Clinical Steps to Predictable Color Management in Aesthetic Restorative Dentistry

The shade matching of a restoration is the critical final step in aesthetic restorative dentistry once morphology and occlusion are addressed. This article describes a seven-step approach to successful shade matching: patient and tooth evaluation, image capture and shade analysis, communication, interpretation, fabrication, verification, and placement of restoration. A step-by-step protocol to shade matching is comprehensively outlined through a case study using a combination of technology-based instrumentation, conventional techniques, and reference photography.

The shade matching of a restoration is the critical final step in aesthetic restorative dentistry once morphology and occlusion are addressed. The variables in the dental treatment room and human error are recognized obstacles first divulged by Dr. Jack Preston at USC Dental School. Color is both a science and an art, and can often be difficult to measure.

Conventional shade methods and technology by itself have limitations, because technicians require more visual information to interpret shade information. Advances in technology have greatly elevated the likelihood of a clinically acceptable shade match through accurate shade analysis, if properly performed. After much research and clinical evaluation, this article addresses a culmination of knowledge that embodies how the author perceives predictable shade matching.

A step-by-step protocol to shade matching is comprehensively outlined through a case study using a combination of technology-based instrumentation, conventional techniques (ie, shade tabs), and reference photography: a wonderful way for predictable shade matching that, if performed properly, can limit costly remakes.

Predictable shade matching protocol

Step 1: evaluation

This phase of treatment may be the most clinically significant because proper shade matching is directly dependent on the tooth type (ie, whether the tooth is high or low in translucency) ( Fig. 1 ).

Fig. 1
The central incisor teeth represented in the photograph on the left are low in translucency and high in opacity. Note the lack of translucency throughout the tooth structure. Matching these teeth is best served with metal-ceramic restorations or computer aided design-computer aided manufacturing (CAD-CAM)–based ceramics. The central incisor teeth on the right are higher in translucency. Materials selection and restoration type for these teeth may comprise the following: all-ceramic refractory cast or platinum foil veneer or crown; leucite-reinforced pressable ceramics; or a porcelain butt margin CAD-CAM–based ceramic restoration, such as zirconia.

Preoperative evaluation affects material selection because the choices of materials that can be used for the definitive restoration (ie, metal-ceramic or high-strength computer aided design-computer aided manufacturing (CAD-CAM)–based ceramics, such as alumina or zirconia [ Fig. 2 ]) ultimately dictate the tooth preparation design ( Fig. 3 ). The stump shade of the tooth must be taken into consideration because it may influence the value, chroma, and hue of the final restoration if a translucent or semitranslucent material is used ( Fig. 4 ).

Fig. 2
High-strength CAD-CAM materials are available in various types of ceramic (ie, alumina and zirconia) to satisfy the strength and aesthetic requirements anywhere in the mouth. They possess light transmission qualities greater than that of metal-ceramic restorations. Optical properties vary; familiarity with these materials is a must because CAD-CAM has become increasingly popular and widely accepted among dentists and laboratory technicians alike.

Fig. 3
Tooth preparation design may take many forms and is primarily dependent on the material chosen and collar design for the final restoration. A slight chamfer preparation ( left A ) requires a metal collar design because there is minimal reduction in the cervical one third of the tooth. With an angular shoulder (135-degree) preparation ( right A; left B ) or full rounded shoulder ( right B ), a zero metal collar or ceramic butt margin, respectively, can be selected because greater tooth is reduced in the gingival one third. CAD-CAM–based restorations or a pressed leucite-reinforced material can be selected with the equivalent preparation designs previously mentioned for the same reason.

Fig. 4
The stump shade of the tooth must be taken into consideration because it may influence the value, chroma, and hue of the final restoration if a translucent or semi-translucent material is used.

Questions to consider during the preoperative patient evaluation include the following:

  • 1.

    Is there significant variation of shade from gingival, to body, to incisal?

  • 2.

    Are there any characterizations or effects in the tooth?

  • 3.

    Can the patient’s teeth be categorized as high in translucency or high in opacity?

  • 4.

    Can materials selection affect the final aesthetic outcome of the restoration?

After those questions have been addressed a treatment plan can be developed, and the clinician can determine the ideal material selection and preparation for the restoration.

Step 2: image capture and shade analysis

One way to analyze the shade is to use technology (SpectroShade Micro, MHT S.P.A., Milan, Italy) ( Fig. 5 ), because it is the least influenced by contrast effects and visual discrepancies associated with improper lighting. Technology requires image capture ( Fig. 6 ) or image acquisition. Once the images are brought into the database and stored, they can then be analyzed for shade ( Figs. 7 and 8 ). Today’s technology streamlines shade analysis by indicating which shade tabs the clinician should select for reference photography (shade communication).

Fig. 5
Spectrophotometers measure and record the amount of visible radiant energy reflected by the teeth one wavelength at a time for each hue, value, and chroma present in the entire visible spectrum. It uses reflectance technology because it only calculates the quantity and quality of light that is not absorbed by the measured tooth. Present spectrophotometers used in dentistry illuminate the teeth at a 45-degree angle of incidence to the object to eliminate reflectance glare and thereby distortion of the image. The reflected light from the image is captured at a zero-degree angle of incidence. A specific and unique fingerprint of the image is then recorded at intervals of 10 nm throughout the whole visible light spectrum (400–800 nm).

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Jun 15, 2016 | Posted by in Esthetic Dentristry | Comments Off on Clinical Steps to Predictable Color Management in Aesthetic Restorative Dentistry
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