Cell Adhesion to Biomaterials: Concept of Biocompatibility - Advances in Biomaterials Science and Biomedical Applications - page 217

2.5. Conclusion

When a drop of liquid is placed on a solid surface, the liquid will either spread across
the surface to form a thin, approximately uniform film or spread to a limited extent but
remain as a discrete drop on the surface. The final condition of the applied liquid to the
surface is taken as an indication of the wettability of the surface by the liquid or the wet‐
ting ability of the liquid on the surface. The quantitative measure of the wetting process
is taken to be the contact angle, which the drop makes with the solid as measured
through the liquid in question.

The wetting of a surface by a liquid and the ultimate extent of spreading of that liquid
are very important aspects of practical surface chemistry. Many of the phenomenological
aspects of the wetting processes have been recognized and quantified since early in the
history of observation of such processes. However, the microscopic details of what is oc‐
curring at the various interfaces and lines of contact among phases has been more a sub‐
ject of conjecture and theory than of known facts until the latter part of this century
when quantum electrodynamics and elegant analytical procedures began to provide a
great deal of new insight into events at the molecular level. Even with all the new infor‐
mation of the last 20 years, however, there still remains a great deal to learn about the
mechanisms of movement of a liquid across a surface.

3. Fibroblast cells

3.1. Human gingival fibroblasts

3.1.1. Generality

Fibroblasts are spindle-shaped connective-tissue cells of mesenchymal origin that secretes
proteins and especially molecular collagen from which the extracellular fibrillar matrix of
connective tissue forms. They have oval or circular nucleus and a little developed cyto‐
plasm giving rise to long prolongation forms [34]. These cells do not have a basal lamina
and their surfaces are often in contact with the fibers of the collagen. Their cytoplasm
contains a rough endoplasmic reticulum, an important Golgi apparatus, few mitochon‐
dria and a little bit quantity of cytoplasmic filaments. Fibroblasts synthesize enormous
quantities of the extracellular matrix constituents. Indeed, the majority part of the extrac‐
ellular matrix components consists of collagen made in the intracellular space where fi‐
broblasts sustain structural modifications.

3.1.2. Gingival tissue

It's the tissue that surrounds the necks of teeth and covers the alveolar parts of the jaws;
broadly: the alveolar portion of a jaw with its enveloping soft tissues [35]. It consists in a
pink connective tissue with fibrous collagen surrounded by an epithelial tissue. Its pink col‐
or changes from one person to another, depending on pigmentation, epithelium thickness,
its keratinization level and on the underlying vascularization [36]. Fibroblasts are the basic