![]() The effect is usually created with highly colour saturated porcelain powders and manufacturers supply these separately. Gingival effects are a most useful way for the ceramist to lap in colour at the cervical third of a restoration prior to the main porcelain build-up. 6-1a and b (a) Diagram of the various types of stain, concentrated colours and porcelains used to create special effects in a veneer crown. A typical selection of glazed pigment stains is shown in Figure 6-1b.įig. Stain which occurs naturally on teeth produced by tobacco, food, beverages, caries or other causes. Defects in calcification, cracks, structural defects, internal staining. Variations in the anatomy of the dentine core and thickness of overlaying enamel. Faults in calcification or structural defects. Neck or gingival effects simulating root dentine.The intensity of colour is controlled by dilution with uncoloured glass powder to form a concentrated colour or in the case of a stain the fritted powder may be used in its pure state. “Special Effects” in dental porcelain are created with the use of supplementary colours of the basic dentine porcelain, translucent or colourless porcelain and concentrated colours made from the basic porcelain frit, into which metallic oxide pigments are fritted. The root and cervical areas of the crown deserve special attention if they are to blend harmoniously with the gingival tissue. Porcelain colours must be built in depth and surface colourants applied judiciously in areas where natural staining occurs in the mouth. In order to duplicate a natural tooth, the structural defects, degrees of calcification and varying thicknesses in enamel should be duplicated in the porcelain build-up. If a crown is made with a body dentine and standard incisal overlay it will generally look very artificial in the mouth except in the very young patient. When making porcelain crowns the ceramist is supplied with basic dentine and enamel porcelains with which to create the form and colour in the crown. Human teeth vary considerably in texture, colour and form. Natural teeth lie, therefore, in a very narrow band of colour, and this explains why matching shades in teeth is so difficult (Monograph III, McLean, 1979). This property is related to brightness or lightness.Ĭlark (1933) in a study measuring natural tooth colours on the Munsell scale, showed a scattering of tooth shades predominantly in a small part of the light yellow area, relatively fewer in the band above, and no occurrence over more than 99 percent of the Munsell range. The strength or purity of a colour at any given Value level. Colour may be divided into three main components:
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