Color in Dentistry: A Clinical Guide to Predictable Esthetics

By Stephen J. Chu, Rade D. Paravina, Irena Saile and Adam J. Mieleszko

Predictable shade matching in dentistry remains a significant challenge for clinicians in daily practice. Color is an important aspect in the esthetics of teeth and dental restoration fabrication, and color discrepancy can mar restorative results, even when other aspects (marginal fit, occlusion, and morphology) are adequate. This book provides step-by-step protocols to help dental professionals accurately match, communicate, and reproduce the color of teeth and gingiva. These authors demonstrate how to implement color science in simple problem-solving instructions for predictable esthetics in both clinical protocols and laboratory techniques. An extensive presentation of clinical cases is included to illustrate the use of recommended protocols in general practice. An outstanding contribution to the practice and theory of color management in contemporary dentistry.

• Language: English
• Publisher: Quintessence Publishing Co, Inc
• Release date: Oct 18, 2019
• ISBN: 9780867157611

Book preview

COLOR EDUCATION AND TRAINING

IN THIS CHAPTER:

•Cultivating the skill of shade matching

•Currently available shade-matching publications and programs

Many factors influence our ability to achieve accurate shade-matching results, including subjectivity, shade-matching tools, materials, methods, and conditions. Nonetheless, the importance of color education and training should not be underestimated, as Sproull noted in 1974: The technology of color is not a simple matter that can be learned without study; neither is it a complicated matter beyond the comprehension of dentists.¹ Color appearance is frequently of critical importance to the final outcome of dental restorations and their acceptance by patients. This is why education and training should be the first step of a process that should result in the predictable and enhanced esthetic outcome of dental restorations.

Cultivating the Skill of Shade Matching

Successful musicians, painters, and other artists are both gifted and well educated in their craft, and yet they continue to practice and improve their skills. In contrast, little effort is made to assess whether the average dental professional has an eye for shade matching. Moreover, education on color is frequently not even part of the undergraduate or graduate dental school curriculum.¹–³ Years of shade-matching experience practiced under inappropriate conditions, using inadequate tools and methods, can hardly be called color training. The literature shows that dentists often overestimate their color-matching and reproduction abilities. When asked to match 16 corresponding pairs from two VITA classical A1-D4 shade guides using the visual method, the pre- and postdoctoral participants correctly matched only 50%.⁴ In another study, which closely resembled clinical dentistry in that there was no exact match, the observer’s choice was the second or third best match.⁵

Several surveys have been conducted on color education. The first one, in 1967, revealed that only three institutions (of the 115 institutions that responded) offered a color science course, and only 2.3 classes, on average, referred to color topics.¹ In another survey, core curriculum and elective courses on color were taught at 26% and 17%, respectively, of the 69 responding schools.² A third survey related to teaching of color in predoctoral and postdoctoral dental education was published in 1992. Responses were received from 138 institutions.³ The mean number of hours devoted to color topics was 6.6, and 50% of the schools reported a lack of a color-balanced environment. In addition, 85% of respondents believed that there was a need to develop a new, systematic shade guide. It was concluded that additional efforts should be made regarding the study, research, and application of color science in the dental profession, particularly in undergraduate education.

A fourth survey was published in 2010.⁶ There were a total of 130 responses from North America, Europe, South America, Asia, and Africa. It was reported that a course on color in dentistry was included in the dental curriculum of 80% and 82% of pre- and postdoctoral programs, respectively. Significant differences in the number of hours dedicated to teaching of color were recorded at each level (4.0 versus 5.5 hours, respectively). Significant differences were also reported between the levels for the following: teaching on negative afterimages, color rendering index, VITA Bleachedguide, VITA 3D-Master shade guide, digital camera and lens selection, composite resins, and maxillofacial prosthetic materials, with significantly higher percentages recorded for postdoctoral programs. VITA classical A1-D4 and VITA 3D-Master were the most frequently taught shade guides.

It has been demonstrated in multiple studies that shade-matching devices are more reliable than the predominantly used visual method.⁷ It should be noted that shade-matching results obtained using the visual method were most probably below the expectations of many. Two similar studies, performed on different continents and on different shade-matching tasks, reported pretty similar results: 70% to 80% of the participating dental students were not able to select the best matching tab from the shade guide, while barely 50% of students selected one of three best matches. However, the latter percentage increased to over 72% upon color education and training, which is in accordance with other studies that reported that education and training can improve one’s color-matching skills.⁷,⁸

Currently Available Shade-Matching Publications and Programs

Several multimedia color education and training programs are now available (Table 1-1). Each program has its own unique features, but they all are designed with the same intention: to educate/train dental professionals in color matching. A brief description of each program is provided below.

Color Matching Curriculum (CMC; Fig 1-1) is a half-day continuing education (CE) module published by the Society for Color and Appearance in Dentistry (SCAD) and available through the SCAD website upon request.⁹ This CE module has been developed for dental students and dental professionals. The main motivation for this CE course was the notion that shade matching in clinical dentistry still leaves a lot to be desired. Color mismatch of restorations in the anterior zone is a ubiquitous situation causing frustrations to the patient and practitioner alike, while the repetitive corrections of mismatches are time-consuming and expensive. Given patients’ demands to receive restorations that emulate the natural dentition, this state-of-the-art combined didactic/hands-on course is designed to enhance clinical outcomes. The course provides an update on new developments on this subject, revisits traditional teaching materials and introduces improvements, and provides a hands-on section on visual and instrumental shade matching. It consists of the following segments:

•Color concepts and resources

•Visual color matching

•Hands-on I

•Color-matching instruments

•Hands-on II

•Dental Color Matcher (homework)

The didactic portion of the CMC module provides step-by-step instructions and emphasizes color concepts and resources, methods, conditions, and tools for visual and instrumental shade matching and communication on color and appearance, all of which are essential to master a plan for successful color matching in both the office and dental laboratory. Examples and practical suggestions are provided. Some of the learning objectives include understanding color, learning about advanced shade-matching conditions and methods, contrasting dental shade guides and elaborating color-related properties of dental materials, reviewing the state of the art in tooth-whitening monitoring, and learning about resources for color education and training in esthetic dentistry.⁹

Fig 1-1 Color Matching Curriculum, a free half-day continuing education module published by the Society for Color and Appearance in Dentistry (SCAD).

Fig 1-2 CMC Hands-on I (visual color matching) recording sheet.

The hands-on portion is divided into two parts. Based on the fact that tooth color-matching results can improve by using a group-learning approach in a clinical setting, groups of four participants are created in Part I (Fig 1-2). One of the participants serves as patient, while the remaining three match the shade of one of his or her maxillary central incisors (an intact natural tooth is preferred over a restored one). This cycle is repeated four times so that each group member serves as the patient. The shade-matching technique introduced in the didactic part of the module is implemented during this hands-on part, with an option for using more than one shade guide in the four cycles. The shade-matching results, the quality of the selected match (rated from 1 [huge mismatch] to 5 [excellent match]), and the difficulty of the task (rated from 1 [very difficult] to 5 [easy]) are recorded on a sheet of paper without allowing group members to see each other’s results. Upon completing each cycle, the three group members that matched the same tooth work as a team and record a team shade match. At the end of these exercises, each user reports his or her results, and all participants provide their comments and perspective.

Fig 1-3 Color competency test. (a) Matching pairs of scattered tabs from two VITA classical A1-D4 shade guides, with the shade designations in one set of tabs being masked. (b) Matched pairs.

Depending on available resources, it is advised that color-corrected light (ceiling, floor, table, or handheld light), light gray bibs, and gray paper, cloth, or cardboard for resting the eyes are used during Part I of the hands-on portion of CMC. Ideally, an exercise on matching pairs of tabs from two identical VITA classical A1-D4 shade guides, with the shade designations in one set of tabs being masked, should be performed by each participant during the CMC module (Fig 1-3). The results should be recorded and interpreted in accordance with ISO/TR 28642: An observer must correctly match at least 75% (12 pairs) or 85% (14 pairs) of the tab pairs presented in the test to be considered to have average or superior color discrimination competency, respectively.¹⁰ Hands-on II is related to demonstration and/or work with one or more color-measuring devices.

Dental Color Matcher (SCAD and Vita Zahnfabrik; Fig 1-4) is a free online education and training program. It is hosted through the SCAD website (www.scadent.org) and serves as the homework supplement for the CMC module.¹¹ This program has been used by thousands of dental professionals and students from over 100 countries and is a combination of color-matching exercises and a didactic video.

The first of the onscreen exercises, Closest match I, asks the user to determine the best match to four target shade tabs using VITA Linearguide 3D-Master tabs (Fig 1-5). Afterward, the 25-minute video provides information on the role of color in contemporary esthetic and cosmetic dentistry, shade-matching skills and success of dental professionals, color dimensions and the color of human teeth, and color-matching methods used in dentistry. The video particularly addresses influences on the visual method, such as years in practice, sex, education and training, color-matching conditions, as well as techniques to achieve predictable success with visual shade matching.¹²

Fig 1-4 Dental Color Matcher, a free educational and training program for esthetic dentistry available online (www.scadent.org) and as a CD-ROM.

Fig 1-5 Dental Color Matcher Closest match exercise.

Fig 1-6 Dental Color Matcher Matching pairs exercise: 14 . darker pairs of shade tabs successfully matched.

After the video, users are prompted to Matching pairs exercises to match 29 VITA Linearguide 3D-Master pairs (15 lighter pairs and 14 darker pairs; Fig 1-6). The subsequent Exact match exercise is identical to the initial Closest match exercise except that there is an exact match to each tab. The next step is a quiz in which users answer 12 multiple-choice questions related to the information provided in the video. After completing the program, users can fill out a survey, rate the program, and list its strengths and weaknesses. Upon request, dental professionals can obtain two continuing education hours, while all users obtain a diploma upon program completion issued by SCAD. Dental educators who want to use this program for undergraduate or postgraduate teaching or continuing education for dental students or professionals are encouraged to request a project code (by sending an email to [e-mail]), which will allow them to independently access the results for each enrolled participant.

Fig 1-7 (a) Toothguide Training Box with the associated computer program. (b) Toothguide Training Box with working area illuminated by color-corrected light.

A Contemporary Guide to Color & Shade Selection for Prosthodontics is a DVD published by the American College of Prosthodontists.¹³ It is a predominantly educational tool with 63 figures and 12 instructional videos that complement the pseudonymous text.

In the first part, general color topics are addressed: color triplet, defective color vision, color mixing, the color wheel, a description of color and the relationship between the dimensions of color, and two color notation systems: Munsell and CIELAB. The second part of the text is related to the color of human teeth, dental shade guides, and digital shade selection.

The DVD also includes detailed guidelines for visual shade selection and suggested procedures and discusses:

•Light source parameters

•Type, amount, and location of lighting

•Metamerism

•Surrounding colors

•Shade-matching distance

•Time and length of shade selection

•Patient position and involvement

•Tooth condition, including light transmission and surface characteristics (texture and gloss)

•Translucency and transparency

•Dentin and gingival shade selection

Shade verification and communication with the dental laboratory technician using diagrams and digital images are also elaborated.

Another multimedia program is the Toothguide Trainer software and Toothguide Training Box (Vita Zahnfabrik; Fig 1-7), which are parts of the color-training program.¹⁴–¹⁶ The exercises in the training software are essentially the same as those in the training box; both utilize 26 shade tabs from the Toothguide 3D-Master (Vita Zahnfabrik). The software uses the images of tabs, whereas the training box uses physical shade tabs along with color-corrected light and computer support. The program is designed in accordance with the three-step method recommended for three-dimensional shade matching (value-chroma-hue selection). A total of 4, 8, and 15 correct matches, respectively, are needed to pass steps 1 (value selection), 2 (value-chroma selection), and 3 (value-chroma-hue selection). After that, the user proceeds to 15 value-chroma-hue tasks in the final exam.

Fig 1-8 Color-training exercises, advanced set.

The book Esthetic Color Training in Dentistry (Mosby, 2004) and its supplementary color-training exercises on CD-ROM are designed to be used by dental professionals, educators, and students.¹⁷ The training program consists of an introductory set, a training set, and an advanced set. The introductory and training sets each consist of three groups of exercises that progress from easy to difficult. Each of these six different sets consists of 25 small squares and arranging sets that test shade matching based on differences in value, chroma, or hue, and, for further challenge, differences based on all possible pairs of color dimensions (value/chroma, value/hue, and chroma/hue). The advanced set (Fig 1-8) contains 15 rectangles with color differences that originate from all three color dimensions simultaneously. The software records both first and highest scores and includes a reset score option that enables repetition of the exercises or addition of other users.

It is obvious that many things have changed since the first color education and training program was administered back in 1975.¹⁸ In addition to changes related to color education and training, the entire profession has changed along the way. With the development of advanced materials, tools, and technologies and the high percentage of tooth-colored restorations, the expectations of both patients and the profession have increased. Color is one of the most significant parameters when it comes to patient satisfaction. As stated by Bergen, Color is unimportant to the physiologic success of a dental restoration, yet it could be the controlling factor in the overall acceptance by the patient.¹⁹

Conclusions

Significant advances have been made in color education and training in dentistry. New books and other types of publications—training programs on CD-ROM, online programs, or those that utilize physical shade tabs—are currently available. Based on purpose and scope, all of these publications and programs offer valuable color education and/or training. Online programs provide free access to a wide range of users (clinicians, dental technicians, dental educators, students, and researchers) seeking color education and training. Color Matching Curriculum, a half-day continuing education module, is the most recent and the most comprehensive resource for dental students and dental professionals. Knowledge and skills acquired through these programs complement the skills of dental professionals and provide an appropriate foundation for their work.

Summary

•Shade-matching results can be improved through color education and training.

•Most color education and training programs are relatively new, and unfortunately few are currently incorporated into undergraduate or graduate dental education. Therefore, the implementation of available programs and the development of new tools should be the next step in color education and training in dentistry.

References

1. Sproull RC. Color matching in dentistry. 3. Color control. J Prosthet Dent 1974;31:146–154.

2. O’Keefe KL, Strickler ER, Kerrin HK. Color and shade matching: The weak link in esthetic dentistry. Compendium 1990;11:116–120.

3. Goodkind RJ, Loupe MJ. Teaching of color in predoctoral and postdoctoral dental education in 1988. J Prosthet Dent 1992;67:713–717.

4. Okubo SR, Kanawati A, Richards MW, Childress S. Evaluation of visual and instrument shade matching. J Prosthet Dent 1998;80:642–648.

5. Paravina RD. Performance assessment of dental shade guides. J Dent 2009;37(suppl 1):e15–e20.

6. Paravina RD, O’Neill PN, Swift EJ Jr, Nathanson D, Goodacre CJ. Teaching of color in predoctoral and postdoctoral dental education in 2009. J Dent 2010;38(suppl 2):e34–e40.

7. Clary JA, Ontiveros JC, Cron SG, Paravina RD. Influence of light source, polarization, education, and training on shade matching quality. J Prosthet Dent 2016;116:91–97.

8. Ristic I, Stankovic S, Paravina RD. Influence of color education and training on shade matching skills. J Esthet Restor Dent 2016;28:287–294.

9. Society for Color and Appearance in Dentistry. Color Matching Curriculum. http://www.scadent.org/news/free-color-training . Accessed 3 June 2016.

10. International Organization for Standardization. ISO/TR 28642 Dentistry—Guidance on Color Measurement. Geneva: International Organization for Standardization, 2011.

11. Paravina RD. Dental Color Matcher: An Online Educational and Training Program for Esthetic Dentistry. http://ec2-52-53-152-188.us-west-1.compute.amazonaws.com/ . Accessed 2 December 2016.

12. Paravina RD. Color and shade matching. In: Hilton TJ, Ferracane JL, Broome I (eds.). Summitt’s Fundamentals of Operative Dentistry: A Contemporary Approach, ed 4. Chicago: Quintessence, 2013:79–93.

13. Goodacre CJ, Paravina RD, Bergen SF, Preston JD. A Contemporary Guide to Color and Shade Selection for Prosthodontists [DVD]. Chicago: American College of Prosthodontists, 2009.

14. Haddad HJ, Jakstat HA, Arnetzl G, et al. Does gender and experience influence shade matching quality? J Dent 2009;37 (suppl 1):e40–e44.

15. Corcodel N, Karatzogiannis E, Rammelsberg P, Hassel AJ. Evaluation of two different approaches to learning shade matching in dentistry. Acta Odontol Scand 2012;70:83–88.

16. Olms C, Jakstat H. Learning shade differentiation using Toothguide Trainer and Toothguide Training Box: A longitudinal study with dental students. J Dent Educ 2016;80:183–190.

17. Paravina RD, Powers JM. Esthetic Color Training in Dentistry. St Louis: Mosby, 2004.

18. Bergen SF. Color Education for the Dental Profession [thesis]. New York: New York University College of Dentistry, 1975.

19. Bergen SF. Color in esthetics. N Y State Dent J 1985;51:470–471.

COLOR THEORY

IN THIS CHAPTER:

•The physics of color

•Color perception

•Color mixing

•Color in dentistry

Fig 2-1 The wavelengths of light refl ect off the object (a rose), resulting in the perception of color (pink) by the viewer.

Fig 2-2 A red apple. Its specific color description is subjective and debatable, stemming from an emotional or visceral response.

Many have long pondered the question: If a tree falls in the woods and there is no one there to hear it, does it make a sound? In color theory the question becomes: If the petals of a rose are pink and there is no one there to view them, are they actually pink? According to color theorists, the answer is no. The reason for this surprising answer is that in order for a color to exist, there needs to be an interaction between three elements: light, an object, and a viewer (Fig 2-1). If all three elements are not present, color as we know it does not exist.

Color appeals to the visceral and emotional senses. Color is personal; individuals with normal color vision will view the same object similarly, but not exactly the same. Take, for example, the apple shown in Fig 2-2. Most would define its color as red; others might take it a step further and describe it as cranberry red or vibrant ruby red. It is often difficult to come to a consensus based on visual assessment alone. There are numerous factors that influence an individual’s color perception, including lighting conditions, background effects, color blindness, binocular differences, eye fatigue, age, and other physiologic factors (see chapter 3). But even in the absence of these physical considerations, each observer will interpret color differently based on his or her past experiences with color and resulting color references. Each individual also verbally defines an object’s color differently.¹–⁹

However, there are quantifiable aspects of color that are important for the dental practitioner to understand. Basic knowledge of how color is perceived and reproduced will aid the clinician in evaluating and matching shades in the dental practice.

The Physics of Color

Although color is generally perceived as an art form, there is a true science behind color theory. Isaac Newton was the first to break down the physics of color. He found that a beam of white light could be separated into component colors, or wavelengths, by passing it through a prism (Fig 2-3). Newton described the resulting continuous series of colors as a spectrum and named these colors in the following order: red, orange, yellow, green, blue, indigo, and violet, as represented by the commonly used mnemonic association Roy G. Biv. These wavelengths are perceived by the three types of color receptors (called L-, M-, and S-cones) in the human