Boxing final imp for master cast?

[eleminopee]

My wonderfully expensive and frustrating school is teaching us to "bead and box" a final impression in order to then make a master cast of an edentulous maxillary and mandibular ridge with acceptable land areas.

The process: melt sticky wax along the outside border of the final impression. THen melt rope wax to the sticky wax and flatten the rope wax in order to make what will become in the master cast the land area. Then encircle the whole thing with boxing wax and melt the waxes together so no microstone leaks through when you pour it up. Once your cast is poured you have to go through and clean it up a ton

i KNOW there has to be a better, faster method than this. The waxes don't stick well to the PVS material used for the final impression, and the whole process takes FOREVER.

Any other methods out there?

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[OceanDMD]

use an ortho base mold. Little more grinding, less time and no wax.

 

[eleminopee]

use an ortho base mold. Little more grinding, less time and no wax.

can you elaborate please? I don't know what an ortho base mold is or how to use it

 

[KOM]

My wonderfully expensive and frustrating school is teaching us to "bead and box" a final impression in order to then make a master cast of an edentulous maxillary and mandibular ridge with acceptable land areas.

You're not the only one. Not to mention if the cast gets an air bubble, you may have to re-seat and seal the damn thing all over again.

So good question.

 

[OceanDMD]

can you elaborate please? I don't know what an ortho base mold is or how to use it

They make plastic molds of impression bases for ortho or diagnostic casts. Essentially you pour up your impression, fill the mold, and invert the impression on the mold. With a denture patient, pour the impression, let it set, remove from impression. Fill the mold, place the model tissue up into the wet stone, and sink it just to the border. Then you can take a spatula and rough out a landing area.

 

[charlestweed]

Mix the alginate and pour it into another green alginate bowl (make it more than half full). When the alginate is still soft, push the final denture impression tray into the alginate until its border is 3-4mm above the level of the alginate. You are now ready to pour the impression for your master cast. Your final impression tray is basically embedded in the sea of alginate (instead of the rope wax) and the upper part of the alginate bowl will hold the microstone like the boxing wax.

I think OceanDMD's technique is simpler and faster.

 

[Str8Tth]

!

 

[PrePerio]

I just tried a new technique and am in love 😍

Mix 50% plaster, 50% pumice in a rubber mixing bowl. Pretty much fill the whole bowl up with the two powders and add water until it's coated but super-duper thick.

Take a piece of aluminum foil, paper towel, etc and dump most of the pumice/power mix onto it. Confirm that it is firm but not fully set. Take the master impression and shove it into the plaster/pumice until it gets close to the border molded area. Use the mixture left in the bowl to build up the rest to the desired location of the land area.

Take some vaseline and put a thin amount on the top of the plaster/pumice then pour.

This method is pretty similar to the alginate method, but the working time of the plaster and pumice is a little longer, and it's easier to add if necessary.

If anyone has any tips on how to avoid beading and boxing an altered cast impression, I'd LOVE to hear it!

 

[ivorinedust]

I heard some labs use flexible magnet tape around 2 " to 3" wide and wrap it around the impression like boxing wax. The magnetic tape would of course retain as it wraps around itself, and would adapt to the impression because it is flexible. They'd probably melt some wax between the impression and the inside of the magnetic tape to seal in the stone mix. I haven't tried it, but it seems simple enough to do, aside from being reusable.

Ivorinedust

"Apolonia relieved my toothache!"

 

[aphistis]

Playdoh, and lots of it (you can find a recipe online to make your own cheap out of flour and water). Take a big ball of the playdoh, press the denture impression into it, mold the playdoh to create your land area, then take your boxing wax and form it around the playdoh "bead". Go around the wax with a hot spatula to seal the edge. Wait about 15 minutes for the playdoh to dry out some, then pour the stone into the mold/impression. Some profs don't like using the rubber base formers because that inverts an impression and causes the air bubbles to rise to the tissue surface, leaving voids on the ridge. This way, air bubbles rise to the top of the pour, which you will grind off anyhow.
Hope this helps

I always used the play-dough method. Worked pretty well for me.

 

[Lidopaine82]

Mix the alginate and pour it into another green alginate bowl (make it more than half full). When the alginate is still soft, push the final denture impression tray into the alginate until its border is 3-4mm above the level of the alginate. You are now ready to pour the impression for your master cast. Your final impression tray is basically embedded in the sea of alginate (instead of the rope wax) and the upper part of the alginate bowl will hold the microstone like the boxing wax.

I think OceanDMD’s technique is simpler and faster.

Does this work for the mandibular cast as well?

 

[charlestweed]

Does this work for the mandibular cast as well?

Yes. Don't worry when you see the alginate flows into the retromolar pad area. Ater the anginate sets, you can take the whole alginate/denture tray complex out of the green bowl and trim the alginate to a desire level with the lab knife and wax spatula.

 

[armorshell]

During the first week of class, they told us never to box our impressions of dentulous patients because it would distort the teeth. I recently had the chance to box and pour a removable impression for the first time, and now I wonder why they didn't just tell us not to do it because it wastes 90 minutes of your life.

 

[Hemogoblin]

I might have been taught differently, but what exactly are we talking about here? Duplicating master casts for F/F? Or the actual pouring up of secondary impressions? Can someone please clarify as I find this discussion very interesting 🙂

Cheers

 

[eleminopee]

I might have been taught differently, but what exactly are we talking about here? Duplicating master casts for F/F? Or the actual pouring up of secondary impressions? Can someone please clarify as I find this discussion very interesting 🙂

Cheers

we're talking about taking a final impression of an edentulous mouth and finding the best method to pour that impression up into a master cast for working with 🙂

 

[Hemogoblin]

Thanks 🙂 But isn't it just a matter of pouring it up as one would "normally?" I take it these impressions are taken with special trays, using something like an initial wash followed by a secondary, heavier body impression material? If they are, I don't see the need for any special boxing, pouring, etc? The landmarks should be well taken, as should all the extensions. I asked the question because we were never taught to use that method.

Cheers

 

[haisha ni narou]

When I worked in a lab, we would pour the model and while the stone was starting to set enough to stack, we would stack 3 lumps a few cm's in length. Once the cast was hard, we would mix up another batch of stone and fill the land area between the lumps with stone (to avoid air pockets) then make a big fat hocky puck (with the leftover stone) on a plate then invert the cast tissue-up and plop it down on the hocky puck using a spatula to lift the stone up in the voids. this is the way some Prosthodontists showed me, fairly simple not so technique sensitive and the "lumps" work as rebar to reinforce the two separate stone batches. Essentially the same thing Ocean said without the plastic form.

Hope that made sense.

 

[1992Corolla]

It is your final impression. You have to pour it up in stone so it includes all the edges of the impression (the part that got the sulcus/[sulci?]). In order to pour up the stone model to include the edges there are various methods.

I didn't like the 50:50 plaster😛umice mix method, I just always beaded and boxed, which if you are good can take all of 15 minutes.

Place sticky wax about 3mm below the edges (the sulcus part of the impression) all the way around. If you do this with a waxing instrument it will take 90 minutes. Just pick up the stick of wax, flame it and wipe it around the impression.
Then wrap rope wax around so there is a substantial ledge. Then wrap some boxing wax around the whol impression. Turn it upside down and with your wax spatual flamed quickly seal everything.

15 mintutes. Let it cool to room temp before pouring and use room temp water so the wax doesn't distort anything while pouring it up.

We would do this in a lab with 125 bunsen burners running mid summer. That causes distortion.

Here is my final denture:
http://www.dmdstudent.com/2008/05/27/completing-the-dentures-and-pictures/#more-150

 

[OceanDMD]

it is your final impression. You have to pour it up in stone so it includes all the edges of the impression (the part that got the sulcus/[sulci?]). In order to pour up the stone model to include the edges there are various methods.

I didn't like the 50:50 plaster😛umice mix method, i just always beaded and boxed, which if you are good can take all of 15 minutes.

Place sticky wax about 3mm below the edges (the sulcus part of the impression) all the way around. If you do this with a waxing instrument it will take 90 minutes. Just pick up the stick of wax, flame it and wipe it around the impression.
Then wrap rope wax around so there is a substantial ledge. Then wrap some boxing wax around the whol impression. Turn it upside down and with your wax spatual flamed quickly seal everything.

15 mintutes. Let it cool to room temp before pouring and use room temp water so the wax doesn't distort anything while pouring it up.

We would do this in a lab with 125 bunsen burners running mid summer. That causes distortion.

Here is my final denture:
http://www.dmdstudent.com/2008/05/27/completing-the-dentures-and-pictures/#more-150

i

 

[dentwannabe]

We do the same method as your school MINUS the sticky wax. We simply line the impression with a strip of rope wax. And then box this. If you see any openings, fill it in with melted red wax. Make sure the impression is perpendicular to the boxed wax and you should be good. Didn't take too long at all.

Now trying to get the right freaking final impression - THAT TOOK LONG!!

 

[I'mFillingFine]

Thanks 🙂 But isn't it just a matter of pouring it up as one would "normally?" I take it these impressions are taken with special trays, using something like an initial wash followed by a secondary, heavier body impression material? If they are, I don't see the need for any special boxing, pouring, etc? The landmarks should be well taken, as should all the extensions. I asked the question because we were never taught to use that method.

Cheers

The main reason to bead and box is not to make sure you get all the anatomy in the pour. It's to avoid "inverting" the pour (most people do this once they fill the impression; turn it over onto a pile of stone.) Since some of the stone settles immediately in the fluid pour, the densest area is always on the bottom. If you're able to make a "cup" over the impression, the densest stone is at the teeth and/or edentulous ridges. Right where you want it!

It's also a good technique to avoid breaking off teeth when you take the impression off (since they'll be stronger._

 

[armorshell]

The main reason to bead and box is not to make sure you get all the anatomy in the pour. It's to avoid "inverting" the pour (most people do this once they fill the impression; turn it over onto a pile of stone.) Since some of the stone settles immediately in the fluid pour, the densest area is always on the bottom. If you're able to make a "cup" over the impression, the densest stone is at the teeth and/or edentulous ridges. Right where you want it!

It's also a good technique to avoid breaking off teeth when you take the impression off (since they'll be stronger._

You could also do a two step our, where you make some positive architecture "pillars" on the top of the first pour, wait for the stone to set completely, then invert it onto a patty of stone to form the base which interlocks in with the pillars you made on the first pour.

The only downside I've noted is the color of the model and base are slightly different.

 

[haisha ni narou]

You could also do a two step our, where you make some positive architecture "pillars" on the top of the first pour, wait for the stone to set completely, then invert it onto a patty of stone to form the base which interlocks in with the pillars you made on the first pour.

The only downside I've noted is the color of the model and base are slightly different.

Wow, you explained this so much better than I did.

 

[I'mFillingFine]

You could also do a two step our, where you make some positive architecture "pillars" on the top of the first pour, wait for the stone to set completely, then invert it onto a patty of stone to form the base which interlocks in with the pillars you made on the first pour.

The only downside I've noted is the color of the model and base are slightly different.

This is a good idea too, though I've had the base separate on me before (even after doing lots of surface area and soaking the stone first.) Sometimes I just make a thicker stone and pile it up on top of the impression. 😀 Sort of like beading and boxing without the beading and boxing! (Then I usually prop it up with some paper towels or a blob of wax.) Yay lazy!

 

[benitz2]

I just tried a new technique and am in love 😍

Mix 50% plaster, 50% pumice in a rubber mixing bowl. Pretty much fill the whole bowl up with the two powders and add water until it's coated but super-duper thick.

Take a piece of aluminum foil, paper towel, etc and dump most of the pumice/power mix onto it. Confirm that it is firm but not fully set. Take the master impression and shove it into the plaster/pumice until it gets close to the border molded area. Use the mixture left in the bowl to build up the rest to the desired location of the land area.

Take some vaseline and put a thin amount on the top of the plaster/pumice then pour.

This method is pretty similar to the alginate method, but the working time of the plaster and pumice is a little longer, and it's easier to add if necessary.

If anyone has any tips on how to avoid beading and boxing an altered cast impression, I'd LOVE to hear it!

This is a great method, fast and reliable.....the only difference is that we use Super Sep solution instead of Vaseline, it is fail proof

 

[Dr. Dai Phan]

Hi all,

As a former assistant professor of prosthodontics, let me chime in here. I can say that in the dental schools that I was in (4), students were taught to do certain procedures without recieving adequate explainations on the rationales. They all did what were told but never understood on why. In order to do certain procedures correctly, you need to know what you are trying to achieve. Now, let's look at the bead and boxing final denture impressions. Do you HAVE to bead and box? The answer is NO. Just pour up the impressions as you would with any impressions and then you can trim the land area down after the casts are seperated. The time it takes to fumble with the wax will be way more hassle and takes way more time to trim the casts. You probably have learned that boxing and beading wax are not "too friendly" with impression materials by now. They are not "coffee and donuts " I can tell you. Then you may ask "then why am I taught this way?". You are taught this way because that is the way it is written in text books but this is the real reason. This is to ensure that you capture the borders of the impressions in stone so the dentures can have their proper border extensions (or all the bordermolding process is wasted! ). You can skip the beading and boxing process if:

1. Your professor allows it (if the moon turns blue).
2. Sink your impressions in stone enough to capture the border areas.

I used to bead and box as a newbie but once I know what the procedure is trying to achieve, it became history. Boy do I miss my teaching days... DP

 

[1992Corolla]

obviously in private practice all you ever need is an alginate impression and a stone model and let the dental tech design the denture...

I think most of us understand why we need to bead and box, I just thought we were talking about easier methods.

 

[Dr. Dai Phan]

I think most of us understand why we need to bead and box, I just thought we were talking about easier methods.

That's why I suggest doing step 2 as recommended. DP

 

[TTHRGr8T]

If you are trying to "bead and box" a pvs final denture impression [or any pvs impression for that matter], use polyvinylsiloxane impression material tray adhesive instead of the sticky wax. Apply it with a disposable Bendabrush the width of the beading [square rope] wax all along the final impression. This works better than the sticky wax. Also, another tip is to slightly warm the beading wax over your Bunsen burner so it is more pliable.

The pumice/plaster method works well for the mandibular arch...beading and boxing makes a little "prettier" cast so I always bead/box the maxillary impression as it is just as quick. When you get a little more experience the beading/boxing doesn't take so long....maybe 15 minutes for the lower and 7-10 for the upper. Getting the wax to stay on the impression will help speed things along. Good luck!