Our ability to mimic nature in the fabrication of esthetic restorations is a difficult process.1,2 Teeth are not monochromatic and to simply describe and subsequently prescribe a single hue or shade to the technician can readily fall short of providing the patient with a suitably matched restoration.3 Our abilities to accurately interpret what we see is individual and subjective,4 as well as our ability to process this interpretation into a format that is understandable to someone else. The tools for both diagnosing and communicating tooth appearance are not as standardized as one might desire;5 and the entire process can be quite vulnerable to error.
Shade scanners, digital photography, new ceramics, and other advances would be sufficient for success if this process was 100 percent science, but it is not. The human element is key to esthetic success because factors of appearance depend upon artistry in diagnosis, prescription, and fabrication.6 With this in mind, predictability rather than simplicity needs to be the focus. A step-by-step approach using reliable systems that provide repeatable outcomes makes the process less difficult for achieving success.7
Basic to this discussion is that teeth are not monochromatic.8 In fact, the polychromatic presentation of most teeth is even more complex when one considers the multitude of appearance attributes that often present in nature other than shade. These attributes range from translucency format and degree to hypocalcifications, crack lines, surface anatomy, et al. While a complete diagnosis and prescription must elaborate shade in the cervical, body, and incisal regions of the tooth, there must be denotation of these alternate appearance attributes to realistically mimic the appearance of the tooth.9
The first step is to optimize conditions for observing the dentition. The immediate environment around the patient should be as neutral as possible10 to include removal of any lipstick and/or shielding the viewing area from brightly colored clothing or other distractions. Natural or color-corrected light11 is more desirable and when using an artificial light source, a full-spectrum versus wide spectrum fluorescent lamp is more accurate. The patient bib is ideally a neutral color such as gray or a color that allows the eye to “reset” such as blue. More than one tab should be viewed initially and those not matching are eliminated from the selection process. The shade tab and tooth should be viewed in the same plane; and in short intervals insofar as our eyes can fatique rather quickly. Generally, the first choice is most accurate, however this is not a rule and beginning the process anew with adequate eye rest is acceptable. It is preferable to take shades at the beginning of the appointment when the teeth are hydrated and it sometimes helps to wet the shade tab for comparison to highly textured teeth.12 Assessing value is critical during the shade taking process and is preferably the first determination in the diagnostic process.13
The demand for putting information into a format that is understandable by someone else is paramount in dentist-technician communication.14 Obviously, the more information available to the technician, the likelihood of the dentist getting-back-what-he(she)- asked-for is much greater.
General considerations that will assist in setting the stage for success are outlined in Table 1.
The second step in the process needs to be governed by as much standardization as possible. That is to say — any words, coding, schematics, images, etc. must always mean the same thing to both the dentist and technician. Much like calibrating a computer monitor, the language that is used between dentist and technician needs to be calibrated for greater exactness.15 A little more intense, a little less intense when referring to translucency or a wash, a veil when referring to hypocalcifications are descriptions that leave a good deal of room for subjective interpretation and provide for much less predictable repetition. In many instances, dentists believe that the technician will make up for insufficient information from the dental office with artistic abilities gained from training and experience. The disappointment that can follow is a testament to how this belief can be counterproductive. Teams (dentist and technician) that work together for sufficient time may develop a sense of what he or she expects and/or will do, but this is not foolproof, sometimes lacking in consistency and not necessarily reproducible if one or the other is “out-of-the-loop”. Thus, referencing reliable standards supports greater predictability as well as reducing the need to re-invent-the-wheel for each case.
Following a prescribed sequence in the diagnosis of tooth appearance (Table 2) will enhance the information to be provided to the technician. This process will ensure that all subtle, as well as overt features will be identified and communicated.
The laboratory prescription must be a specific, comprehensive, and understandable blueprint for the final restoration rather than what might seem like hints (i.e. PVC; A-2; hypo) with the assumption the technician will fill in the missing information.16
The third step supporting a positive outcome is the selection and use of tools that work well for each individual (Table 3). This sounds non-specific, but in reality there is no universal tool or specific system that will be instantly successful without a minimum amount of practice and experience17 while there are criterion for what might be considered ideal. These criterion would include being user-friendly, reliable as an accurate reference for information, and having a standardized content so that a solution is at hand for any situation within its scope. These attributes, in combination with following reliable protocols is of utmost importance.
Having an understanding of our limitations sheds light on the extent of our capabilities and helps to define realistic and realizable expectations.
Schematics may be used to delineate tooth appearance and can offer detailed descriptions if properly constructed. As with any other communication, the accuracy of the information provided directly affects the restoration that will be fabricated. This endeavor can be very fulfilling for those who are artistically inclined, although there are time demands to adequately express what is necessary.
The communication of shade rests primarily with tab guides and shade scanners for ‘absolute’ reference; and photography for ‘relative’ reference. Tab guides and scanners enable us to specify what the shade is, whereas photography — in many ways — gives more insight into what it is not. While shade tabs are an assumed standard for referencing shade, there are subtle variations in manufactured guides with not all guides of a specific system matching one another, as well as variations within individual guides.18 The materials tabs are constructed with are often not the material being represented (i.e. resin guides depicting porcelain shades). And, there are differences in standardization with the arrangement of some guides being based on hue and some based on value.
Scanners offer a seemingly turn-key means of ascertaining tooth shade with subsequent scanning of the restoration for verification; and purport to describe other features as well. Statistically, scanners fulfill this expectation more often than not — 60-70% — as related to the author by numerous technicians and practitioners. Some practitioners and laboratories express complete satisfaction with the use of scanners,19 while more individuals anticipate improvements in the technology that will increase reliability and justify the expenditure in light of the 46-57% success rate that can be achieved using tab guides.20
Photography is excellent for depicting contours, relationships of the teeth to the smile, and relationships of the smile to the face. For value, black and white photography provides good reference and
color photography is an asset to determining shade based upon relative comparisons. Nuances of tooth appearance such as translucency, hypocalcifications, crack lines, or surface anatomy — though reproducible — are not routinely captured with accuracy. In reference to capturing features of tooth appearance, photography can be technique sensitive; most often requiring multiple exposures of the observed feature with varying lighting, angles of exposure, and exposure settings. Then, there is inherent loss with the transfer of this information, specifically when there is a media change in output ; and it is common for this change to also have an impact on our perceptions — an example of which is to photograph a shade tab; print the image; then compare the printed image to the shade tab finding that the two do not match. Additionally, one can view the same image on a monitor and in printed form realizing a perceived difference in appearance.
Tooth appearance is a composite of other elements aside from considerations of shade, chroma, and value; translucency, hypocalcifications, and surface anatomy being the most dominant features that may have a significant impact on the final restoration(s). These additional features in tooth appearance are finite and essentially the same in quality and character from one person to another. Differences between individual circumstances are a matter of how these respective elements layer and distribute to form a composite presentation. Adding these elements to the final restoration is necessary to truly replicate the natural appearances we are observing; and to create a structure that has light interactions similar to tooth structure. The variety of observable coloration and physical detail that exists in teeth is a function of light interactions directly on the tooth as well as within the tooth. By including these elements — in part or in whole — light reflection and other light interactions can be influenced enabling a more life-like appearance.
Communicating appearance attributes of teeth other than shade presents difficulty because of what has already been related — scanners and photography are not always reliable for recording these features. Added difficulties arise when high resolution digital images are printed for the technician on conventional bond paper versus photographic quality paper, or one’s visual memory errantly confirms that an electronic or printed image accurately displays what was seen clinically when, in fact, it does not.
The LADDER (Laboratory And Dentist Digitally Enhanced Reference) is a guide for diagnosing and communicating appearance attributes other than shade that includes translucency format, degree of translucency, translucency hue, hypocalcifications, brown discolorations, crack lines, surface anatomy, and variations. Standardization is one key to its usefulness inasmuch as all guides are identical and the features within images are unchanging. Images in the guide are the same dimension with the same background to eliminate distraction — encoded individually and within categories. While photographs of actual teeth, the images have been enhanced to compensate for loss of detail that would result from taking them to print, supporting perception of these features exactly as they would appear clinically. Subjective interpretations of written words, interpreting schematics, or receiving images with insufficient or compromised information are eliminated.
As previously described, the quality and character of appearance attributes in teeth are essentially the same from one individual to another while differences are based upon location and degree of intensity. The dentist or auxiliary denotes a specific feature(s), using coding that is respective to the feature(s), and maps the location on accompanying Rx forms; while the technician views the identical image(s) during fabrication.21 Thus, the dental office and technician possess a user-friendly guide that is accurate and universal. Rather than re-establishing parameters for each patient, respective features can be selected from the vast array of images that are displayed and apply those that are appropriate to each patient. On-going success is enhanced with continued use as the dental team and laboratory gain familiarity with the features. Although shade is assessed independently, the diagnostic regimen of The LADDER helps to eliminate the distraction features can create and shade-taking improves significantly; prompting the clinician and/or auxiliary to more accurately describe tooth appearance in total.
CASE 1 — TOOTH #’S 6, 7, 10, 11
In the first case, four full zirconium crowns were placed on tooth #’s 6, 7, 10, & 11 to compensate for space discrepancies following orthodontic treatment. A waxed study model was sent to the laboratory for outline form and contour reference. There were no pre-operative photographs included with records sent to the laboratory (Fig. 1).
The prescription for these restorations (Fig. 2) detailed shade using the 3D Vitapan shade guide; and all other appearance attributes necessary for matching the adjacent dentition. The translucency format was indicated using the desired image from The LADDER (Fig. 3); then the degree of translucency (Fig. 4) which is better viewed with the LADDER image upside down.
In order to create more light interaction in the incisal 1/3, diffuse surface hypocalcification –DSH (T) (Fig. 5) was prescribed in areas mapped on the LADDER Rx. This feature is not seen from conversational distance, yet adds to the life-like appearance of the restorations. The surface anatomy of the existing dentition is rather linear, so SA-1 (Fig. 6) was selected. Additionally, the value and chroma pages in The LADDER were referenced and coding for these attributes was included on the LADDER Rx.
CASE 2 – TOOTH #’S 4-13
Porcelain laminate veneers were placed on tooth #’s 4-9 and #’s 12 & 13 while a 3-unit porcelain-to-gold bridge was placed on tooth #’s 9-11, replacing tooth #10 (Fig. 7). The shade was prescribed using a Classic Vitapan shade guide and this was noted on the Rx (Fig. 8) along with the translucency format (Fig. 3) and degree of translucency (Fig. 4).
Again, to create more light interaction in the incisal 1/3 of the restorations, an additional feature was requested — diffuse sub-surface hypocalcification coded as DDBH(T) (Fig. 9). The desired location of this attribute was mapped on the LADDER Rx in the characterization outline. Then the surface anatomy was prescribed (Fig. 10) and the value and chroma images referenced in The LADDER to assign the appropriate code.
A 1:1 photograph of tooth #’s 7-10 (Fig. 11) illustrates the more life-like appearance enabled by these subtle additions of appearance attributes, along with ovation of the pontic site tooth #10.
SUMMARY
Our goal is to accurately diagnose and communicate a desired appearance that will allow the technician sufficient information in order to fabricate a truly esthetic restoration. The technician, in turn, must possess the technical and artistic skills to create an esthetic restoration with high clinical acceptability and with limited, or no fabrication guidance.22
This process needs to be orderly, repeatable, and complete so that each task along the way can be mastered and refined with ongoing experience. Integral to this pursuit is an examination of what is relative and subjective with our tools, techniques, and communications; so that we can strive toward what is absolute and objective.
The functional aspects of restorative dentistry are appropriately rooted in science, while mimicking nature for esthetics is not a simple endeavor and requires attention, skill, and artistry. It is a matter of blending subjective interpretation into a science-based application. Technology supports the process and one must keep in mind that it enables short-steps more than short-cuts.
Dr. Weinstein maintains a private practice in Greenwood Village, Colorado with emphasis on ad
vanced cosmetic treatment and has lectured both nationally and internationally on esthetic treatments. He is an Accredited Member of the American Academy of Cosmetic Dentistry and Fellow of the International Academy of Dental Facial Esthetics. He can be reached at info@4theladder.com.
Oral Health welcomes this original article.
TABLE 1
Rules of 3
Optimization, Standardization, and Armamentarium
– Optimize conditions for observing the dentition.
– Standardize protocols.
– Select and use tools that you can master.
Diagnosis, Communication, Fabrication
– Accurately delineate shade and features.
– Prescribe in a mutually understood format.
– Build restoration(s) to the prescription.
Hue, Value, Chroma
– These attributes are interdependent. The overall appearance of teeth cannot be described by shade alone.
Cervical, Middle, Incisal
– Assign shade and features for each 1/3 of the tooth.
Translucency, Hypocalcifications, Surface Anatomy
The 3 most impactful features in tooth presentation.
– Recognize & prescribe the format, degree, and hue of translucency.
– Assess hypocalcifications — the most common distraction when taking shade is generalized diffuse hypocalcification.
– Specify surface anatomy because models & photographs are not always accurate for this attribute.
TABLE 2
The diagnostic sequence
Determine and prescribe:
1. translucency format
2. degree of translucency
3. translucency hue
4. existence and/or need for characterizations
– hypocalcifications
– brown discolorations
– crack lines
– any variations that may exist
5. surface anatomy
6. value, chroma, and hue (shade)
Once the distraction of features is eliminated, shade becomes more readily determined.
TABLE 3
SHADE Diagnosis & Communication
Shade guides
Vita Lumin (Vita) www.vident.com
Vita 3D Vitapan (Vita) www.vident.com
Chromascope (Ivoclar Vivadent) www.ivoclarvivadent.com
Vintage Halo (Shofu) www.shofu.com
Scanners
– Clearmatch — Software, digital color image analysis www.clearmatch.com
– ShadeEye (Shofu) colorimeter www.shofu.com
– Shadescan (Cynovad) — digital color imaging www.cynovad.com
– Shadevision (X-Rite) digital image with digital colorimetric analysis www.xrite.com
– Vita EasyShade (Vident) spectrophotometer www.vident.com
– Spetroshade (MHT International) digital imaging and spectrophotometric analysis www.mht.com
Cameras (Photomed.net)
Canon EOS Rebel Xti
Canon EOS 30D
Canon EOS 5D
Nikon D40
Nikon D40X
Nikon D80
Nikon D200
Appearance Attributes — Diagnosis & Communication
– Photography
– Scanners
– The LADDER www.4theladder.com (Laboratory and Dentist Digitally Enhanced Reference)
REFERENCES
1.Kahng L, Wegandt F. Shade Matching for a Single Tooth Using an All-Ceramic Crown: Laboratory Protocol. Prac Proced Aesthet Dent 2004;18(7): 425-429
2.Fondriest J. Shade Matching in Restorative Dentistry: The Science and Strategies. Int J of Perio & Rest Dent 2003;23(5):467-477
3.Behle C. Shade Selection Techniques: Part One-Tools for Effective Communication. Prac Proced Aesthet Dent. September 2001;13(7):536.
4.Carsten DL. Successful Shade Matching-What does it take?. Compendium March 2003;24(3):175-85
5.Ferreira D, Monard LAG. Measurement of Spectral Reflectance and Colorimeteric Properties of Shade Guides. J Dent Assoc Safr 1991;46:63-65
6.Derbabian K, et al. The Science of Communicating the Art of Esthetic Dentistry, Part III: Precise Shade Communication. J Esthet Restor Dent 2001; 13:154-162
7.Hassel AJ, Koke U, Schmitter M, Beck J, Rammelsberg P. Clinical effect of different shade guide systems on the tooth shades of ceramic-veneered restorations. Int J Prosthodont 2005, 18(5):422-6
8.O’Brien WJ, Hemmendinger H, Boenke KM, Linger JB, Groh CL. Color distribution of three regions of extracted human teeth. Dent Mater 1997 May;13 (3):179-85
9.Sorensen JA. Torres TJ. Improved color matching of metal-ceramic restorations. Part II: procedures for visual communication. J Prosthet Dent 1987; 58:669-667
10.Jun SK. Shade Matching and Communication In Conjunction with Segmental Porcelain Buildup. Pract Proced Aesthet Dent 1999;11(4):457-464
11.Northrup Don. The Importance of Light in Aesthetic Dentistry. Aesthet Dent 2006 Summer:18-20
12.Miller A, Long J, Cole J, Staffanau R. Shade Selection and Laboratory Communication. Quint Int 1993;24(5):305-309
13.Vollman M. Vitapan 3D-Master: theory and practice. Quintessence Dent Techno 1999;22:43-53
14.Gillis, RD Jr. Communicating with dental laboratories. Dent Abstr 1997;42(4):166-167
15.Zammarieh, E. Dentists are from “Jupiter” and Technicians are from “Mercury”: Simple Steps on How to Prevent Remakes. Contemp Esthet and Rest Pract September 2003:70-73
16.Samaras, CD. Shade Matching/Mapping Technology for the Everyday Dentist. Contemp Esthet and Rest Pract January 2004:52-54
17.Gillis, RD Jr. Communicating with dental laboratories. Dent Abstr 1997;42(4):166-167
18.Hasegawa A, Ikeda I, Kawaguchi S Color and translucency of in vivo natural central incisors. J Prosthet Dent 2000 Apr; 83(4):418-23
19.Horn DJ, Bulan-Brady J, Hicks, ML. Sphere spectrophotometer versus Human Evaluation of Tooth Shade. J Endo 1998 Dec;24(12):786-790
20.Wee AG, Kang EY, Johnston WM, Seghi RR. Evaluating Porcelain Color Match of Different Porcelain Shade-Matching Systems. J of Esthet Dent 2000;12(5):271-280
21.O’Keefe KL, Strickler ER, Kerrin HK. Color and Shade Matching The Weak Link in Esthetic Dentistry. Compen Contin Educ Dent 1990;11(2):116-120
22.Chu SJ, Tarnow DP. Digital Shade Analysis and Verification: A Case Report and Discussion. Prac Proced Aesthet Dent 2001;13(2):129-136.
