Achieving Superior Esthetics with Pre-Shaded ArgenZ Anterior Super Translucent Zirconia
Inside Dental Technology delivers updates on digital workflows, materials, lab techniques, and innovation in dental technology through expert articles and videos.
May 1, 2016
Volume 7, Issue 5, May 2016
Page(s):
By Chris Lowthorp, CDT
Pre-shaded zirconia has become popular with dental laboratories due to the time-savings and shade consistency the base shade provides. With pre-shaded zirconia there is no need for laboratory technicians to shade each unit in the green stage, saving production time and freeing them up to produce more units. However, standard pre-shaded zirconia systems require the dental laboratory to stock an inventory of 16 shades, each in a large selection of disc thicknesses to cover all unit shades and sizes. Furthermore, you can mill only one shade at a time, thus tying up your mill.
The ArgenZ Anterior Value Shaded Disc System is a collection of pre-shaded super translucent zirconia that covers all 16 shades of the VITA Classic shade guide with just six value-shaded discs. Each disc covers 2-3 shades based on value and chroma, requiring much less inventory and mill time. No green stage shading is required. You simply design, mill, sinter, and stain and glaze.
The discs are as follows:
• Disc 1: Shades A1, B1
• Disc 2: Shades A2, B2, A3
• Disc 3: Shades C1, D2
• Disc 4: Shades C2, D3, D4
• Disc 5: Shades A3.5, B3, B4
• Disc 6: Shades A4, C3, C4
Similar to the 16-disc shade systems, each ArgenZ Anterior Value Shade Disc group will be approximately one-half shade lighter than the lightest shade in that group. This makes it easy for the technician to change hue, adjust chroma intensity, and create a good incisal transition zone with external chroma stains.
Traditional all ceramic systems are low in value, especially the light high value shades such as A1. The ArgenZ Anterior Value Shaded System is formulated to deliver a true value to match the guide.
The translucency of ArgenZ Anterior and the additional light refraction from the cubic ZR phase results in a natural incisal translucency requiring little to no incisal staining. Units with thicker incisals may require some minor incisal enhancement with incisal enhancement stains.
Many companies make a low fusing fluorescent stain-and-glaze system designed primarily for all-ceramic systems. The most important stains in the kits are the A, B, C, and D chroma stains. These stains are essential to stain up to the next chroma or shade level in each shade group. Incisal stains or intensive blue stains can be customized with black, white, or violet to make any incisal enhancement color needed.
Stains do not penetrate zirconia, so it is not necessary to fire above 800°C. The systems the author uses allow stains to be fired at 750°C (fully melting) and glazes to be fired at 730°C.
Units must be seated on a die for final staining to match the shade guide. Due to the translucency of anterior zirconia, the final shade is slightly affected by light diffusion and the color of the underlying die and preparation. The anterior unit will appear to have a higher value and slightly more chroma when seated on a die.
Using a die color coating system to match preparation shades (stump shades) is recommended. Preparation coloring systems contain a variety of colors to match light to dark shades (Figure 1 through Figure 3). If you do not have guidance on preparation colors (picture or preparation shade), match the die shade color to the prescribed base shade.
The following steps should be taken before staining and glazing:
1. Make any anatomical adjustments or additional surface texture. Use grinding and polishing tools designed for zirconia to avoid overheating.
2. Smooth and polish any areas that will be in occlusion.
3. Lightly air abrade to remove surface tension with 50-micron aluminum oxide at 20-30 psi (1.5-2 bar). Ultrasonic clean in distilled water.
1. Seat the unit on a shaded die and apply a light coat of stain liquid (Figure 4).
2. Apply “A” chroma stain to the body and blend to the incisal to match the A1 shade guide for all surfaces (Figure 5).
3. Apply an incisal enhancer stain if needed and fire in a porcelain furnace. Figure 6 shows no incisal stain is needed on this unit.
4. Check the shade. Apply a thin layer of stain liquid. Apply more stain if needed and fire in a furnace (Figure 7).
5. Completely cover the unit with a thin layer of glaze (Figure 8) and fire in a porcelain furnace.
6. Conduct a final shade check (Figure 9).
Figure 10 shows the final 3-unit anterior bridge restoration. Posterior units are stained using the same technique with the exception of additional occlusal staining if prescribed (Figure 11).
Chris Lowthorp, CDT, is the Owner of Digital Dental Aesthetics, LLC, R&D/Consulting/Education.
The statements and opinions contained in the preceding material are not of the editors, publisher, or the Editorial Board of Inside Dental Technology.
Manufacturer Contact Information
Argen
argen.com
800-255-5524
