Zirconia, for dental crowns and bridges was first introduced by 3M as Lava. With the Lava system the white zirconia was milled and copings were dipped into one of eight different colorants to obtain a shade close to the final restoration. Today, there are still many companies providing white zirconia discs and green state coloring liquids and many labs are using a coloring system on zirconia. Many coloring systems today include 16 Vita shades, enamels, and many modifiers. With proper technique, one can obtain very natural esthetics, especially when combining the new super translucent zirconia, a matched coloring system, and a well-trained technician. Here are three paths to coloring green state zirconia.
Three Coloring Techniques
Dipping: Simply put, remove milled units from the disc, clean thoroughly and place them in a well containing the related final shade. Let the crown saturate for about 30-120 seconds (use manufacturer’s recommendations for time) remove and dry prior to sintering. This technique will result in a monochromatic restoration.
Hybrid Technique: Start with brushing an inhibitor or enamel shade to the incisal area and then dipping the crown as discussed above. The inhibitor generally has no color, but partially fills the pores of the zirconia. As a result, when dipped, the body shade penetrates less into the areas where inhibitor was painted, leaving the incisal area where the inhibitor or enamel shade was painted less chromatic. This will result in a restoration with a body and enamel shade.
Brush Technique: The application of all colorants by using a brush. This technique will result in the most esthetic results. For instance, a trained technician can paint a darker cervical shade around the margins, add a lighter body shared to the middle third and enamels to the incisal third. In addition, modifier colors can be applied for different effects. This technique does have a learning curve to obtaining consistency of the end result but offers the potential for the most esthetic result.
For best green state coloring results, it is recommended to use a manufacturer’s matched disc, liquids set, and recommended manufacturer techniques.
Thanks for reading,
Bob Cohen, CDT