Polishing Zirconia

There has been a major paradigm shift in the indirect restorative choices that are being prescribed in the majority of dental practices. These changes have produced very appealing results, but they are also creating new challenges. One of the most common questions that all of us in dental labs in California hear quite often is this:

“What is the best way to adjust and polish zirconia restorations?”

Adjusting

There are many great products that will facilitate the results that are required when adjusting and then polishing zirconia restorations. First, evaluate if the adjustment needs a diamond. If there is minimal adjustment, use an abrasive polishing wheel or point, which will save time. A diamond is needed only if there is a significant adjustment to be made.

If you determine that you need a diamond to accomplish the amount of adjustment, there are some rules to follow:

1. Use a friction grip slow speed handpiece.

2. Use a fine grit diamond. 

3. Run at 20,000 RPM with ample water.

4. Keep your touch light to avoid excess heat.

Brasseler, Comet, Axis, and most abrasive companies have diamonds recommended for zirconia adjusting. (Brasseler: 8639DF-025)

Polishing

It is universally agreed that it is important to achieve a highly polished surface in any ceramic restoration, but it is essential for zirconia restorations. While most of the porcelain polishing rotary instruments will deliver an acceptable polish, I have observed that the abrasives that are designed specifically for zirconia deliver a better polish with less effort. As with the diamonds, the most abrasive companies have a specialized product line for zirconia. Typically this is a 2 step process.

1. Begin with the medium/smoothing abrasive. Beginning with a slower speed (5,000 RPM) use medium pressure, but then move to higher speed but with a very light touch.(Brasseler W17MZR-Medium)

 

2. Finish off with a fine polishing abrasive to achieve a highly polished surface. This is typically done at higher speed (15,000) and with a light touch, just to buff it out to a high shine.  (Brasseler  W17MZR-Fine)

 

These steps will deliver a very effective polish intra-orally in minimal time.  (Fig. 4)