Dental shade system

Abstract: A dental shade system that includes one or plural triangle pillars on three faces of which many different color samples are arranged and by which the natural tooth color can be compared with the color samples with one or two actions and decided by the sense of sight in terms of three coordinates in color space, in order of Value (lightness), Chroma (color saturation), and Hue (color).

Description: 1. Field of the Invention The present invention relates to a dental shade system for measuring natural tooth color, by classifying natural tooth colors in terms of three dimensional coordinates of Value, Chroma, and Hue and by arranging dental color samples (shades) equidistantly in the sense of sight. 2. Description of the Conventional Art Dental shade system (in other words, dental shade guides) is the dental system composed of color samples necessary to meet patient's satisfaction by matching the color of dental prostheses including artificial teeth to the patient' s natural tooth color, improving prostheses esthetically. In the process of fabricating dental prostheses, information of the patient's tooth color is required to be included in the instructions written in a prescription card sent from the dentist to the laboratory technician. Therefore, in a dental clinic, it is indispensable to select color which matches patient's natural tooth color and send its information to the laboratory. As the patient's interest in dental esthetics has increased, the importance of its precise information has rapidly increased. As is generally known, the colors that human eyes sense are described by three dimensional coordinates; Value (lightness level), Chroma (color saturation), and Hue (color). These coordinates have been well known as the Munsell system (Munsell, 1905), by the reason that its color samples are arranged with perceptuallyeven spacing. However, with the development of color science, the existence of the inherent chromatic distortions in the color space of the Munsell systembecame clarified. Spacing the color samples requires a non distorting color space such as the more recently developed and internationally accepted colorimetric for reflective materials, CIELAB (CIE 1978). However, conventional dental shade guides have not been arranged logically or scientifically and do not even correspond to measured tooth color. Shade guides of all dental restorative materials are based on the long established porcelain shade guides which evolved to represent the available shades of porcelain teeth. The shades developed by a process of popular selection by which shades perceived to be nearer tooth color were added and the least popular eliminated. This concept has not changed since the introduction of porcelain over two hundred years ago. The tooth color is limited from yellowish to reddish and occupies about 1 % region of total color space. Moreover, existing dental shade guides have contained only 6∼12 % among the 1 % region of the total color space mentioned above. In addition, since these dental shade guides have been selected by experience, the distribution of its colors in color space has not been uniform. Accordingly, the result of its use has been incorrect and not effective, so it has been difficult to match the color of prostheses to patient's natural tooth color in the sense of sight. To resolve this problem, in recent years, a dental shade system applying color science was developed by Hall, evaluating existing methods and problems and quantifying the difficulties of color matching. A tooth color order system is developed. resulting in the construction of a tooth color atlas assembled for easy use offering the accurate measurement of tooth color and the potential of perfect color matching (Hall 1991 and U.S. Pat. No. 5,498,157). In the dental shade system developed by Hall, the color samples are arranged like lattice in color space at equal interval which is near the threshold value of the ability of human sight distinguishing colors. They are consisted of Values of 5 steps (marked as 1, 2, 3, 4, and 5 in order of lightness), Chromas of 3 steps (marked as 1, 2, and 3, in order of weak, medium, and strong clearness), and Hues of 3 steps (marked as L, M, and R in order of yellowish, medium, and reddish), totaling 5x3x3=45 color samples as the basic composition of the system. By this composition, first scientifically reasonable dental shade system which covers the total region of the color distribution of human natural tooth in color space has been actualized. In Table 1, the basic composition of the color sample arrangement of Hall dental shade system 111 is shown. In the basic composition of the color sample arrangement of Hall dental shade system shown in Table 1, the colors of each color sample is marked according to Hall's notation. For example, 3M/2 means that the Value of the color sample is 3, the Chroma is 2, and the Hue is M. The occurrence rate of tooth color in color space is not uniform. When we marked Values of 5 steps as V1. V2, V3, V4, and V5 in order of lightness (corresponding to 1, 2, 3, 4, and 5 mentioned above), the occurrence rate of V1 is 2 %, V2's is 26%, V3's is 50%, V4's is 20%, and V5 's is 2%, differing largely with each other. Since the similar situation exists for the case combining Chroma and Hue, it can not be said the best, in view of cost versus effect ratio, to compose a dental shade system with many color samples paying attention only to the region of color space where tooth color occupies. By such a practical reason, Hall reduced the number of color samples from 45 mentioned above to 26, by excluding the color samples the occurrence rates of which are low. As the result, as shown in Fig. 5, Hall dental shade system 111 is constituted of 11 bundles which are inserted into the color sample rack 114 arranged horizontally and on each bundle two or three color samples 113 are attached in order and a handle 112 is attached at the bottom. In Table 2, the practical composition of the color sample arrangement of the Hall dental shade system 111 is shown. In Table 2, x marks show 7 among 19 color samples which are excluded due to their low occurrence rates. (The other 12 color samples in rows 1L, 1R, 5L, 5R which are excluded due to their low occurrence rates, are omitted from Table 2). In relation to the order for selecting in the sense of sight the color sample the color of which matches the natural tooth color among the color samples of the dental shade system 111, Hall recommends to select it in the order of Value, Chroma, and Hue. In the practical composition of Hall dental shade system 111 shown in Table 2, the reason for that the color samples 113 having weak Chroma (1 or 1.5) are arranged in the first line 115 (front line 115 in Fig. 5: upper side in the figure) is, that if the color samples had strong Chroma, it is difficult to decide the Value of the natural tooth by approaching the color sample rack 114 to the patient's natural tooth. In addition, as shown in Fig. 5, the tops of the color samples having medium Hue (M) among the color samples arranged in the first line 1 15 are projected slightly more above (in Fig. 5) than the tops of the neighboring color samples in the first line 115 so that the sense of sight is not disturbed by the neighboring color samples having yellowish Hue (L) or reddish Hue (R) . Moreover, in the practical composition of the Hall dental shade system 111 shown in Table 2, some of Chromas 1 or 3 are replaced by 1.5 or 2.5 where latter marks (1.5 and 2.5) indicate intermediate Chromas, respectively. The reason for the above replacements is to revise non-uniformity of the distance in color space between residual color samples which has resulted from having color samples with low occurrence rates excluded, as mentioned above. As described heretofore, the method to decide the color in terms of Value, Chroma, and Hue by means of comparing the color samples with the object in the sense of sight, is a classical one known together with the name of Munsell system. However, the method of this type is, even in the present days, said to be the most superior dental clinical method to modern colorimetrics utilizing electronics, by the reason that the method is extremely low cost, does not need a standard light source or a dark room, and can perform colorimetry in the sense of sight with high sensitivity. PROBLEMS TO BE RESOLVED BY THE PRESENT INVENTION According to recent clinical experiences, it becomes clear that Hall dental shade system 111 shown in Fig. 5 and described above includes, notwithstanding its highly reasonable composition of color samples applying color science, drawbacks in view of the convenience on its handling as follows. As described above and shown in Fig. 5 and Table 2, Hall dental shade system 111 is composed of 26 color samples 113, making 2 or 3 of the color samples which are same in Value and Hue but different in Chroma each other into a bundle, constituting totally 11 bundles arranged horizontally on a color sample rack 114. At the time of selecting the color sample which matches the natural tooth color, using the dental shade system 111 constituted as described above, following procedure is recommended. In the first step, select the color sample which matches the natural tooth color in Value, among the color samples of 5 steps in Value which are arranged on the front line 115 and having weak Chroma (1) and medium Hue (M). In the second step, select the color sample which matches the natural tooth color in Chroma among the color samples of 2 or 3 steps in Chroma arranged on the same bundle with said color sample selected in the first step. In the third step, select the color sample which matches the natural tooth color in Hue, among three color samples composed of said color sample selected in the second step and the two color samples arranged on both sides of said color sample. While following this procedure, using the color samples of Hall dental shade system 111 arranged on the color sample rack 114 shown in Fig. 5, there are problems in view of the convenience on handling as follows. Firstly, for selecting the color sample which matches the natural tooth color in Value, it is necessary to begin with selecting two neighboring color samples having medium Hue (M) from among 11 color samples arranged in order of Value of 5 steps on the front line 115 of the color sample rack 114. And in order to decide which color of said neighboring color samples is closer to the natural tooth color in Value, the color sample rack 114 of the dental shade system 111 as shown in Figure 5 must be approached to the patient's mouth. At that time, since all of the 26 color samples 113 enter into the field of view at one. time, it is extremely difficult in the sense of sight to decide which of said two neighboring color samples matches the natural tooth color in Value. More specifically, the color samples arranged on both sides of each of said two color samples having medium Hue are disturbing because they have different Hues (L or R). To avoid the difficulty mentioned above, it may be a choice first to pull out the two bundles on which the two color samples to be compared in Value are arranged and then to compare them by approaching the color sample on the top of each bundle to the patient's mouth, repeatedly. However, that cannot be an efficient method in clinical situation. Secondly, for selecting the color sample which matches the natural tooth color in Chroma among the color samples on the bundle having the Value selected, it is necessary to begin with pulling said bundle out of the color sample rack 114 of the dental shade system 111 shown in Figure 5, and then to approach it to the patient's mouth, because three color samples having same Value and different Chroma are arranged in the longitudinal direction of the bundle. However, if the color sample on the top of the bundle is approached to the natural tooth to be compared, the other two color samples are in distant position from the natural tooth, so it is difficult to compare the three color samples in equal distance from the natural tooth. To avoid the difficulty, only choice is to turn sideways the bundle of color samples, and to approach the three color samples to the natural tooth so that they are in same distance from the natural tooth, resulting in inconvenience that the color sample resembled in shape to the natural tooth is turned sideways. In this connection, although each of the three color samples can be rotated by 90 degrees around the fulcrum of the support plate so that they can be compared with the natural tooth in same distance and in same situation with each other, but to handle such manipulations one by one takes time and is not efficient. Thirdly, for selecting the color sample which matches the natural tooth color in Hue among the color samples having the Value and Chroma selected, it is necessary to begin with pulling the bundle of the color sample (having medium Hue (M)) together with the bundles having yellowish Hue (L) and reddish Hue (R) on both sides of said bundle out of the color sample rack 114 of the dental shade system 111 shown in Fig. 5, and to approach it to the natural tooth to be compared. In this case, to compare color samples with the natural tooth color, holding the three bundles of color samples by hand and keeping each color sample of the three bundles in same distance and in same situation with each other is more troublesome than described above, and it is entirely inadequate in clinical situation. As mentioned above, at the time of comparing color samples and the natural tooth color, it is necessary to match the longitudinal directions and the situation of the top and the bottom of the both. However, in the conventional dental shade system 111, although the shape of the color samples is imitated to the natural anterior tooth, the color samples are stationed matching the situation of the top and the bottom with the maxillary anterior tooth. Accordingly, the situation of the top and the bottom of the color sample rack 114 or the bundle of color sample 112 must be reversed to compare with the mandibular anterior tooth, resulting in extreme inconvenience. Therefore, although the composition of the color sample arrangement of conventional dental shade system has reasonability applying color science, the handling method for comparing the color samples with the natural tooth color has not been simple. Moreover, since the color sample arrangement of the dental shade system 111 lacks clearness, user cannot perceive intuitively the three-dimensional character of color which man's eye sense. SUMMARY OF THE INVENTION The object of the present invention is to provide a dental shade system, in which the following problems has been solved to overcome the drawbacks of the conventional art described above. (1) The efficient method, not by inserting many bundles composed of two or three color samples into a color sample rack, but by arranging the color samples separately on one body or plural bodies, so as to enable user to compare patient's natural tooth color with the color samples in order of Value, Chroma, and Hue each by one or two actions, and if necessary, to reverse the situation of top and bottom of the color samples by one action. (2) The simple and clear comparison method, for comparing patient's natural tooth color with a couple of the color samples which differ in Value, Chroma, or Hue each other, in the situation that the other color samples do not enter into the field of vision except said couple of color samples to be compared, and that said couple of color samples and the natural tooth in the field of vision are placed at same distance each other, so as to enable user to compare and decide which of said couple of color samples matches the patient's natural tooth color in Value, Chroma and Hue. (3) The method, with use of which user can perceive intuitively that character of color which man's eye senses is represented by three dimensional coordinates composed of Value (lightness level), Chroma (color saturation), and Hue (color). In the present invention, there is provided a dental shade system, in which many color samples (shades) are arranged equidistantly (with equal step) in the sense of sight in color space in terms of three dimensional coordinates of Value, Chroma, and Hue, wherein, many different color samples are placed separately on one or plural narrow triangle pillars, those color samples which are different each in plural steps in Value or Hue are arranged in order or in combination in the longitudinal direction of said triangle pillar on each of the three faces of said triangle pillar and the color samples having different Chroma in 3 steps are arranged on each of the three faces of said triangle pillars, so that user can decide the three coordinates of tooth color which matches patient' s natural tooth color in Value, Chroma, and Hue. Therefore, in the present invention, not adopting the method of the color sample rack in the conventional art, but arranging many different color samples separately on one or plural narrow triangle pillars, and arranging the color samples which are different in plural steps each in Value or Hue in the longitudinal direction on each of the three faces of said triangle pillars in order or in combination, and further arranging on each of the three faces of said triangle pillars the color samples having different Chroma in 3 steps each, so that it is enabled to select the color sample which matches the patient' s natural tooth color, by approaching said triangle pillar to patient's mouth holding it horizontally by both hands and by moving it to left and right (in the longitudinal direction) for selecting the color sample which matches patient's natural tooth color in Value and Hue, and further by rotating said triangle pillar by 120 degrees front(clockwise) or back (counter- clockwise) for selecting the color sample which matches patient's natural tooth color in Chroma. As described above, in the conventional art, at the time of comparing the natural tooth color with the bundled color samples 113 arranged on the color sample rack 114, occasionally, the case happens that unnecessary color samples, sometimes all, enter into the field of vision, making difficult to distinguish the two color samples to be compared from among others in the sense of sight. Moreover, in the conventional art, there are several ways for comparing the patient's tooth color with color samples and deciding each of the three coordinates of the natural tooth color as follows. 1) The way to hold and approach all color samples to be compared to patient's mouth together with the color sample rack on which all color samples are arranged over broad planar area. 2) The way to pull out two or three bundles of color samples one by one out of the color sample rack, and hold and approach them to patient's mouth. 3) The way to hold sideways one bundle of color samples pulled out of the color sample rack and approach it to patient's mouth. 4) The way to rotate the color sample by 90 degrees around the axis of the narrow plate supporting the color sample to the bundle and approach it to patient's mouth. Therefore, to select one of the several ways as described above by trial and error in the conventional art, is complicated and troublesome. To the contrary, as described above in the summary of the present invention, the many different color samples are arranged separately on one or plural narrow triangle pillars, and the way to compare the patient's tooth color with color samples and decide the three coordinates of the natural tooth color, is only composed of picking up, holding, and approaching one of said triangle pillars by both hands to patient's mouth, and moving it left and right (in the longitudinal direction) or rotating it front or back by 120 degrees. Therefore, it is the remarkable point of difference in the present invention with the conventional art that the comparing method of tooth color is simple and efficient. Preferably, in Claim 2 of the present invention, all color samples may be arranged on one narrow triangle pillar. On the first face of said triangle pillar, the color samples having weak Chroma andmediumHue are stationed in order of Value, leaving spaces in the longitudinal direction. On both sides of each said color sample, the color samples having the same Value and Chroma with each said color sample and having more yellowish Hue and more reddish Hue than each said color sample (having medium Hue) are stationed, respectively. And further, on the same position with each said color sample in the longitudinal direction, the color samples having the same Value and Hue with each said color sample, are stationed on the second and the third faces of said triangle pillar. And also, in the above, the color samples on the second face have medium Chroma and the ones on the third face have strong Chroma, respectively. In Claim 1 of the patent described above, there was no regularity in the arrangement of the color samples arranged on said one or plural triangle pillars. However, in the present invention, by arranging the color samples having weak Chroma and medium Hue in order of Value leaving spaces in the longitudinal direction on the first face of said triangle pillar, it is enabled to select the color sample which matches patient's natural tooth color in Value among the color samples which are arranged in order of Value on the first face of said triangle pillar, by moving saidpillar left and right (in the longitudinal direction) in front of patient's mouth. At that time, since it is difficult to compare Value between the color samples having strong Chroma as mentioned above, in this embodiment, the color samples in Value having weak Chroma are arranged on the first face, so that the selection of the color sample in Value become easier. Next, in this first embodiment, the color samples having medium Chroma and strong Chroma are arranged on the second and third faces of said triangle pillar, respectively, so that the color sample which matches patient's tooth color in Chroma can be selected by rotating said triangle pillar front and back by 120 degrees. Further, in this first embodiment, the color samples having yellowish Hue and reddish Hue are stationed on both sides of the color samples having selected Value and Chroma (having medium Hue), so that the color sample which matches the patient's tooth color in Hue can be selected by moving said triangle pillar left and right (in the longitudinal direction) easily. As described above, it is the remarkable point of difference in the first embodiment of the present invention in comparison with the summary of the present invention that there is added regularity in the arrangement of the color samples, so that it can be enabled to select the color sample which matches patient' s natural tooth color by deciding three coordinates of the natural tooth color in order of Value, Chroma, and Hue, regularly. Preferably, in Claim 5 of the present invention, as well as in Claim 2, all color samples may be arranged on one narrow triangle pillar. On the first face of said triangle pillar, the color samples having weak Chroma andmediumHue are stationed in order of Value leaving spaces in the longitudinal direction. On the same position with each said color sample on the first face in the longitudinal direction, the color samples having the same Value and Hue with each said color sample, are stationed on the second and the third faces of said triangle pillar. And also, in the above, the color samples on the second face have medium Chroma and the ones on the third face have strong Chroma, respectively. In addition, in Claim 5 of the present invention, on both sides of each said color sample, the color samples having more yellowish Hue and more reddish Hue than each said color sample (having medium Hue) are stationed. Together with that, a rotary mechanism by which each position of said color samples having yellowish Hue and reddish Hue can rotate by hand around the axis of said triangle pillar is added. In Claim 2 of the present invention described above, the color samples having weak Chroma and medium Hue in order of Value leaving spaces in the longitudinal direction are arranged on the first face of said triangle pillar, and the color samples having the same Value and Chroma with each said color sample and more yellowish Hue and more reddish Hue than each said color sample are stationed on both sides of each said color sample, respectively. However, in this arrangement, when user held said triangle pillar horizontally and approached its first face to patient's mouth for selecting the Value of the natural tooth color, the two color samples which have the same Chroma but different Hue lie and enter into the field of vision between the two color samples to be compared in Value, so that simple and clear comparison is disturbed. As described above, it is the remarkable point of difference in the present invention with Claim 2 that, on the first face of said triangle pillar, the color samples having different Hue do not lie between the color samples which are arranged in order of Value leaving spaces in the longitudinal direction, so that the sense of sight is not disturbed by the color samples having different Hue, resulting in that simple and clear decision of Value is enable. As described above, in the present invention, for making the decision of Value simple and clear, there are left spaces on both sides of the color samples having weak Chroma and medium Hue on the first face of said triangle pillar, without stationing any color sample in said spaces left on the first face of said triangle pillar. On the one hand, a rotary mechanism is added to rotate by hand each portion of said spaces left on the first face of said triangle pillar around its axis, for the case that the color sample having weak Chroma stationed on the first face of said triangle pillar is selected, so that it is enabled to compare said color sample having mediumHue with the color samples having yellowish Hue and reddish Hue. Moreover, on said both sides of the color samples on the second and the third faces of said triangle pillar, the color samples having yellowish Hue and reddish Hue are stationed, resulting in that non-uniformity in color space is produced due to the difference of Chroma between the faces. To compensate that, the medium Chroma (C2) of the color samples on said second face and the strong Chroma (C3) of the color samples on said third face are revised to the intermediate values (C1.5 and C2.5), respectively. Further, in this second embodiment, the addition of the rotary mechanism become necessary as described above, resulting in the additive merits that the number of the color samples are enabled to be decreased by excluding the color samples with low occurrence rate and also that the color samples having different Hues each other are enabled to compare in the same plane. On the one hand, in Claim 2 of the present invention, at the time of selecting Value, Chroma, and Hue in order, first selecting Value by moving said triangle pillar left and right (in the longitudinal direction), then after selecting Chroma by rotating said triangle pillar front and back by 120 degrees, finally selecting Hue by moving again said triangle pillar left and right (in the longitudinal direction) and conclude the selection. During the process, since the actions for selecting Value and Hue are similar, so that both are likely to be mixed up. Therefore, it is another remarkable point of difference in the second embodiment of the present invention with the first embodiment that user can perceive intuitively the three-dimensional character of color which man's eye sense through his experience, selecting Hue by said rotary mechanism the action of which is entirely different with the selecting actions for Value and Chroma as described above. Preferably, in Claim 8 of the present invention, many different color samples maybe arranged separately on four narrow triangle pillars, comprising: first triangle pillar, on the first face among the three faces of said first triangle pillar, the color samples having weak Chroma and medium Hue are arranged in order of Value without space in the longitudinal direction, and on the same position with each said color sample in the longitudinal direction, the color samples having the same Value and Hue with each said color sample and also having medium Chroma and strong Chroma, are stationed on the second and the third faces of said first triangle pillar. And also, in the above, the color sample having medium Chroma is stationed on the second face and the ones having strong Chroma is stationed on the third face, respectively. Second triangle pillar, on the first face among the three faces of said second triangle pillar, the color samples having the lightest Value (V2) among three steps of Value (V2, V3, V4) the occurrence rate of which are high as described above and also having weak Chroma are arranged in order of yellowish Hue, medium Hue, and reddish Hue in the longitudinal direction, and on the same position with each said color sample in the longitudinal direction, the color samples having the same Value and Hue with each said color sample and also having medium Chroma and strong Chroma, are stationed on the second and the third faces of said second triangle pillar. And also, in the above, the color samples having medium Chroma are stationed on the second face and the ones having strong Chroma are stationed on the third face, respectively. Third and fourth triangle pillars, the color samples on which are composed of the ones having the Values V3 and V4, respectively, replacing the Value V2 of the color samples arranged on said second triangle pillar, among the Values with high occurrence rate. Therefore, in the present invention, firstly, select the first face of said first triangle pillar the color samples on which have weak Chroma and are easily selected in Value, by moving said first triangle pillar left and right (in the longitudinal direction), and positioning it so that the natural tooth is located on the intermediate position of two neighboring color samples and in between the Values of them the Value of the natural tooth color is, then decide which Value of the two color samples is close to the Value of the natural tooth. Secondly, on the same position with the color sample selected in the longitudinal direction, rotating said first triangle pillar by 120 degrees front (clockwise) or back (counterclockwise), then decide Chroma which matches the natural tooth color. In this case, it is not possible to compare the color samples having different Chromas at the same time in a field of vision, but it is possible to compare them instantly by rotating said triangle pillar by hand as described above. In the present invention, in case that the Value selected is lower than Values of 3 steps (V2. V3, V4), the occurrence rate of which are low (they are, V1, V5, etc.), finalize the selection work here, and making the color sample having Value and Chroma selected on said first triangle pillar as the color sample of the final selection. In this selection, the Hue of the color sample selected is medium, but since the occurrence rate of the color selected is low, this selection is sufficient in view of color science. On the other hand, in case that the Value selected is one of V2, V3 or V4 occurrence rate of which is high, hold said second (V2), third (V3), or fourth (V4) triangle pillar, rotating said (second, third, or fourth) triangle pillar front or back by 120 degrees, select the face having Chroma selected above on said first triangle pillar, moving said (second, third, or fourth) triangle pillar left and right, then select the color sample having Hue which matches with the natural tooth color as a final selection. Thus, user could finalize the decision of the three coordinates of patient's natural tooth color in order of Value, Chroma, and Hue, resulting in that the decision making of the three coordinates of natural tooth color is simple and clear and does not need any trial and error in each step of the above process in this third embodiment in the present invention. On the one hand, in Claim 5 of the present invention, selection work is finalized by first taking up said triangle pillar composed of one body and next moving it left and right in the longitudinal direction and last rotating said triangle pillar (or said rotary portion) front and back by 120 degrees. Against it, in the present invention, since selection work is finalized by first taking up said first triangle pillar and selecting Value and Chroma, next taking up one of said second, third, or fourth triangle pillar depending on the Value selected, and then selecting Hue, so that it seems to be composed of two taking up actions and more complicated than in the first (or second) embodiment. However, in Claim 3 of the present invention, in place of one body composition, the number of the color samples to be stationed in the longitudinal direction of said one body (triangle pillar) long. On the contrary, in this third embodiment, since the number of the color example is few, the total lengths of said first to fourth triangle pillars becomes 1/2 - 1/4 of the former. Therefore, in contrast with that holding said triangle pillar by both hands is necessary in the former, holding it by one hand is sufficient in the latter, so that for taking up said triangle pillar each, twice actions are necessary for the former (the first (or second) embodiment) than the latter (the third embodiment), resulting in compensation of the difference between the both in number of actions described above. It is needles to say that, in comparison between the conventional art or Claim 2 and the present invention, the difference between the both becomes more remarkable. In addition to the above, in Claim 5 of the present invention, since trial and error is necessary in every decision stage of Value, Chroma, and Hue, specifically in the stage of comparing Hue, practically, the number of action of ten exceeds two. However, in the present invention, since trial and error is hardly needed as described above, in almost every decision stage of Value, Chroma, and Hue, the number of actions is sufficient with one or two, including the actions which are to take up one of said first -fourth triangle pillars and approach it to patient' s mouth and to move said triangle pillar left and right or to rotate it (or said rotary portion) front and back by 120 degrees. This is the first remarkable point of difference in the present invention in the present invention in comparison with the conventional art or Claim 5. Further, although the shape of the color samples of the dental shade system in the prior art is imitated to the shape of the natural anterior tooth, the color samples are stationed matching the situation of the top and the bottom with the maxillary anterior tooth as described above, so that the situation of the top and the bottom of the color samples must be reversed to compare the color samples with the mandibular anterior tooth. In this case, in the prior art, the actions to pass the color sample or the plural bundles of the color samples held by both hands conversely are needed. The actions are not only complicated, but even if passing them conversely, the rack of the color sample rack or the handle of the bundle is in the way, causing to compare the natural tooth color with the color samples extremely difficult. However, in the present invention, not only all the color samples are stationed on said four triangle pillars each as one body, but each of said four triangle pillars is short, narrow, and light, so that said triangle pillar on which the color samples are arranged can be hold by one hand easily and it is enough only to pass the handle of said triangle pillar from one hand to the other (one action) for reversing the situation of the top and the bottom of the color samples. As described above, in Claim 8 of the present invention, not by inserting many bundles composed of two or three color samples into said color sample rack, but by arranging them separately on said four triangle pillars, so that it is enabled to compare the natural tooth color with the color samples in Value, Chroma, and Hue in turn by one or two actions, and if necessary, to reverse the situation of the top and the bottom of the color samples by one action, providing an efficient method for dental shade system. Therefore, it could be said that the third embodiment in the present invention is fully satisfying the requirements described in the item (1) on the top of this chapter [SUMMARY OF THE INVENTION] as one of three objects of the present invention to overcome the drawbacks in the prior art. Moreover, in Claim 5 of the present invention, since the color samples having weak Chroma and medium Hue are stationed in line in order of Value leaving spaces between them on the first face of said triangle pillar in the longitudinal direction, it is difficult to approach the two color samples having different Value and stationed apart to patient's natural tooth as close as enough to compare them with the natural tooth color for deciding which Value of the two color samples matches the natural tooth color. However, in the present invention, since the color samples having weak Chroma and medium Hue are arranged in order of Value without spaces on the first face of said first triangle pillar, it is easy to approach the two color samples to be compared as close as enough to patient's natural tooth, so as to be able to decide precisely which color sample matches the natural tooth color. This is the second remarkable point of difference in Claim 8 of the present invention in comparison with Claim 3 of the present invention. Further, in the present invention as described above, since the color samples having medium Hue are arranged but those having yellowish Hue and reddish Hue are not arranged on each face of said first triangle pillar, it does not need to say that the color sample which matches with the natural tooth color in Value and Chroma is easily selected unless the sense of sight is disturbed by the color samples having different Hue. As described above, in Claim 8 of the present invention, in the process of selecting the color sample which matches patient's natural tooth color, it is possible to compare simply and clearly a couple of color samples having different Value, Chroma, or Hue each other with the natural tooth color in Value, Chroma, or Hue, respectively, under the condition that the color samples other than those to be compared do not enter into the field of vision and said couple of color samples and the natural color are held closely and in equal distance. Therefore, it could be said that Claim 8 of the present invention is fully satisfying the requirements described in the item (2) on the top of this chapter [SUMMARY OF THE INVENTION] as one of three objects of the present invention to overcome the drawbacks of the prior art. Further, in Claim 8 of the present invention as described above, to begin with the first step, selecting the first face of said first triangle pillar on which the color samples have weak Chroma and it is easy to decide color in Value, and moving said triangle pillar left and right (in the longitudinal direction) in front of patient's mouth, then select the color sample which matches the natural tooth color in Value. Next, in the second step, rotating said first triangle pillar front and back by 120 degrees at the same position (in the longitudinal direction) with the color sample selected in Value in the first step, select the color sample which matches the natural tooth color in Chroma. Lastly, in the third step, taking up one of said second, third, and fourth triangle pillars the color samples on which have the same Value with the Value selected in the first step, then starting at the color sample which is on the face having the same Chroma with the Chroma selected in the second step among three faces of said triangle pillar taken up in the above, either moving said triangle pillar left and right (in the longitudinal direction) by the width of a color sample or doing the same after rotating said triangle pillar front and back by 120 degrees, decide the color sample which matches patient's natural tooth color in Hue as the final selection. As described above, in Claim 8 of the present invention, it is enabled to decide three coordinates (Value, Chroma, and Hue) of patient's natural tooth color, in three steps divided clearly, and since the decision of three coordinates is simple and clear and never need trial and error in every step described above, user can perceive intuitively the three-dimensional character of color which man's eye sense, represented by three dimensional coordinates composed of Value (lightness level), Chroma (color saturation), and Hue (color). Therefore, it could be said that this fourth alternative of described above is fully satisfying the requirements described in the item (3) on the top of this chapter [SUMMARY OF THE INVENTION] as one of three objects of the present invention to overcome the drawbacks of the prior art. Preferably, in Claim 3 of the present invention of the present invention, the numbers of steps of three coordinates of the color samples arranged on said one triangle pillar in Claim 2 of the present invention described above may be set at 5 steps for Value, 3 steps for Chroma, 3 steps for Hue, including the whole region of color distribution of the natural tooth. Combining them, the dental shade system in Claim 3 of the present invention is composed of 5x3x3=45 color samples at maximum. This composition is aiming to cover the whole region of color distribution of the natural tooth and also to make uniform the distance in color space between the color samples in the sense of sight. Preferably, in Claim 4 of the present invention, by excluding the color samples with low occurrence rates from the color samples arranged on said one triangle pillar in Claim 3, the number of the color samples maybe decreased from 45 at maximum to 26, and the Chromas of a portion of the color samples are revised to intermediate values. This revision is aiming to reduce the cost versus effect ratio by excluding the color samples with low occurrence rates and to revise non-uniformity of distance in the sense of sight in color space between the color samples. Preferably, in Claim 6 of the present invention, the numbers of steps of the color samples arranged on said one triangle pillar in Claim 5 of the present invention may be set at 6 steps for Value (adding 1 step whiter than existing tooth color), 3 steps for Chroma, 3 steps for Hue. Combining them, the dental shade system in Claim 6 is composed of 6x3x3=54 color samples at maximum. This composition is aiming to cover the whole region of color distribution of the natural tooth and also include 1 step whiter than existing tooth color but lightest (whitish) color needed in esthetic dentistry. Preferably, in Claim 7 of the present invention, by excluding the color samples with low occurrence rates from the color samples arranged on said one triangle pillar in Claim 6 of the present invention, the number of color samples may be decreased from 54 at maximum to 29, and the Chromas of a portion of the color samples are revised to intermediate values. This revision is aiming to reduce the cost versus effect ratio by excluding the color samples with low occurrence rates and to revise non-uniformity of distance in the sense of sight in color space between the color samples. Preferably, in Claim 9 of the present invention, the numbers of steps of the color samples arranged on said four triangle pillars in Claim 4, may be set 6 steps for Value (adding 1 step whiter than existing tooth color), 3 steps for Chroma, 3 steps for Hue. Combining them, the dental shade system in Claim 9 is composed of 18 color samples on said first triangle pillar and 9 color samples on said second, third and fourth triangle pillars each, totaling 18+9+9+9=45 color samples at maximum (including 9 repetitions). This composition is constituted, starting from the arrangement composed of 54 color samples at maximum in the sixth embodiment, in which the whole region of color distribution of the natural tooth is covered and 1 step whiter than existing tooth color is added to Value, decreasing 3(Value)x3(Chroma)x2(Hue)=18 color samples by reducing the number of steps of Hue from 3 to 1 among the color samples having Value of 3 steps with low occurrence rates, and adding 9 color samples which are in repetition by the reason of arrangement. Preferably, in Claim 10 in the present invention, further 7 color samples with low occurrence rates may be excluded from 45 color samples (including 9 repetitions) arranged on said four triangle pillars in Claim 9 to 38 (including 9 repetitions) color samples, and the Chroma of a portion of the color samples is revised to immediate value. This composition is aiming to reduce the cost versus effect ratio by excluding the color samples with low occurrence rates and to revise non-uniformity of distance in the sense of sight in color space between the color samples. Preferably, in Claim 11 in the present invention, the shape and/or material composition of the color samples in the present invention may be resembled to the natural tooth. This is used in the conventional art also, and is aiming to make easy to compare the natural tooth color with the color samples and to decrease the influence of light source, by resembling the shape and/or material composition of the color samples to the shape of the natural tooth (for example: anterior tooth) and/or material composition (for example: dentin and enamel of natural tooth) . BRIEF DESCRIPTION OF THE DRAWING Fig. 1 is a bird's-eye view showing the first preferred embodiment of the dental shade system in the present invention. Fig. 2 is a bird's-eye view showing the second preferred embodiment of the dental shade system in the present invention. Fig. 3 is a sectional view of the rotating portion in Fig. 2. Fig. 4 is a bird's-eye view showing the third preferred embodiment of the dental shade system in the present invention. Fig. 5 is a bird's-eye view showing the dental shade system in the conventional art. ILLUSTRATION OF NOTATION OF COLOR SAMPLES V0, V1, V2, V3, V4. V5: steps in Value of color sample C1, C1.5, C2, C2.5, C3: steps in Chroma of color sample Y, M, R: steps in Hue of color sample Note) The unit of numerals shows the unit in the sense of sight based on the CIEIAB color coordinate system. DESCRIPTION OF THE PREFERED EMBODIMENT The preferred embodiments of the present invention are described according to the attached drawings in the followings. In the following description, steps of Value, Chroma, and Hue are set so that the color samples are arranged equidistantly in the sense of sight. In Fig. 1-5, same parts in view of function are designated by same numerals to omit description thereof. (The first preferred embodiment) Fig. 1 shows the dental shade system 1 of the first preferred embodiment in the present invention. This dental shade system comprises an narrow triangle pillar 10 having two handles 14 at the both ends, and on each of three faces 11, 12, and 13 of the triangle pillar 10, eleven positions are set in the longitudinal direction for stationing color samples 50, totaling 11x3=33. In the neighborhood of said handles 14, guards 15 are prepared to avoid the finger holding said handle 14 to contact with the color sample 50. These guards 15 are not necessarily prepared. In the basic composition of the color sample arrangement of the dental shade system 1, as well as the basic composition of the dental shade system 111 in the conventional art shown in Table 1, color samples are put in order combining Value composed of 5 steps (V1, V2, V3, V4, V5, corresponding to the steps of Value 1,2,3,4,5 in the conventional art), Chroma composed of 3 steps (C1, C2, C3, corresponding to the steps of Chroma 1, 2, 3 in the conventional art), and Hue composed of 3 steps of yellowish, medium, reddish (Y, M, R, corresponding to the steps L, M, R in the conventional art), so that totally 5x3x3=45 color samples are arranged. Further, in the practical composition of the color sample arrangement of the dental shade system 1, as well as the practical composition of the dental shade system 111 in the conventional art shown in Table 2, the number of the color samples 50 are reduced from 45 of the basic composition to 26 in the practical composition, by excluding 19 color samples with low occurrence rate. In Table 3, the color sample arrangement on the first face 11 of the triangle pillar 10 of the dental shade system 1 is shown. On the first face 11 of the triangle pillar 10, the color samples 50 having weak Chroma (C1 or C1.5) are arranged, combining Value of 5 steps and Hue of 3 steps, totally 5x3=15 at maximum, are arranged, reduced finally from 15 to 11 by excluding 4 color samples with low occurrence rates, as shown in Table 3. In Table 4, the color sample arrangement on the second face 12 of the triangle pillar 10 of the dental shade system 1 is shown. On the second face 12 on the triangle pillar 10, the color samples 50 having medium Chroma (C2) are arranged, combining Values of 5 steps and Hues of 3 steps, totally 5x3=15 at maximum, and finally reduced from 15 to 5 by excluding 10 color samples (including the color samples marked with x) with low occurrence rate leaving spaces as shown by x marks in Table 4. In Table 5, the color sample arrangement on the third face 13 of the triangle pillar 10 of the dental shade system 1 is shown. On the third face 13 on the triangle pillar 10, the color samples 50 having strong Chroma (C3 or C2.5) are arranged, combining Values of 5 steps and Hues of 3 steps, totally 5x3=15 at maximum, and finally reduced from 15 to 10 color samples by excluding 5 color samples (including the color sample marked with x) with low occurrence rate as shown in Table 5. As described above, the number of the color samples arranged on the three faces 11, 12, and 13 of the triangle pillar 10 of the dental shade system 1 is totally 11 + 5 + 10 = 26, so that the color samples arranged on the first line 115 on the color sample rack 114 of the dental shade system 111 in the conventional art shown in Table 2 are transferred on the first face 11 of the first triangle pillar 10 in the present invention, and also the color samples arranged on the second line 116 are transferred on the second face 12, further the color samples arranged on the third line 117 are transferred on the third face 13. In the dental shade system 1 constituted as described above, the color sample which matches the natural tooth color is selected by doing as follows. First, holding the left and right handles 14 of the triangle pillar 10 by both hands, and approaching the first face 11 having weak Chroma (C1) to patient's natural teeth (maxillary anterior teeth) to be compared, moving left and right the triangle pillar 10, then select the color sample which matches the natural tooth color in Value among Values of 5 steps (V1, V2, V3, V4, V5) arranged in order of Value. At that time, user must pay attention only to the color sample 50 having medium Hue (M) among Hues of 3 steps (Y, M, R), and not to be disturbed by the color sample having the other Hue. As shown in Fig. 1, among the color samples 50 arranged on the first face 11, the top of the color sample having medium Hue (M) is projecting a little more than the other color sample on the same line. The reason is that, at the time of selecting Value, the sense of sight is not to be disturbed by the color samples having yellowish Hue (Y) and reddish Hue (R) which are arranged on both sides of the color sample having medium Hue (M). Secondly, keeping the position of the color sample selected in Value in the longitudinal direction, and rotating the triangle pillar 10 front and back by 120 degrees, then select the color sample which matches the natural tooth color in Chroma among the color samples having Chromas of 3 steps (C1, C2, C3). Thirdly, keeping the position of the triangle pillar 10, and moving it left and right, then select the color sample which matches the natural tooth color in Hue, among the color samples having Hues of 3 steps (Y, M, R), finalizing the selection of the color sample 50 which matches the patient's natural tooth color to be compared. On one hand, in some of the color samples 50 in Table 3 and Table 5, weak Chroma (C1) is replaced by an intermediate Chroma (C1.5) which is weaker a little than medium Chroma (C2) and strong Chroma (C3) is replaced by another intermediate Chroma (C2.5) which is stronger a little than medium Chroma (C2). The reason for the replacements is, as described above on the dental shade system in the conventional art, to revise non-uniformity of distance in the sense of sight in color space caused by excluding the color samples with low occurrence rates. In addition, at the time of selecting the color sample 50, in case of that patient's natural tooth to be compared is mandibular tooth, passing the handle 14 of the triangle pillar 10 from one hand to the other, and revise the difference in shape of the top and the bottom between the natural tooth and the color sample. (The second preferred embodiment) Fig. 2 shows the dental shade system2 of the secondpreferred embodiment in the present invention. This dental shade system 2 comprises an narrow triangle pillar 10 having two handles 14 at both ends, and on each of 3 faces (11, 12, 13) of the triangle pillar 10, 12 positions are set in the longitudinal direction for stationing color samples 50, totaling 12x3=36. On each of six positions among said 12 positions set in the longitudinal direction, the rotary portion51 is provided as shown in Fig. 3, by forming an axis hole 52 in the center and piercing a pivot 53 through said axis hole 52, and by fixing one end of said pivot 53 piercing into a hole 54 formed on one side of the portion 10, and further by inserting the other end of said pivot 53 having a peripheral projection 55 into a hole 56 formed on the other side of the portion 10, so as to be put on and taken off, or to be fixed. In the result, the rotary portion 51 can be rotated by hand around said pivot 53 independent on both sides of the portions 10. In the basic composition of the color sample arrangement of the dental shade system 2, color samples are put in order combining Values of 6 steps arranged in order of Values (V0, V1, V2, V3, V4, V5), Chromas of 3 steps of weak, medium, and strong (C1, C2, C3), and Hues of 3 steps of yellowish, medium, and reddish (Y, M, R), so that totally 6x3x3=54 color samples at maximum are arranged. Further, in the practical composition of the dental shade system 2, the number of the color samples 50 are reduced from 54 of the basic composition to 29 in the practical composition, by excluding the color samples with low occurrence rates. In addition, as described above, among said six steps of Value, V2, V3, and V4 are the Values with high occurrence rates. And. V0 is whiter (lighter) than existing tooth color, but added in the second preferred embodiment due to the necessity of esthetic dentistry. In Table 6, the color sample arrangement on the first face 11 of the triangle pillar 10 of the dental shade system 2 is shown. On the first face 11 of the triangle pillar 10 of the dental shade system 2, the color samples 50 having weak Chroma (C1) and medium Hue (M) are arranged in order of Value, combining Values of 6 steps and Hues of 3 steps, totally 6x3=18 color samples at maximum, and finally reduced from 18 to 6 color samples by excluding 12 color samples (including the color samples marked with x) with low occurrence rates, leaving spaces as shown in Table 6 by x marks. In addition, in Table 6, the color sample positions the row numbers of which are circled are said rotary positions 51. In Table 7, the color sample arrangement on the second face 12 of the triangle pillar 10 of the dental shade system 2 is shown. On the second face 12 of the triangle pillar 10 of the dental shade system 2, the color samples 50 having medium Chroma (C2) or a little weak Chroma (C1.5) are arranged in order of Value, combining Values of 6 steps and Hues of 3 steps, totally 6x3=18 color samples at maximum, and finally reduced from 18 to 12 color samples by excluding 6 color samples with low occurrence rates as shown in Table 7. In Table 7, the color sample positions the row numbers of which are circled are said rotary positions 51. In Table 8, the color sample arrangement on the third face 13 of the triangle pillar 10 of the dental shade system 2 is shown. On the third face 13 of the triangle pillar 10 of the dental shade system 2, the color samples 50 having strong Chroma (C3) or a little strong Chroma (C2.5) are arranged in order of Value, combining Values of 6 steps and Hues of 3 steps, totally 6x3=18 color samples at maximum, and finally reduced from 18 to 11 color samples by excluding 7 color samples (including the color samples marked with x) with low occurrence rates as shown in Table 7. In Table 8 the color sample position the row numbers of which is circled is said rotary position 51. As the result of excluding the color samples with low occurrence rate (including the color samples marked with x) in Table 6, non-uniformity of the distance in color space in the sense of sight is caused between the remaining color samples. To revise it, in Table 7, in the combination of medium Chroma (C2) with yellowish Hue (Y) or reddish Hue (R), medium Chroma (C2) is replaced by a little weak Chroma (C1.5). Similarly, in Table 8, in the combination of strong Chroma (C3) with yellowish Hue (Y) or reddish Hue (R), strong Chroma (C3) is replaced by a little strong Chroma (C2.5). As the final result, the number of the color samples 50 arranged on the three faces 11, 12, 13 of the triangle pillar 10 of the dental shade system 2 is totaled as 6+12+11=29. In the dental shade system 2 constituted as described above, the color sample which matches the natural tooth color is selected by doing as follows. First of all, holding left and right handles 14 of the triangle pillar 10 by both hands, then adjust the rotary portions 51 on the triangle pillar 10 by hand so as to match the positions with the arrangement of the color samples shown in Tables 6-8. For selecting the color sample, first, approaching the face 11 of the triangle pillar 10 on which the color samples having weak Chroma (C1) and medium Hue are arranged in order of Value to the patient's natural tooth to be compared, and moving the triangle pillar 10 left and right, then select the color sample 50 which matches the natural tooth color in Value, from among Values of 6 steps (V0, V1, V2, V3, V4, V5). Secondly, keeping the position of the color sample selected in the longitudinal direction, and rotating the triangle pillar 10 front and back by 120 degrees, then select the color sample 50 which matches the natural tooth color in Chroma among Chromas of 3 steps (C1, C2, C3) arranged on the faces 11, 12, 13 of the triangle pillar 10, respectively. After that, according to the Value and the Chroma selected, final selection by means of the dental shade system 2 is performed as follows. (1) In case that the Value selected is the one of V0, V1, or V5, the occurrence rate of which is low, select the color sample 50 having the Value and the Chroma (C1, C2, or C3) selected and medium Hue as the final selection. (2) In case that the Value selected is the one of V2, V3, or V4, the occurrence rate of which is high, (a) In case that the Chroma selected is weak Chroma (C1), rotating each of the rotary positions 51 arranged on both sides of the color sample selected by 120 degrees so that the color sample is arranged side by side with two color samples having a little weak Chroma (C1.5) and yellowish Hue (Y) or reddish Hue (R), then decide which of the three color samples 50 matches the natural tooth color as the final selection. (b) In case that the Chroma selected is medium Chroma (C2), decide which of the three color samples 50 matches the natural tooth color, from among the color sample selected and the two color samples arranged on both sides of it, the latter two of which have a little weak Chroma (C1.5) and yellowish Hue (Y) or reddish Hue (R) (on the face 12), as shown in Table 7. When sufficient color matching is not obtained by the above decision work, then rotating each of the two color samples (rotary positions 51) arranged on both sides of the color sample selected by 120 degrees, respectively, and decide which of the two color samples 50 having a little strong Chroma (C2.5) and yellowish Hue (Y) or reddish Hue (R) (on the face13) matches the natural tooth color as the final selection. (c) In case that the Chroma selected is strong Chroma (C3), decide which of the three color samples 50 matches the natural tooth color, from among the color sample selected and the two color samples arranged on both sides of it, the latter two of which have a little strong Chroma (C2.5) and yellowish Hue (Y) or reddish Hue (R) (on the face 13), as shown in Table 8, as the final selection. At the time of color selection, in case of that patient's natural tooth to be compared is mandibular anterior tooth, revise the difference of the shape between the natural tooth and the color sample by passing the handles 14 of the triangle pillar 10 from one hand to the other. (The third preferred embodiment) Fig. 4 shows the dental shade system 3 of the third preferred embodiment in the present invention. The dental shade system 3 comprises four narrow triangle pillars, they are, first triangle pillar 10, second triangle pillar 20, third triangle pillar 30, and fourth triangle pillar 40, having handles 14, 24, 34, 44 each on one end and guards 15, 25, 35, 45 each, the arranging positions of the color samples 50 are 6 positions each on three faces 11, 12, 13 of triangle pillar 10, 3 positions each on three faces 21, 22, 23 of triangle pillar 20, 3 positions each on three faces 31, 32, 33 of triangle pillar 30, and 3 positions each on three faces 41, 42, 43 of triangle pillar 40. The basic composition of the color sample arrangement of the dental shade system 3 are constituted by Values of 6 steps (V0, V1, V2, V3, V4, V5) arranged in order of Value, Chromas of 3 steps (C1, C2, C3) composed of weak Chroma, medium Chroma, strong Chroma, and Hues of 3 steps (Y, M, R) composed of yellowish Hue, medium Hue, reddish Hue, totally 6x3x3=54 color samples at maximum. In the practical composition of the color sample arrangement of the dental system 3, the number of the color sample 50 are reduced from 54 in the basic composition to 29 in the practical composition, by excluding 25 color samples with low occurrence rates. In Table 9, the color sample arrangement on the first triangle pillar 10 of the dental shade system 3 is shown. On the three faces 11, 12, 13 of the first triangle pillar 10 of the dental shade system 3, the color samples 50 having medium Hue (M) and composed in combination of Values of 6 steps (V0, V1, V2, V3, V4, V5) and Chromas of 3 steps (C1, C2, C3), totally 6x3=18 color samples at maximum are arranged, reduced from 18 to 17 by excluding 1 with low occurrence rate shown by x mark in the Table. In Table 10, the color sample arrangement on the second triangle pillar 20 of the dental shade system 3 is shown. On the three faces 21, 22, 23 of the second triangle pillar 20 of the dental shade system 3, the color samples having Value V2 which is the first among Values of 3 steps (V2, V3, V4) with high occurrence rates described above and composed in combination of Hues of 3 steps (Y, M, R) and Chromas of 3 steps (C1, C2, C3), totally 3x3=9 color samples at maximum are arranged, reduced from 9 to 7 color samples 50 by excluding 2 with low occurrence rates as shown by x marks in the Table. As shown by x marks on the face 22 in Table 10, the color samples combining medium Chroma (C2) with Hue Y or R are excluded. To revise non-uniformity of color distance in the sense of sight caused between the remaining color samples, weak Chroma (C1) combined with Hue Y or R is replaced by a little weak Chroma (C1.5) on the face 21, and strong Chroma (C3) combined with Hue Y or R is replaced by a little strong Chroma (C2.5). Same is applied with the triangle pillar 30 and 40 in the followings. In Table 11, the color sample arrangement on the third triangle pillar 30 of the dental shade system 3 is shown. On the three faces 31, 32, 33 of the third triangle pillar 30 of the dental shade system 3, the color samples having Value V3 which is the second among Values of 3 steps (V2, V3, V4) with high occurrence rates described above and composed in combination of Hues of 3 steps (Y, M, R) and Chromas of 3 steps (C1, C2, C3), totally 3x3=9 color samples at maximumare arranged, reduced from 9 to 7 color samples 50 by excluding 2 with low occurrence rates as shown by x marks in the Table. In Table 12, the color sample arrangement on the fourth triangle pillar 40 of the dental shade system 3 is shown. On the three faces 41, 42, 43 of the fourth triangle pillar 40 of the dental shade system 3, the color samples having Value V4 which is the third among Values of 3 steps (V2, V3, V4) with high occurrence rates described above and composed in combination of Hues of 3 steps (Y, M, R) and Chromas of 3 steps (C1, C2, C3), totally 3x3=9 color samples at maximum are arranged, reduced from 9 to 7 color samples 50 by excluding 2 with low occurrence rates as shown by x marks in the Table. In the dental shade system 3 constituted as described above, the color samples which matches the natural tooth color is selected by doing as follows. First, holding the handle 14 of the first triangle pillar 10 by one hand, approaching its first face 11 having weak Chroma (C1) among Chromas of 3 steps to patient's natural tooth, and moving the triangle pillar 10 left and right, then select the color sample which matches the natural tooth color in Value from among Values of 6 steps (V0, V1, V2, V3, V4, V5) arranged in order of Value. Secondly, keeping the position of the color sample selected, in the longitudinal direction, and rotating the triangle pillar 10 front and back by 120 degrees, then select the color sample 50 which matches the natural tooth color in Chroma among Chromas of 3 steps (C1, C2, C3). At that time, 1) In case that the value selected is V0, V1, or V5 with low occurrence rate, make the color sample having the Value and the Chroma selected and medium Hue the final selection. 2) In case that the Value selected is V2, V3, or V4 with high occurrence rate, taking up the triangle pillar 20 (V2), 30 (V3), or 40 (V4) each, and further a) In case that the Chroma selected is weak one (C1), approaching the color sample having medium Hue (M/C1) on the first face 21, 31, or 41 of the triangle pillar 20, 30, or 40 each to the natural tooth, decide which color sample 50 matches the natural tooth color, among said color sample and the color samples arranged on both sides of said color sample and having yellowish Hue (Y/C1.5) or reddish Hue (R/C2.5), as the final selection. b) In case that the Chroma selected is medium one (C2), approaching the color sample having medium Hue (M/C2) on the second face 22, 32, or 42 of the triangle pillar 20, 30, or 40 each to the natural tooth, decide which color sample 50 matches the natural tooth color, among said color sample and the color samples which are arranged on both sides of the color sample having medium Hue (M/C1 or M/C3) which appear when rotating the triangle pillar front and back by 120 degrees on the same position in the longitudinal direction and have yellowish Hue (Y/C1.5 or Y/C2.5) or reddish Hue (R/C1.5 or R/C2.5), in other words, decide which color matches the natural tooth color, among those which are on the tops of four arrows shown in Table 10, 11 and Table 12 each, as the final selection. c) In case that the Chroma selected is strong one (C3), approaching the color sample having medium Hue (M/C3) on the third face 23, 33, or 43 of the triangle pillar 20, 30, or 40 each to the natural tooth, decide which color sample 50 matches the natural tooth color, among said color sample and the color samples arranged on both sides of said color sample and having yellowish Hue (Y/C2.5) or reddish Hue (R/C2.5), as the final selection. In the above, in case that the patient's natural tooth to be compared is mandibular anterior tooth, revise the difference of the top and the bottom between the shapes of the natural tooth and the color sample, by passing the triangle pillar from one hand to the other. (The effect of the present invention) As described clearly above, the dental shade system in the conventional art is constituted by many different color samples, making 20 or 3 color samples a bundle and inserting the bundles into a single color sample rack. However, in the present invention, many different color samples are placed separately on one or plural narrow triangle pillars, making one body each. Therefore, in the conventional art, for selecting the color sample which matches patient's natural tooth color, it has been necessary to hold and approach the color sample rack as a whole to patient's mouth and/or taking out and approach two or three bundles of color samples to patient's mouth, several times. However, in the present invention, the selection of Value, Chroma, or Hue is enabled in order by one or two actions each, efficiently. In addition, in the conventional art, to distinguish which color of a couple of different color samples is close to the natural tooth color in Value, Chroma, or Hue, it has been difficult to compare a couple of color samples with the natural tooth in equal distance and in the situation that the other color samples do not enter into the field of vision. However, in the present invention, it is enabled to compare a couple of different color samples with the natural tooth placing them in equal distance and in the situation that the other color samples do not enter into the field of vision, simply and clearly. Further, although the composition of the color sample arrangement of dental shade system in the conventional art has reasonability applying color science, the process for comparing the color samples with the natural tooth color has neither been simple nor clear. In the present invention, since the process for comparing the color samples with the natural tooth is simplified and the arrangement of the color samples is clarified, with use of the dental shade system in the present invention, user can be enabled to perceive intuitively the three dimensional character of color which man's eye sense, and it would contributes to improve user's reproducing technique of tooth color. The basic composition of color sample arrangement of the dental shade system 111 in the conventional art Row No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 The 1st line 1L/1 1M/1 1R/1 2L/1 2M/1 2R/1 3L/1 3M/1 3R/1 4L/1 4M/1 4R/1 5L/1 5M/1 5F The 2nd line 1L/2 1M/2 1R/2 2L/2 2M/2 2R/2 3L/2 3M/2 3R/2 4L/2 4M/2 4R/2 5L/2 5M/2 5F The 3rd line 1L/3 1M/3 1R/3 2L/3 2M/3 2R/3 3L/3 3M/3 3R3 4L/3 4M/3 4R/3 5L/3 5M/3 5F The practical composition of color sample arrangement of the dental shade system 111 in the conventional art Row No. 1 2 3 4 5 6 7 8 9 10 11 The 1st line 115 1M/1 2L/1.5 2M/1 2R/1.5 3L/1.5 3M/1 3R/1.5 4L/1.5 4M/1 4R/1.5 5M/1 The 2nd line 116 1M/2 X 2M/2 X X 3M/2 X X 4M/2 X 5M/2 The 3rd line 117 X 2L/2.5 2M/3 2R/2.5 3L/2.5 3M/3 3R/2.5 4L/2.5 4M/3 4R/2.5 5M/3 The color sample arrangement on the first face 11 of the triangle pillar 10 of the dental shade system 1 Row No. 1 2 3 4 5 6 7 8 9 10 11 Value V1 V2 V2 V2 V3 V3 V3 V4 V4 V4 V5 Chroma C1 C1.5 C1 C1.5 C1 C1.5 C1 C1.5 C1 C1.5 C1.5 Hue M Y M R Y M R Y M R M The color sample arrangement on the second face 12 of the triangle pillar 10 of the dental shade system 1 Row No. 1 2 3 4 5 6 7 8 9 10 11 Value V1 X V2 X X V3 X X V4 X V5 Chroma C2 X C2 X X C2 X X C2 X C2 Hue M X M X X M X X M X M The color sample arrangement on the third face 13 of the triangle pillar 10 of the dental shade system 1 Row No. 1 2 3 4 5 6 7 8 9 10 11 Value X V2 V2 V2 V3 V3 V3 V4 V4 V4 V5 Chroma X C2.5 C3 C2.5 C2.5 C3 C2.5 C2.5 C3 C2.5 C3 Hue X Y M R Y M R Y M R M The color sample arrangement on the first triangle pillar 10 of the dental shade system 3 Row No. 1 2 3 4 5 6 Hue M M M M M M Value V0 V1 V2 V3 V4 V5 Chroma Face 11 C1 C1 C1 C1 C1 C1 Face 12 C2 C2 C2 C2 C2 C2 Face 13 C3 X C3 C3 C3 C3

Claims: A dental shade system (1) having a plurality of different color samples (50) arranged equidistantly in the sense of sight in color space in terms of three-dimensional coordinates of Value (lightness level) Chroma (color saturation), and Hue (color), characterized in that a plurality of color samples (50) is placed separately on at least one narrow triangle pillar (10), wherein color samples representing plural steps of Value and HUE are arranged in order or in combination in a longitudinal direction on each of three faces (11, 12, 13) of said triangle pillars (10) and wherein color samples representing plural steps of Chroma are arranged on each of three faces (11, 12, 13) of said triangle pillar (10), so that user can decide the three coordinates of tooth color which match a natural tooth color. The dental shade system as set forth in claim 1, wherein all color samples are arranged on one narrow triangle pillar, stationing on the first face of said triangle pillar the color samples having weak Chroma and medium Hue in order of Value leaving spaces in the longitudinal direction, and stationing on both sides of each said color sample the color sample having the same Value and Chroma with each said color sample and having more yellowish Hue and more reddish Hue than said color sample, respectively and, on the same position with each said color sample in the longitudinal direction, the color samples having the same Value and Hue with each said color sample, are stationed on the second and the third faces of said triangle pillar, among which the color sample stationed on the second face has medium Chroma and the one stationed on the third face has strong Chroma, respectively. The dental shade system as set forth in claim 2, wherein color samples are arranged on said one triangle pillar, combining Values of 5 steps, Chromas of 3 steps, Hues of 3 steps, composed of totally 5x3x3=45 color samples at maximum. The dental shade system as set forth in claim 3, wherein the number of said color samples are reduced from 45 to 26, excluding 19 color samples the occurrence rates of which are low, and the Chromas of a portion of said color samples are revised to intermediates. The dental shade system as set forth in claim 1, wherein the color samples having weak Chroma and medium Hue are stationed on the first face of said triangle pillar in order of Value leaving spaces in the longitudinal direction, the color samples having the same Value and Hue with each said color sample are stationed on the second and third faces of said triangle pillar on the same position with each said color sample in the longitudinal direction, among which the color sample stationed on the second face has medium Chroma and the one stationed on the third face has strong Chroma respectively, the color samples having more yellowish Hue and more reddish Hue than each said color sample are stationed on both sides of each said color sample, and a rotary mechanism by which the each position of said color samples having yellowish Hue and reddish Hue rotates around the axis of said triangle pillar by hand is added. The dental shade system as set forth in claim 5, wherein the number of steps of the color samples arranged on said one triangle pillar are set 6 steps for Value (adding 1 step whiter than existing tooth color), 3 steps for Chroma, 3 steps for Hue, combining which, the dental shade system is composed of 6x3x3=54 color samples at maximum. The dental shade system as set forth in claim 6, wherein the number of color samples is reduced from 54 at maximum to 29, by excluding 25 color samples with low occurrence rates, and the Chromas of a portion of the color samples are revised to intermediates. The dental shade system as set forth in claim 1, wherein many different color samples are arranged separately on four said narrow triangle pillars, comprising: First triangle pillar, on the first face among the three faces of said triangle pillar, the color samples having weak Chroma and medium Hue are arranged in order of Value without space in the longitudinal direction, and on the same position with each said color sample in the longitudinal direction, the color samples having the same Value and Hue with each said color sample are stationed on the second and third faces of said triangle pillar, among which the color samples stationed on the second face have medium Chroma and the ones stationed on the third face have strong Chroma, respectively, Second triangle pillar, on the first face among the three faces of said triangle pillar, the color samples having the first (lightest) Value among Values of 3 steps with high occurrence rates and also having weak Chroma are arranged in order of yellowish Hue, medium Hue, and reddish Hue in the longitudinal direction, and on the second and the third faces of said triangle pillar, the color samples having the same Value and Hue with each said color sample are stationed, on the same position with each said color sample in the longitudinal direction, among which the color samples stationed on the second face have medium Chroma and the ones stationed on the third face have strong Chroma, respectively, Third triangle pillar, on which the color samples are arranged replacing the first Value by the second Value among Values of 3 steps, in the color sample arrangement on said second triangle pillar described above, and Fourth triangle pillar, on which the color samples are arranged replacing the first Value by the third Value among Values of 3 steps, in the color sample arrangement on said second triangle pillar described above. The dental shade system as set forth in claim 8, wherein the numbers of steps of the color samples arranged on said four triangle pillars are set 6 for Value, adding 1 step whiter than existing tooth color, 3 for Chroma, and 3 for Hue, combining which the arrangement is composed of 18 color samples on said first triangle pillar and 9 color samples on said second, third, and fourth triangle pillars each, totaling 18+9+9+9=45 color samples at maximum 436 without repetition. The dental shade system as set forth in claim 9, wherein the number of the color samples are reduced from 45, 36 without repetition, to 38, 29 without repetition, by excluding 7 color samples with low occurrence rates, and the Chromas of the color samples are revised in a part to intermediates. The dental shade system as set forth in claim 1-10, wherein the shape and/or material composition of the color samples arranged on said one or plural triangle pillars are resembled to the natural tooth.

Inventors: HOBO SUMIYA, HOBO, SUMIYA
Applicants: RAUTER VITA ZAHNFABRIK, VITA ZAHNFABRIK H. RAUTER GMBH & CO. KG
Application year: 2000
Main classification: A61C19
IPC codes: A61C19, A61C13