Stippling is the creation of a pattern simulating varying degrees of solidity or shading by using small dots. Such a pattern may occur in nature and these effects are frequently emulated by artists.
In a drawing or painting, the dots are made of pigment of a single colour, applied with a pen or brush; the denser the dots, the darker the apparent shade—or lighter, if the pigment is lighter than the surface. This is similar to—but distinct from—pointillism, which uses dots of different colours to simulate blended colours.
In printmaking, dots may be carved out of a surface to which ink will be applied, to produce either a greater or lesser density of ink depending on the printing technique. In engraving, the technique was invented by Giulio Campagnola in about 1510. Stippling may also be used in engraving or sculpting an object even when there is no ink or paint involved, either to change the texture of the object, or to produce the appearance of light or dark shading depending on the reflective properties of the surface: for instance, stipple engraving on glass produces areas that appear brighter than the surrounding glass.
The gingiva often possess a textured surface that is referred to as being stippled (engraved points). Stippling only presents on the attached gingiva bound to underlying alveolar bone, not the freely moveable alveolar mucosa. Stippling used to be thought to indicate health, but it has since been shown that smooth gingiva is not an indication of disease, unless it is smooth due to a loss of previously existing stippling.
Stippling is a consequence of the microscopic elevations and depressions of the surface of the gingival tissue due to the connective tissue projections within the tissue. "The degree of keratinization and the prominence of stippling appear to be related." To be more specific, stippling occurs at sites of fusion of the epithelial ridges (also known as rete pegs) and correspond to the fusion of the valleys created by the connective tissue papillae.