tailieunhanh - Ebook Atlas of cosmetic and reconstructive periodontal surgery (3/E): Part 2

(BQ) Part 2 book “Atlas of cosmetic and reconstructive periodontal surgery” has contents: Visual perception, esthetic structural analysis, differential diagnosis of anterior tooth exposure, biologic width, peiodontal biotypes, crown lengthening, altered passive eruption, ridge augmentation, and other contents. | 11/16/06 9:08 PM Page 217 13 Visual Perception Perception Perception is the psychological response, organization, and interpretation of sensory stimuli (sight, smell, taste, touch, and hearing). It is culturally based and subjective, which gives rise to the truism “Beauty is in the eye of the beholder.” The comparison of stimuli with our previous experiences, which are then interpreted, is known as precept. Esthetics is derived from the Greek aesthesis, meaning perception. The science of visual perception or esthetics is the study of sensory stimuli and response. Visual perception is a prerequisite for esthetics, as is visual examination a requirement for clinical investigation (Rufenacht, 1990). Understanding the fundamental objective criteria of esthetics is a basic requirement for understanding and appreciating beauty. Composition Composition is the study of the relationship between objects made visible by contrasts in color, line, or texture (Figure 13-1). Contrast allows our eyes to “see” or differentiate. As contrast increases, so does visibility if there is enough light to illuminate. In dentistry, we are concerned with facial, dentofacial, and dentogingival compositions (Lombard, 1973). Unity The prime requisite of composition is unity (Lombard, 1973). Unity is the ordering of differ- FIGURE 13-2. The individual element is different when made part of the whole. FIGURE 13-1. Objects made visible by contrast. ent individual parts of the composition to give the effect of the whole. The whole is greater than the sum of the individual parts and is now a new entity, as a musical note is to a sheet of music or an individual tooth is to a segment of teeth (Figure 13-2). Unity may be subdivided into stagnant and dynamic unity (Rufenacht, 1990): Stagnant unity (Figure 13-3) 1. 2. 3. 4. 5. Geometric shapes Nonliving Inert (no motion) Repetitions Examples: crystals, snowflakes, water droplets FIGURE 13-3. Stagnant unity is nonliving, inert