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Polishing Retainers like the Pro’s |
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Originally published April 2007
Polishing Retainers like the Pro’s
The great thing about lab technicians is that they are creative by nature. Give them a challenge and they figure out how to get the job done. That means that for every basic procedure, there are numerous ways of completing the task - all potentially effective, just different. With the rising popularity of our monomer and polymer products, we have been getting more and more questions on the finishing aspect of making acrylic appliances. Everyone has figured it out, but some labs just seem to have the process down. We recently interviewed our technical advisor, John Dorsey - owner of DW Lab in Wheaton, Illinois regarding his techniques for a high luster finish on retainers.
John, what do you feel is the most important element in getting a high quality polish on your retainers?
Like any other procedure in the lab, a great polish all comes down to the right equipment and materials; a good lathe, a lab handpiece, and the right burs, buffs, and polishing compounds. Also, expecting your final polish steps to do all the work is a mistake. You need to do the job correctly right from the beginning. Scratches, lines, and ridges are extremely difficult to remove with a rag wheel and final polish compound.
How much does the initial surface finish after trimming effect the final polish?
The finish you leave after your trimming step is of ultimate importance. I’ll even backtrack a step and say that the smoothness of the palatal surface you attain after acrylic-ing is important. I’ll try to get as uniform a surface as possible before I put the retainer in the pressure pot.
Can you review the basic steps required to go from trimming to final polish?
Once the retainer is fully cured, I trim with a coarse bur in my handpiece for gross material removal. I’ll then switch to a fine bur to improve my surface finish. In the old days, I used a mandrel with sandpaper to remove the scratches left by the bur. Now, I use a mounted silicon point to give me as smooth a finish as possible before I go to the lathe. Next, a medium/fine pumice should give you a very smooth finish. I’ve been using the synthetic Pro-Polish material from Wehmer for my pumicing step. The harder I push, the coarser the material acts. With light pressure, I get a very smooth finish. After this pumice step there should be no bumps, ridges, or deep scratches in your appliance. Next, I use a low-shine polish like White Diamond as a prep for the final high gloss. Tripoli falls into this category as well, however it is a little more messy. At the end of this step, your appliance should be flawless. The final polish is exactly that. Don’t expect it to remove any additional material. As a final step, I use Wehmer’s Sure Shine product to give my retainer that deep rich shine. For the wires, I remove all wax with steam prior to any polishing and make sure the wires are dry. Use a separate rag or chamois wheel with a final polishing media like Fabulustre. Hold on tight, because polishing the wires can pull the appliance from your fingers.
Is there anything different about your method?
I’m not sure how different this is, but I make sure I use a different, dedicated wheel for each step. I also use a separate set of wheels for wires that I don’t use for acrylic. Back in the day, I used my polishing wheels to knock off wax, but I found that the wax would load the wheels and make them ineffective way too fast. Now I simply remove all wax with steam before I begin any polishing.
Is there a difference in acrylic materials when it comes to a high luster appliance?
You can sometimes notice a difference in acrylic brands when it comes to initial trimming with a bur. Some materials just feel softer, and you can really tell the difference when you are trimming a glassy acrylic. When it comes to polishing, I really haven’t noticed much of a variance in how these materials respond to polishing compounds.
Where can the process go wrong for beginners?
In my experience, starting out with a really lumpy appliance can be a problem, because you end up trimming more with a bur than you bargained for. Leaving deep scratches and ridges after trimming and expecting the pumice to remove gross material can be a big mistake. Also, I have seen in-office labs that only use a single polishing compound and expect it to do the entire job. A great polish is an incremental operation. What you do at the very beginning can have a big impact on your end result.John Dorsey / DW Lab
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2009 Laboratory Equipment and Products (3962)