Nowadays there is great importance on the external appearance of each one, being the appearance of the teeth one of the key pillars in the aspect of the smile. The shape, color and size of the teeth are some of the important factors.
What is the color?
Color is a subjective perception of light rays after reflecting objects at a certain wavelength. It is for this reason that there may be variability of opinion of colors among various subjects. In addition, for there to be color it is essential that there is light. The wavelength that is perceived by human eyes is between 380 and 760 nanometers. Thus, the color variation depends on the energy absorbed. It is known that to make a correct measurement of chroma, a light source with a temperature between 5000ºK and 65000ºK must be had, since different temperatures can vary the perception of the tooth. The dimensions of the color are several: hue or hue, saturation and brightness or brightness. The hue is the degree of mixing between the primary colors, these are three: green, blue and red, depending on the amount of hue and the mixture between the primary colors you can see the other colors. Saturation is the amount or degree of purity of the nuances. The brightness is the amount of light in an object, so the scale varies from white to black, through grays.
During the incidence of light on an object it can interact in several ways: reflecting, refracting, absorbing or dispersing. Reflection occurs in most bodies. It depends on the teeth if the surface is polished or not, if it is smooth there is a great reflection of light. Refraction is the change of direction of light. In the tooth, depending on the layer (enamel, dentin or pulp) the light is refracted differently. The absorption in the teeth can be combined with the reflection between the enamel and the dentine. The diffusion of light in the teeth makes their anatomy perceived. The optical phenomena that can occur are translucency or opacity, opalescence, fluorescence and metamerism. Translucency is the complete passage of light, while opacity is blocking it. Opalescence is the simultaneous production of refraction, diffusion and interference, so that bright and vivid colorations are emitted. Fluorescence is the ability of an object to absorb light emitting it with less energy. Finally, metamerism is the effect that when different objects with the same color change color. The different thicknesses of the layers of the tooth, the enamel, the dentin and the pulp, make the tooth have the characteristic color and that this can vary throughout the life of the patient. Importantly, the color of each layer is directly influenced by the amount of organic and inorganic tissue it has.
How can dental color be measured?
In order to measure the color of the teeth or each part of the tooth, it is essential to know a good measurement technique and use techniques to perform it. The subjective method of color measurement is the color guides. These are resin tablets in the form of an incisor with various colors. The VITA guide is one of the most used in dentistry, which is ordered according to saturation / hue. This is based on 4 shades: A, B, C and D. The A has a more orange-reddish color, the orange-yellow B, the brown-gray C and the D that is brown. In hue A there are 5 levels of chroma, where A1 is the least saturated brown and A4 the most.
To be able to take the color with objective methods, there are nowadays systems that supply and reproduce data exactly. These are electronic instruments to facilitate the taking of color in a reliable, accurate and repeatable way for different professionals. There are several devices some of them are colorimeters, spectrophotometers, digital color analyzers and hybrid instruments, which combine all technologies. Colorimeters are objectively measuring instruments of color which have a light source and a small tip to make it possible to take color in several areas of the same tooth. pectrophotometers are the instruments that currently have more precision in color taking. These measure the color by emitting a defined light. In addition, they have the ability to measure the reflection of a color by translating it to numerical values, which are interpreted.
