A Practical Esthetic Solution to Challenging Clinical Situations
Composite metal structure and composition of the coping provide esthetics that rival all-ceramics, high strength factors, and protect against periodontal disease.
In this rapidly changing world of new technologies and materials, established tried-and-true systems are often overlooked, as many believe options that are not considered “cutting edge” may be outdated or inferior. This attitude could not be further from the truth and can often lead practitioners past the best solution for the restorative challenge being faced. With the tremendous number of restorative materials and systems available today, it is important to try to understand each material’s strengths and weaknesses in order to confidently make educated decisions as to the best material choices for any given restorative challenge.
Captek™ (Argen Corporation, www.captek.com) is a very unique substrate for porcelain-fused-to-metal (PFM) restorations that offers great benefits in esthetics, versatility, strength, and health. The Captek technology is, by definition, a “metal composite” where high-purity gold is reinforced with an internal skeleton of uniquely prepared hard particles of platinum/palladium. First introduced in the literature in 1995,1 Captek has undergone a continual and dramatic evolution, resulting most recently in the development of the higher-strength, super-thin Captek Nano line of materials.2 By using nanoparticle technology and manufacturing, the density of the reinforcing particles is increased over 100% from the original Captek. The engineering of the Captek Nano yields increased physical properties in thinner dimensions with slightly reduced gold content. This same advanced nanotechnology has also resulted in improved companion products that achieve a more powerful porcelain bond, are user friendly for the laboratory to build collars and coping support structures, and provide high fracture resistance.3 The Captek Nano system is also indicated for longer-span bridges that include up to two consecutive pontics and implant-supported crowns and bridges.
Because of its unique structure and composition, Captek Nano is able to provide a super-thin (0.20 mm) high gold substrate (83%) that does not oxidize,4 lose its bright gold appearance, or create darkness at the margin. Additionally, the high-purity gold—when supported internally with the unique particle structure—is clinically proven to reduce harmful bacteria and plaque surrounding restored teeth.5 With all of these attributes, it is possible to achieve esthetics that rival all-ceramics, achieve high strength factors, enable clinicians to choose their preferred margin preparation6—traditionally cement or bond—and provide a restoration that encourages health with high protective potential from caries and/or periodontal disease.
Even though some might be aware of the esthetic potential that Captek offers, in esthetic situations, dentists often still default to all-ceramics first. Transparent all-ceramics do offer high esthetic potential, but they are contraindicated in situations where the underlying tooth structure is not ideal, as often is the case for non-vital or discolored teeth.7 This can present quite a dilemma when an otherwise straightforward all-ceramic esthetic case is complicated when one or more teeth are dark, missing, or compromised—requiring bridgework—or extra protection is necessary due to intrasulcular margin position and periodontal or other systemic health concerns.8 Perhaps there is just a need for extra strength due to high-risk occlusion or posterior restorations. As demonstrated in the two cases presented, Captek Nano was a successful restorative option and offered an esthetic and functional solution to the clinical challenges.
Case 1—Management of Dark Preparations
In this case, patient was very dissatisfied with the pre-existing pressed ceramic crowns on the two centrals as well as the composite veneer on right lateral, and also wished to lengthen the left lateral. The case was originally prescribed for full-coverage lithium-disilicate crowns on the centrals with thin lithium-disilicate veneers (e.max®, Ivoclar Vivadent, www.ivoclarvivadent.com) on the two laterals (Figure 1). The obvious challenge was not just the dark preparations on the centrals, but the fact that they were two different colors (Figure 2). In addition, the roots were different in width, creating a contour/shape challenge. The situation was further complicated by the fact that the laterals were minimally prepared facially for thin veneers, while the centrals would be thicker crowns.
It is commonly thought that the solution to a dark substrate is to simply prepare more aggressively, creating more room to mask the darkness. This approach can certainly help, but it is not a total solution because the underlying color—which can also change over time—can still show through, even with aggressive preparation. This situation is depicted in the second case. When the decision is made to restore with a more opaque ceramic material, the challenge then becomes how to control the ceramic layering so as to re-establish the vitality of the crown and create a natural value and appearance of translucency. So, on the one hand, metal-free restorations can easily be too transparent, resulting in a gray or low-value appearance, while on the other hand, it is very common—especially in the cervical margin area—for the more opaque zirconia products to look overly bright and lacking in vitality.9
In the situation shown, after consultation with the doctor about the esthetic challenges, it was decided to approach this as a combination case, with the two centrals being produced with Captek Nano and the laterals with pressed ceramic veneers (Figure 3). The clinician was initially skeptical that a PFM could blend esthetically with all-ceramic veneers in the anterior region. After hearing that Captek can block out underlying colors, yet still provide a clean, bright, and controllable canvas for creating the natural chroma and value,10 he agreed. In the author’s experience, Captek allows the ceramist to see in the laboratory the final crown shade that will closely represent the shade in the oral environment. Thus, for the author/ceramist, the Captek substructure made the matching process and the clinical outcome more predictable.
Prior to fabrication of the veneers, care was taken to produce accurate-colored stump dies (IPS Natural Die Material, Ivoclar Vivadent) for the lateral incisors. The veneers were produced first, placed on the stump dies, then the Captek crowns were layered to match (Figure 4). The final case inserted in the mouth is shown in Figure 5. All goals in regards to eliminating the influence of the underlying tooth structure, maintenance of proper contours, blend-in at the gingival, and the esthetic match of full-contour metal-based restorations to pressed porcelain veneers were achieved.
It is important to note that the crowns did not have porcelain margins, but rather metal to the edge. Porcelain margins—while recognized as the most esthetic option on PFM or zirconia substructures in ideal situations—can be highly problematic if used on dark teeth. The darkness can be pulled right through the margin and broadcast into the body of the crown and reflect poorly in the tissue. This situation is depicted in the following case.
Case 2—Management of Translucency at the Margin
In this case, a Captek crown was prescribed for the patient’s left central due to an awareness of the issue the dark preparation created (Figure 6). A porcelain margin was planned in an effort to achieve the best possible esthetics. A very deep shoulder was prepared to provide for a thicker porcelain margin to help mask out the darkness. Figure 7 shows the insertion of that crown. Even with a large shoulder preparation, the low value from the preparation was pulled right through the ceramic porcelain margin and into the tissue, even though there was additional room for ceramics. The low value at the gum line created a completely unacceptable result. The crown was re-made, this time with thin Captek Nano metal to the margin to block out the darkness. Figure 8 shows the insertion of the second crown. In this case, eliminating the porcelain margin made a dramatic difference in the esthetic clinical outcome. Because the Captek Nano material is so thin, does not oxidize, and therefore requires very little opaque to mask, no sign of darkness or excessive opacity is visible at the margin.
These cases show how Captek Nano can provide a common-sense solution to difficult clinical situations. With high-strength factors, an ultra-thin coping, the bright gold color, elimination of oxides/corrosion, and minimization of harmful bacterial plaque, Captek Nano offers a predictable restorative option in the quest to provide long-term esthetic results.
The author would like to thank Dr. Thomas Hedstrom of Worcester, Massachusetts, and Dr. Roger Dunphy of Ft. Meyers, Florida, for their dentistry, photography, and contributions to cases one and two respectively. Thanks are also due to the Argen Corporation in San Diego, California, for assistance and contributions toward this article.
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8. Gottehrer NR. The periodontal crown: creating healthy tissue . Dent Today. 2009;28(5):121-123.
9. Lowe RA. Comparison of Captek Nano EZ vs. porcelain to zirconia all ceramic crowns in the aesthetic zone: a case report . Oral Health. 2012
10. Nathanson D, Nagai S, Po S, et al. Preliminary evaluation of the effect of crown on gingival color. Presented at the IADR Meeting March 1-13, 2004; Honolulu, Hawaii. Abstract 1478.
About the Author
Al Fillastre, BS, CDT