed new information on the surface structure at the atomic level [1], and since the surface structure can be important for the molecular processes it is of course desirable also to be able to model this aspect theoretically. Thus the influence of surface defects, dislocations, and other unusual structure on catalytic rates is an important issue. 

This review covers the formation, composition, structure, function and properties of the acquired pellicle. Specifically, the formation of pellicle is considered in terms of thermodynamic and kinetic aspects. The composition of the pellicle is reviewed in terms of the proteins, carbohydrates and lipids that have been identified using a range of analytical techniques. The ultrastructure of the pellicle is described in some detail from studies involving enamel slabs carried in the mouth, in which the subsequent pellicle was analysed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The function of the pellicle is outlined in terms of its lubrication properties, its ability to act as a semi-permeable membrane and its overall protection of the underlying enamel surfaces. Since pellicle is formed at the interface between the enamel surface and the oral environment, the important process of bacterial attachment to the pellicle surface is described and the specific bacterial binding sites found in the pellicle are summarised. The influence of diet and nutrition on the pellicle layer is considered. The formation of extrinsic stain is discussed in particular, the role that chlorhexidine... 

---