The principles of visual perception and their clinical application to denture esthetics

Authors: Richard E. Lombardi, D.D.S. Seattle, Wash.

Complete dentures, this article was cited by Digital Smile Design

When the term “esthetic” or “unesthetic” is used, the connotation is that something is seen which is pleasant or unpleasant. This complex process is not merely a rod and cone function. The visual stimuli pass to the center of vision in the brain where the physiologic stimuli can engender a pleasant or unpleasant psychologic response. Whether the viewer’s perception of a visual experience is pleasant or unpleasant may be conditioned to some extent by cultural factors, and what is considered “beautiful” in one culture may be “ugly” in another. For example, the practice of filing the teeth to sharp points as practiced in some primitive cultures is considered beautiful only in those specific cultures. Basically, however, the viewer’s response is a psychologic response resulting from the interpretation of physiologic processes. This stimulus and response constitutes the science of visual perception. Over the centuries, as artists have developed the management of these processes into principles of visual perception, they have been enabled to create scenes of intense vitality, beauty, depth, and realism, all on a two-dimensional canvas. Today, scientific investigations into the physiology and psychology of seeing confirm the validity of these earlier intuitive developments.

These investigations have resulted in the formulation and verification of a set of laws or “principles” of visual perception. It is the purpose of this article to discuss these principles and suggest their application to denture esthetics. The denture is subject to the same perceptual processes as anything else that is perceived. An understanding of perceptual principles can eliminate confusion in the realm of esthetics. Many different types of denture teeth and systems for their placement are in use today. Some of these definitely produce a better esthetic result. The reasons why this is true lie in the realm of the visual perceptive principles.

The need for a simplified approach to esthetics is enormous. Half of the citizens of the United States over 55 have lost their natural teeth. An average of 90 per cent of inductees into military service require dentures. 1 Medical science is constantly increasing the human life span and there are more insurance plans with dental coverage. Dentists who understand the principles of perception can free themselves from conflicting and confusing dental rules, and approach the construction of dentures with confidence that they will be esthetically pleasing.

The sins in the field of denture esthetics are of two types : ( 1 ) the sin against the principles of visual perception and (2) the sin against the principles of reality. The principles of visual perception should not be applied with such exuberance that a sin against reality results. These principles must be used with all the subtlety and wisdom required in the application of any natural law.


We “see” only because the eye differentiates. It can differentiate only if contrasts exist in the situation being viewed. As the amount of contrast increases, visibility increases. As the amount of contrast decreases, visibility decreases. Nature’s protective coloration of some animals and birds demonstrates this phenomenon. We are enabled to “see” because of contrasts in color, line, and texture and, of coupe, enough light must be present to illuminate the contrasts. All of these factors are under the control of the dentist making dentures of beauty that will brighten a long darkened smile.

The study of the relationships existing between objects made visible by the contrasts in color, line, and texture is called composition.

Unity. The prime requisite of composition is unity. Unity means “one-ness.” Unity is the ordering of the parts of a composition to give the individual total effect of the “whole.” The whole is new entity–greater than the sum of its parts, just as a melody is a separate, greater, new entity than a collection of the notes of which it is composed. Unity exists in two types, static unity and dynamic unity. “Static unity is exhibited by such structures as regular geometric shapes. Natural inorganic forms such as snowflakes and crystals are examples of static unity. Plants and animals are dynamic unities. The former are passive and inert; the latter active, living, and growing. The static structures are fixed and without motion; the dynamic are a crescendo approaching a climax.

“Static designs are based on a regular repetitive pattern and on the uniform unchanging curve of the circle, whereas the dynamic are like the flowing continuity of the logarithmic spiral with its generating nucleus. ”

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