polishing PMMA

[RileyS]

I have a 9 unit temp milled out of PMMA that I need to plush. Tried some compounds with a white felt(?) Wheel I use for ceramics. Didn't do so great. Also tried the Robinson (horse hair) wheel that was worse. Any tips?

 

[j.abadsantos]

I use a lot of primoglaze from primotecusa.com

 

[RileyS]

Is that a coat of liquid stuff and light cured?

 

[j.abadsantos]

yes

Is that a coat of liquid stuff and light cured?

 

[RileyS]

I found some palaseal here, same idea as primo tec stuff?

 

[j.abadsantos]

have you tried pumice?

 

[j.abadsantos]

i haven't tried palaseal yet, as long it makes it shiny why not

 

[Marcusthegladiator CDT]

Careful with the paliseal... It cures with a dark tint to it. I was building my temps much lighter to compensate.
If you build a lot of temps you can go with an expensive bottle of paliseal. But the "Radica," sealer is the same thing, only no tint. Much easier to apply.
And at only $14.00 a bottle its a steal! And polishes to a fingerprint proof sheen much easier than paliseal.
When I found out it was only $14.00 I ordered 5 bottles and started putting it on my toast.
We build a lot of temps. The trick is to seal the temp and before the cure, blow all the excess off with the compressed air. Then cure for a minute. Now apply another coat the same way, blow it all off and you have a beautiful texture that's bubble free. and cure....
I put some crap in my light curers button so I can cure with the door open. I just hold it on my tweezers and spin it around for a minute, by then its cured enough to touch and lay down. So you don't have to bother trying to settle the wet bridge on some pegs and get your finger prints all over it...

Call DENTSPLY and ask for the $14.00 bottle of, "Radica Provisional Sealer."

 

[RileyS]

Thanks gents. I'll do a test spot on lingual with palaseal. I'll get some radica too

 

[JohnWilson]

I onloy use light cure glaze to modify shades on temps. My goal is to have nothing on the PMMA and have it be super high shined.

I use a fine cross cut bur made for composite finishing to shape and finalize contour

I use standard synthetic pumice with a B20 brush light pressure, with a very quick shine with a 3" buff with red moltloid compound.

I finish the case with a star shape goat hair white brush and then a final high-shine with Bredents polish.

10 min's tops and it shines like a mirror with no flaking or discoloration that can happen with light cure gloss.

 

[kcdt]

I onloy use light cure glaze to modify shades on temps. My goal is to have nothing on the PMMA and have it be super high shined.

I use a fine cross cut bur made for composite finishing to shape and finalize contour

I use standard synthetic pumice with a B20 brush light pressure, with a very quick shine with a 3" buff with red moltloid compound.

I finish the case with a star shape goat hair white brush and then a final high-shine with Bredents polish.

10 min's tops and it shines like a mirror with no flaking or discoloration that can happen with light cure gloss.

One is always better off polishing PMMA. The LC varnishes invariably look like crap in a very short time and seem to be plaque magnets.

 

[Sevan P]

Pearson Lab Varnish here and light cure, or you can take pumas and polish it up on a lathe. So far with the PMMA from TD the lab varnish works great, looks sooo pretty. Just got some more PMMA in today from TD $40.00 for any size up until 20 or 25mm then it is $45.00 cuts and looks great.

 

[AJEL]

I put some crap in my light curers button so I can cure with the door open. I just hold it on my tweezers and spin it around for a minute

Marcus, the cure light has a strong UV content 400- to 515-nanometer wavelength bandwidth, wear some sort of yellow laser UV eye protection or figure on early Macular Degeneration as the UV thins your retina.

http://macuhealth.com/wp-content/uploads/2012/12/Assessment_of_the_Validity_of_in_vivo_Methods_of_Measuring_Human_Macular_Pigment_Optical_density.pdf

UV curing lights & eye protection


Ultraviolet phototoxicity to the retina. [Eye Contact Lens. 2011] - PubMed - NCBI

 

[Marcusthegladiator CDT]

Marcus, the cure light has a strong UV content 400- to 515-nanometer wavelength bandwidth, wear some sort of yellow laser UV eye protection or figure on early Macular Degeneration as the UV thins your retina.

http://macuhealth.com/wp-content/uploads/2012/12/Assessment_of_the_Validity_of_in_vivo_Methods_of_Measuring_Human_Macular_Pigment_Optical_density.pdf

UV curing lights & eye protection


Ultraviolet phototoxicity to the retina. [Eye Contact Lens. 2011] - PubMed - NCBI

Thanks, I usually stare away from it. It's as bright as the sun when your on top of it.

 

[PCDL]

Mechanical polishing is pretty easy with PMMA, you just need to SLOW DOWN. I use polishing points designed for Acrylic work (Komet) and I keep the rpms down to 10k or less. Start with the rough, go to the medium, and then finish with a high shine from a Robinson brush (soft, the dark hair) and some C&B polishing paste. you want to use the acrylic points in a horizontal pattern, and the Robinson in a vertical pattern. Leaves a perfect finish. The Robinson should spin at 5-7k rpms. I dont bother with the glaze liquids.

 

[PCDL]

Here are a few pics... this took me 10 mins tops...

 

[RileyS]

Here are a few pics... this took me 10 mins tops...
View attachment 5695 View attachment 5697 View attachment 5698 View attachment 5699 View attachment 5700 View attachment 5701 View attachment 5702 View attachment 5703

Hi PCDL, I somehow totally missed this post till today!! Awesome!! Thank you so so so much!

 

[doug]

I'm glad I read this thread. I got a PMMA temp bridge in last Friday and it was due this morning...Surprise, that wasn't the finish date. I used the same process to polish it as I do bite splints. A little work with a carbide to smooth the milling lines and pumice. Dam, it looked good for not doing anything else to it. I WAS gonna put a little flair into it with my light cured stains. Maybe next time.

 

[eyeloveteeth]

i've been telling the techs to just use a bristle wheel and maybe some diamond paste, but it shines up real fast

 

[dmonwaxa]

PMMA,,,, Polymethyl Methacrylate, acrylic resin; same as most other denture base materials,,,,,so whatever is used to polish dentures, the same can be used for PMMA. Old school Jet Acrylic polished up nicely with just pumice and a touch of white buffing compound, same with PMMA. PMMA just like "Jet" (Glorified Jet) only the delivery system is different.

edit: And Oh yeah,,,smaller polishing rotaries required!