Tricks of the Trade

Porcelain Condensation

CONDENSATION IS AN OFTEN misunderstood term in the dental industry. For all intents and purposes, condensation is the elimination or reduction of void space between unfired porcelain particles. When porcelain is not properly condensed, gross shrinkage may occur which will result in lifting of the opaque near the margins. What's more, the porcelain can tear, especially near the interproximals and occlusals.

Study the case to the left: Hypothetical porcelain particles in the shape of flat plates are randomly distributed in diagram "A." Notice the space that exists between them--a direct result of the way the particles are randomly "stacked." During build-up, this space is filled with liquid while the porcelain is being applied to the framework. If, during the firing process, the particles are allowed to remain with this "extra" space after the fluid evaporates, then problems such as lifting, shade matching, cloudiness, and bubbling may occur.

Now look at the diagram "B." These particles are packed and aligned together tightly; no void space exists between them. The porcelain is properly "condensed" and the probability of problems occurring is greatly diminished.

What this Means for Creation Users

Creation, just like any other porcelain, needs to have the particles arranged to reduce void space. However, Creation does not require "vibration" to achieve this condensation.

"Creation can be thought of as 'self-condensing,' in that it is the movement of the Modeling Liquid through the particles that encourages them to properly align and fill space," said John Slanski, Research and Development, Jensen Dental. "But beware, condensing in this manner is not as easy to achieve as condensing through vibration."

Slanski explained that "it takes a little practice" to perform, and recommends that the best way to achieve optimal results is by watching a demonstration. "Oral Design members make it a regular practice to show this technique during their seminars," he said.

Slanski also said that it's that type of condensing that makes Creation crowns so vital. "This technique allows the porcelain to be built up in discrete layers. If you're experiencing excessive shrinkage, lifting of the porcelain, and/or tearing, follow these tips - and you'll see a difference:

1. The porcelain must be handled wet, a bit more than what you may be used to.
   

2. Liquid should be drawn through previously placed porcelain, not blotted from the surface.
   

3. Draw liquid as the build-up progresses, rather than waiting until the build-up is complete.
   

4. Use the Creation Modeling Liquid to "self-condense." DO NO USE other brands of modeling liquid.

For more information, please call Jensen at 800-243-2000.

Revision 0, 3/19/99