One of the most challenging procedures in restorative dentistry is
matching the shade of a single anterior tooth. Lighting, environment, and
perception must be considered during the taking of shades to ensure a proper
match.1 Restorative team members must use identical standards of
measurement and communicate about shade and color. Failure to communicate risks
a mismatched restoration and unaesthetic results.2 This article
highlights a method of shade and color communication used in aesthetic ceramic
Lighting influences shade perception. Color is viewed differently
in varying levels of sunlight and the time of day that shade is taken. Orange
colors prevail in morning, and blue is dominant at midday.3
"True color" is determined when the sun is in its most northern
location. Therefore, it is imperative that operatory and laboratory
environments are as uniform as possible.
Color is perceived when light reflected from an object strikes an
observer's eye in different wavelengths3; if there is insufficient
light, colors with small wavelengths (ie, violet, indigo, blue) cannot be
accurately perceived. Sufficient lighting is approximately 5500 K,4.
Eight (1.2 m) color-corrected lights per operatory (2.4 m (3.1 m) provide
adequate light, allowing for an optimal shade match.5 A
color-viewing light selector can be used to determine when a room has been lit
at 5500 K.
Natural light, often absent in operatories and laboratories, is an
advantage in color matching, since the environment can be controlled
artificially.6 Regulate room color to prevent shade
misinterpretation. A neutral gray room illuminated by color-corrected
fluorescent bulbs is ideal since gray is a combination of all primary and
secondary colors of the light spectrum 6.
Patients should be “neturalized” with a gray bib and should not be
wearing lipstick. After establishing the environment, the technical process of
shade taking can begin.
To evaluate a shade, the clinician determines the hue of the
patient's dentition and measures its intensity with a shade tab. However, the
clinician must determine an appropriate match independent of such guides as
this method is often inaccurate.
Cone cells on the surface of the retina become fatigued when a
color is viewed for an extended period, thus decreasing the acuity of the
signals relayed to the brain. 3 To prevent fatigue, the patient
should wear a blue bib during shade taking since the basic tooth shade is
yellow-orange to red-orange. As the clinician views the patient's mouth, the
eye muscle becomes fatigued to orange and alters the accurate perception of
shade. The blue bib recharges the sensation of orange in the cone cells and
corrects the inaccurate shade perception. It also must be considered that teeth
- particularly aged teeth - have a glossy surface that absorbs the shade of any
color placed in close proximity.
Shade should be taken prior to preparation for accuracy as the
adjacent teeth become dehydrated during this process. Patients should sit with
their chins tilted down to minimize light reflection from the tooth surface.
Next, place the shade selection system below the patient's closed mouth to
ensure that all elements will be equally affected by the surroundings, time of
day, or contrasting colors. Finally, manipulate the shade guide to determine
the hue and intensity of the color. The closest shade should be selected and
modified as necessary.
Alternatively, the shade guide can be placed by value rather than
order to improve matching.7 Since value can only be perceived by a
squinting viewer,5 this may provide a third means of determining
Next, use a second color system to verify the basic shade
selection. This system has individual tabs for each aspect of the tooth (eg,
dentin, enamel, incisal) permitting the layering of porcelain materials
resulting in an accurate shade match (Figure 1). Determine if any color
difference exists between the crown and the root (if it is exposed). The
gingival region may be warmer or more chromatic than the rest of the tooth. Due
to its natural curvature, the body of a tooth generally has a brighter value
than its gingival or incisal aspect. Occasionally, a white band can be created
across the surface of a tooth to increase its value.
Numerous internal characterizations are present in the incisal aspect
of a tooth. In adolescents, the mamelon structure may be intact, adding a
challenge in color matching. Older patients may have worn incisal edges, which
exposes the dentin layer. As this layer is exposed, the resulting discoloration
between the dentin and enamel layer allows multiple colors to be observed in
the incisal region. Examine this area with a mirror to determine all the colors
in the incisal aspect.
When a difference exists between the color of the gingival and
incisal layers, it is common to mask the former while taking the shade of the
latter (and vice versa). The shade guide used to measure these colors should be
performed with a hemostat to prevent color misperception.
After selecting a basic shade, use an overlay or underlay of
colored translucent porcelain for a shade match. Additionally, accurate
photographs can be used to communicate color. Slightly angle a camera to
minimize light reflection that can distort color. Place the shade guide
adjacent to the corresponding tooth and similarly angled. This ensures that the
correct information is exchanged between the members of the restorative team,
who should always utilize identical shade selection systems.
Stained teeth can be restored when shade is recorded and described
to the technician. Stain the restoration in an environment with corrected,
neutral light so that the crown will match the adjacent teeth (Figure 2). If
the basic shade does not precisely match the shade tab, all varying colorations
applied to the restoration will be fruitless since it was initially
(Continued from page 1 )
Several porcelains require additional staining to achieve a match.
In such procedures, the underlying optical characteristics of the tooth or
restoration are masked by metallic-oxide stains, which demonstrate a
monochromatic appearance. Perform staining in color-corrected light to prevent
mismatched shades postoperatively. The fluorescence of porcelain materials
cause an iridescent effect that reacts to and reflects light as a natural tooth
(Figure 3).8 A material may prove inadequate if multiple bakes are
required to modify the colors and the anatomy of the tooth. The product must
maintain morphology and color after repeated firing.
For optimal results, maintain communication between the patient,
clinician, and laboratory technician. Computer imaging can be used to provide
patients with a picture of the anticipated restoration. However, a diagnostic
waxup can be more accurate. (Figures 4-5-6-7). After approval of the
restorations, the definitive restorations can be fabricated and cemented into
their final position (Figures 8 and 9).
A 33-year-old patient presented restoration of preexisting
laminate veneers that had discolored. (Figure 10). A waxup was fabricated and
seated intraorally for approval (Figure 11). Softening of the internal
characterization and lightening were requested. A matrix was fabricated and
duplicated in porcelain. The waxup permitted communication with the patient and
allowed the restorations to be fabricated individually (Figure 12).
For natural looking restorations, light had to be diffused, and
the illusion of depth had to be created. The initial opaque layer was placed
unevenly to scatter the light. A white opacious dentin layer was subsequently
applied to re-create value lost as the layering progressed. During the layering
process, indentations were placed (Figure 13) and filled with clear translucent
material to scatter and trap the light (Figure 14). The dentin layer was built
up to the exact size and contour of the definitive restorations and cut back as
necessary (Figure 15).
Next, the "fingerlike" mamelon structure was created by
painting internal stains were painted on the side wall to establish a dynamic
characterization. Spaces were filled with alternating variations of colored
incisal powders (Figure 16), to compensate for future shrinkage. Additional
internal characterizations were then developed.
A bright incisal was utilized to highlight the line angle (Figure 17). The upper two thirds of the tooth were covered with translucent powders of
varying colors using the lateral segmentation buildup technique.6,9,10
The enamel crack line was achieved by painting the side wall of the translucent
porcelain with a colored stain. Once the buildup had been performed, the
translucent layer was completed.
To compensate for shrinkage during the initial firing (Figure 18),
an auxiliary layer of colored porcelain material was added (Figure 19)
following each firing until completion (Figures 20-21-22). Matching the
surface texture and luster were also rendered. Consequently, grinding and
polishing were accomplished until the full-coverage restorations had been
completed, seated, and cemented (Figures 23-24-25).
Fabrication of natural appearing aesthetic restorations depends on
proper communication and understanding the methods used to take and match
shades. This article highlights factors that influence proper shade and color
determination. In addition, it details communication methods between the
members of the restorative team and demonstrates the use of such techniques
during the segmental buildup of porcelain restorations.
*Laboratory technician, Bay Dental Laboratory, Monterey, CA.
- Miller A, Long J, Cole J, Staffanou R.
Shade selection and laboratory communication. Quint Int 1993;24(5):305-309.
- Muia PJ. Esthetic Restorations:
Improved Dentist-Laboratory Communication. Carol Stream, IL:
Quintessence Publishing, 1993.
- Yamamoto M. Metal-Ceramics. Carol Stream, IL:
Quintessence Publishing, 1985.
- Touati B, Miara P, Nathanson D.
Esthetic Dentistry & Ceramic Restorations. London, UK:
Martin Dunitz, 1999.
- Spear F. Aesthetic communication. Las Vegas, NV: ADA Conference 1985.
- Ubassy G. Shape and Color. Carol Stream, IL:
Quintessence Publishing, 1993.
- 3D-Master, Vident, Brea, CA.
- McLaren EA. Luminescent veneers. J
Esthet Dent 1997;9(1):3-12.
- Aiba N. Fabrication of custom-made
ceramic restorations using Willi Geller's Technique. Quint Dent Technol
- McLaren EA. The skeleton buildup
technique: A systemic approach to the three-dimensional control of shade and
shape. Pract Periodont Aesthet Dent 1998;10(5):587-597.