Crown & Bridge Shade Selection PDF

University of Jordan Dentistry 019 Crown & Bridge Written By: Mira Shallah Corrected By:Mhmd Bader ! Doctor: Islam Abd Alraheam Sheet# 9 Doctor Illustrations In Black ‫اﻟﻤﺤﺎﺿﺮة ﻣﻦ ﻛﻠﯿﺔ اﻟﻔﻨﻮن اﻧﺠﻮي‬ 1 SHADE SELECTION IN DENTISTRY OBJECTIVES Students should be able to learn the following points...

University of Jordan Dentistry 019 Crown & Bridge Written By: Mira Shallah Corrected By:Mhmd Bader ! Doctor: Islam Abd Alraheam Sheet# 9 Doctor Illustrations In Black ‫اﻟﻤﺤﺎﺿﺮة ﻣﻦ ﻛﻠﯿﺔ اﻟﻔﻨﻮن اﻧﺠﻮي‬ 1 SHADE SELECTION IN DENTISTRY OBJECTIVES Students should be able to learn the following points in this lecture: 1) The color attributes according to Munsell color order system and CIELAB color system. 2) The concepts of shade matching in dentistry using both of visual shade matching and instrumental color analysis techniques. 3) The different shade guides available in the market ,which guide we should used and how to use each one. 4) The importance of duplicating the shade in the final restoration that you provide for your patient. Munsell Color Order System • • It is one of the past method to visually quantify color. It has three attributes of color: 1) Hue - Is defined as the particular variety of a color, or the family of the color. - It can be red hue, green hue, yellow hue,...etc. - It is determined by the wavelength of the reflected and or transmitted light observed. - The shorter the wavelength ↓ the closer it is to the violet portion of the spectrum. - The longer the wavelength ↑ the closer it is to the red portion of the spectrum. - In the Munsell color system, Hues are arranged around the wheel (it is a diagram representing Hue, Chroma and Value . Hue of the color or the family of the color arranged around a wheel of this figure). 2 2) Chroma Value Chroma - Is defined as the intensity or the saturation of a Hue. - In the Munsell color system, chroma is the X axis. -For example the Green hue ,if we go from the center toward the other end of the x-axis ,the saturation of the color would be more . 3) Value - Is defined as the relative lightness or darkness of a color or the brightness of an object. - It is a direct consequence of the amount of light energy the object reflects and or transmits. It differs from the hue which is the wavelength of the transmitted or reflected light. - A restoration that has too high value (too bright) maybe easily detected by an observer ,even if the observer is not a dentist which is bad. L -If you provide a patient with a crown for central incisor with a very high value (higher then the adjacent teeth value) ,it will be easily detected . -The value is very sensitive aspect in shade matching ,you should get used to detect high and low value object . - In the Munsell color system, Value is the Y axis. -The bottom of the axis is Black which’s the lowest brightness ,going up toward the white which’s the highest value . -Colored and black & white picture-The first thing that your eyes would detect in each pic is the firework ,why is that? -Because the amount of energy reflected by this object is way higher than the amount of energy reflected by the other objects .The firework is brightest which means our eyes detect it easy compared to the adjacent structures . 3 àA clinical pic of one of the Dr patients ,having implant retained crown on the upper left central incisor ,in B&W pic you cannot tell if there is differance in the value ( brightness)between the restoration and the adjacent teeth. Dr Islam abd alraheam àIn colored pic , we can detect a very slight difference between the crown and the rest of the teeth ,the difference is in the saturation of the color( chroma) not the value . àThe adjacents have a bit of yellow color in them because this pic is taken a year after the crown insertion which relapsing of the bleach happen ,while the porcelain crown is stable .We can solve this easily by providing the patient bleaching tray for one or two days . àWhen the problem is not a value ,so it is easy to solve . CIELAB Color System • • • • • It is used to quantify color for almost exclusively for color research in dentistry. Because in this system we are dealing with numbers (once you deal with numbers then this type of work will be applicable for research ☺). It was introduced in 1976 and recommended by the International Commission on Illumination. Not exclusively used in dentistry it is used originally in industry . The attributes can be converted into numerical parameters. It has three attributes of color: 1) L*: represents the lightness and darkness, similar to the value in the other system. 0 is Black and 100 is white 2) a*: represents the chromatic characteristic of the color. A+ direction we are heading to the red color ,a- direction heading to the green color . 3) b*: represents the chromatic characteristic of the color. Again! B+ value it is a yellow color ,b- value it is a blue color. 4 • • • The L value : when we go to the bottom is black ,to the top is white . The B+ value is yellow ,the b- is Blue . The A+ value is red ,the a- is Green. àFrom the equation we can get the ΔE value which means the difference in color ,we don’t really use this value in clinical dentistry as much ,but it is used in research . Shade Matching Techniques Instrumental shade matching (discussed in p14) Visual shade matching technique: -By using our eyes to check the shade and choose it . -Most commonly used method because it is easy -Factors affecting the visual shade selection: 1) Lighting 2) Subjectivity of human vision 3) The object 1) Lighting - An object that is perceived as a certain color absorbs all light waves corresponding to other colors and reflects only the object’s color. -Why is the apple red for example? : because the red apple absorbed all the wavelengths or all the light waves of the different colors and it only reflected the red portion of the light. • The type of light available in our clinics will affect the shade matching skills ,for example : -Daylight is not constant through out the day so it is not recommended to pick your shade under daylight ,because at noon when the sun is vertical on the Earth the amount of white-yellow light is different than the white-yellow light portion at 7 A.M. or at 6 P.M. So we need to use something else where it is more standardized all the time. L *-A light source with a color temperature close to 5500 K ( close to white color) and color rendering index of greater than 90 ,IS RECOMMENDED. J -Incandescent light bulb emits relatively high concentration of yellow waves L ,that’s why it is not recommended. The incandescent light bulb or lamp is a source of electric light that works by incandescence, which is the emission of light caused by heating the filament.) ! ‫ﻟﻣﺑﮫ ﻗدﯾﻣﮫ‬ 5 -Fluorescent ceiling fixtures gives high concentration of blue L it is not recommended either. (‫)ﻟﻤﺒﮫ ﻧﯿﻮن‬ *-Color corrected fluorescent lighting is recommended J because it has a color temperature of 5500 Kelvin and color rendering index of 90 . *-Auxiliary light source can be used to overcome the drawbacks of the office lighting or correct the office light . • Shade matching environment: - The colors of the dental operatory, clothing of the dentist and dental assistants, the patient’s clothing and the dental drape may influence the perceived color of the patient’s teeth and shade guide. - The ideal tone to avoid that is neutral gray. So a lot of dental offices painted the walls by neutral gray or light blue because these are the complementary colors of white and yellow (which are the color of our teeth) . Complementary colors are pairs of colors which, when combined or mixed, cancel each other out (lose hue) by producing a grayscale color like white or black. When placed next to each other, they create the strongest contrast for those two colors. Complementary colors may also be called "opposite colors". 2) Subjectivity of human vision • The eye: which perceive the light and then the brain will analyze it HOW? : - Light from an object enters the eye and acts on receptors in the retina (rods and cones). - Rods: used under low lighting conditions (scotopic vision). Allows interpretation of the brightness (Value). - Cones: active under higher lighting condition (photopic vision). Allows interpretation of the color. -Three types of cones: sensitive to red, green and blue. The combination of these colors will give us the rest of the colors . ‫اﻟﻠﻲ ھﻢ اﻷﻟﻮان اﻷﺳﺎﺳﯿﺔ‬ - Cones located in the center of the retina while rods on the periphery. 6 -The retina of the eye-The number of the rods are more than the cons ,that gives an indication why the human eye is sensitive to value compared to colores . -Therefore we detect the brightness very easily because we have more rods receptor in the retina. • Color adaptation: -The human eyes get adapted if you look at an object for longer time .You look at the object first time then after your eyes get adapted you will not be able to see the color the same as you saw before. -It is important in shade matching that you detect the color very quickly in the first few seconds otherwise you will not be able to . - Color vision decrease rapidly as a person stares at an object. • Deceptive color perception: - The brain can be tricked in how it perceives color. -Color is influenced by surrounding colors, particularly complimentary ones. -In the pic you will be surprized to know that both squares A and B have the same color . -The one on the left : A seems to be dark gray ,and B light gray . -The right pic : A and B have medium gray color -While in reality have the same color ,the only difference is the surroundings so our brain got tricked . -You can read more about color illusion it is intresting actually . 7 -Same patient ... different surrounding – -Same patient in different lipsticks . -In each of them the brightness of the teeth looks different due to different surroundings . -When she wear a dark lipstick the teeth might look very bright or white, while when she is wearing more nutral lipstick color the teeth would look more neutral . -The complexion of the patient will affect too : the african or dark skin color ,their teeth will look really white . • Color blindness (color insuffiency) - Affect 8% of the male population . more in males. -It would affect shade matching skills significantly. -In pic :the test that is commonly used to detect blindness. -Normal people with normal color vision will see the numbers inside the circles -Abnormal color vision will not see these numbers ,and might see other numbers . -So if you have color insufficency you have to use an assisstant or someone else to choose the sade . 3) The object • Metamerism: -When two objects appear to be a match in color under a given lighting condition but have different spectral reflectance . -we have two balls one is red and one is green ,in a specific light they appear to have the same color ,but in real life they do have two different colors. In Dentistry : for example you deliver the crown for upper central ,under the lighting condition of the clinic you will see the tooth is matching the adjacent and you and the pt will be happy ,after that the pt come back complaining from the shade under the sun too fake or not matching the adjacent. Because the light will hit the central incisor before any teeth and it is the first thing seen in the mouth ,it is very tricky to shade matches central incisor . -So Metamerism has significant effect on shade matching. Metamerism is a phenomenon that occurs when two colors appear to match under one lighting condition, but not when the light changes. Metameric matches are quite common, especially in near neutral colors like grays, whites, and dark colors. As colors become lighter or more saturated, the range of possible metameric matches becomes smaller. 8 • Fluorescence: -Fluorescent materials, such as tooth enamel, -Florescence means: the object will re-emit radiant energy at a lower frequency than it is absorbed. -In the coolored pic ,the composite restoration looks not bad ,but under florescent light it is really bad. -After we did that restoration using the correct material and correct layering technique the final restoration has the same florescance ability as in enamel ,and this is one of the most difficult skills to have (to reproduce the florescence of enamel). - ‫ اﻟﺴﺆال اﻟﻘﻮي‬When people will see you under florescent light like that ? if you do bowling ,the bowling hall have florescent light everywhere ,so if you have a restoration on upper anterior tooth try not to go to bowling halls J . • Opalescence: -Natural teeth, particularly at their incisal edges, exhibit a light scattering effect that creates the appearance of bluish white colors as the teeth are seen at different angles. -Because as you know at the edges there is basically enamel ,when the light hits the edges some of it will get scattered ,and that scattered light will create the bluish white color of the incisal edges. -So it is important when you choose the shade to check for the opalescence existence in the adjacent incisal edges . -To reproduce the tooth we should ask the lab to have darker neck ,internal mamelons structures ,if the pt have demineralization spots or white spots and if the incisal edges have whitish bluish or opalescence appearance, we should draw them and ask the lab to recreate that. -This is very important to master recognizing what the natural teeth have and write them properly for the lab so the technician can recreate these specifications in the final restoration. 9 Shade Selection System 1) Vita Lumin vacuum shade guide (VITA ,classic): -Hue is picked first ( A, B, C, D) then chroma and value is selected. A: Beige color ‫ اﻟﻠﻮن اﻟﺒﯿﺞ‬J B: milky white and yellowish C: grayish D: brownish ,or red-brown color. - For initial hue selection, the region with the highest chroma (the cervical region of canines should be used). When you have the pt sitting and you ready to pick the shade ,it is recommended to look first at the cervical area of the canine to pick the right hue ,because it has the highest chroma or saturated region that’s why it makes it easy for you to pick the hue. -After you pick the hue ,then go to pick the chroma and value by putting the sade tab adjacent to the natural teeth (at the same level ,not behind or front of it) so your eye detect the correct shade . 2) Vitapan 3D-Master shade guide - Came to overcome the weaknesses were found in previous teeth guide. -It covers the entire tooth color space (provides more selection of shades). -Actually this shade guide was designed according to ΔE lab unit in the CEILAB color system. - The shade samples are grouped in six lightness levels (value) each of which has chroma and hue variations on evenly spaced steps. Each value has a different chroma and value. - Value is selected first (0,1,2,3,4,5) then hue (L,M,R) and chroma (1, 1.5, 2,3). - 1M2 shade: 1 is the value,/ M is the hue,/ 2 is the chroma. 10 3) Vita linear shade guide 3D master: - Same like the previous one but has easier arrangement. -Comes in a box ,once you open it you will see the all values available in the shade guide . -When you pick the value of 2 for example you go to the tab where it has the value 2 ,that tab would have all the shade guides (hue and chroma) and you can choose from them. 4) Dentin shade guide -When a translucent all ceramic system for a crown or veneer is used, communicating the shade of the prepared dentin to the dental laboratory is helpful. -It is important to have them if you are doing all ceramic restorations with high translucency like Emax crowns , you draw prepartion shade to the lab so they know if they have to block the underlying color or not. -Very important when a pt with a previous trauma to the upper central or have a previous PFM ,the tooth will be discolored or look gray . Otherwise the final restoration (if it was all-ceramic restoration for example) will come too translucent and the dark underlying shade of the prepared tooth will be shown through the crown. 5) Gingival shade guide: -we know that gingiva is pink but there is a hundred degree of pink . -With very long crowns and high smile lines ,it is ugly to have white porcelain replacing the soft tissues . -so we had to add some pink porcelain to mimic the lost gingival tissue, therefore it is important to pick the shade of it similar to the pt gingiva. 11 6) Custom shade guide -In some patients it is difficult to pick the shades ,you tried using multiple shade guides and none of the available guides gave you the specific shade the pt has. -In this case you customize your shade . -In the pic ,the pt had implant retained bridge replacing lower central and lateral ,the first restoration didn’t really look good so we customize a shade . -What actually did is we took a silicone material and made a mold of a tooth from the shade guide ,then we place the composite in the mold to get the shade of the tooth ,after thet we use the staines to color this composite tooth. Then once we satisfied with the shade of this composite we send it to the lab (they will replicate it and use it in the final restoration ) -the last pic ,the final restoration which matches very well the adjacent teeth. Summary of guidelines for visual shade matching: - Shade matching should be made under balanced lighting and in an appropriate shade matching environment with (neutral color) gray or pastel color walls/cabinets. - Anything on the patient that influences the shade matching, including brightly colored clothing, should be draped, lipstick and even the apron (napkin) should be removed. àManufacturer do the aprons light blue ,gray (neutral colors that will not affect the shade matching step) - The teeth to be matched should be clean. If plaque or stains are on those teeth when the shade is selected ,and then you do cleaning or polishing then the final restoration will look more yellow or look different from the new clean adjacent teeth. Logically do cleaning before the shade matching step. 12 - Shade matching should be made at the beginning of a patient’s visit. Tooth color increases in value when the teeth are dry. Because teeth dehydrate with time under isolation so they will look whiter or higher in value and the therefore the restoration will look too bright L - Patient should be viewed at eye level. A viewing distance of 10 inches (25 cm) should be adopted. If the pt is too high or too low ,that’s mean you are looking at the teeth at an angle and this is not recommended. - Shade matching should be made quickly (less than 5 seconds) to avoid eye fatigue and adaptation. If you cannot just relax your eyes and look at something different than teeth then come back again to pick the shade . -DON’T STARE AT THE TEETH FOR LONG TIME.- The dentist should rest his or her eyes on a neutral gray surface. - To select the appropriate hue, the canine tooth is recommended for comparison because it has the highest chroma of the dominant hue. - The dentist can select an appropriate value by squinting the eyes. The Dr thinks because by this we mainly using the periphery of retinal receptors (more rods ,responsible for brightness detection) - A second opinion is always good! + the patient opinion . - If an exact match cannot be selected, a shade tab with the lower chroma (less saturation of the color) and highest value should be selected. àIf the final restoration comes and you try it in and the chroma is low ,It is easy to correct by adding some stains to make it darker . But if the bulk of the porcelain is dark (higher chroma) there is no way to make it lighter . àIf the value is high the technician can lower it down by applying some stains .But if you pick a low value then the stains cannot get the value higher . - The dentist should match the polychromatic nature if the tooth being matched (cracks, Hypocalcification, and translucency of the incisal edge, surface texture ..etc), so all these should very carefully communicated to the lab . àOur patients teeth are not monochromatic ,it doesn’t have same color from cervical area to incisal area, usually we do have different shades in the same tooth . - Sending high quality photograph and shade mapping to the dental technician are Helpful (before you start the prep) . - Custom shade guide is needed in some cases. 13 Instrumental shade selection Spectrophotometer -There are some instrument in the market are designed to help the dentist to pick the correct shade . -Spectrophotometer : has a tip emits some specific light at the tooth ,the tooth will absorb and then reflect some wavelengths . The receptor in the spectrophotometer will analyze these wavelengths and then give you the recommended shade (as a classic shade guide “A2” ) then it gives what it comparable with it in Vitapan 3D-Master shade guide (2M2). -In some of these spectrophotometer it does give you which ceramic material to use and what is the block number that we use for this type of restoration . VERY IMPORTANT NOTES: àSome patients have surface textures on their teeth so you have to respect that(you can creat an orange peel effect by using a yellow needle bur ),if he has some roughness on the enamel don’t over polish the restoration otherwise it will look fake. àIf the tooth have the same value as the adjacent teeth it will look natural even if it doesn’t have the very accurate chroma. Little darker or lighter in term of chroma it is forgiven. But if the value too different then it will be detected very easily . PLEASE GO TO THE VIDEO FROM 44:00 TO SEE THE DOCTOR DISCUSSION ON HER CLINICAL PICTURES AND SOME USEFUL VIDEOS<3 14