question about making provisionals/temps for crown preps

[accu94672]

I have a question for those who know how to make provisionals/temporaries for crown preparations.

After I remove the provisional from my matrix ( usually polyvinyl silo ), I end up getting a provisional that's a lot higher than what its respective tooth is supposed to be. But when I trim the provisional's occlusional surface to its correct height, I lose most of the occlusal anatomy.

The occlusal surface of the provisional becomes more flat and its cusps are no longer as noticeable. Is this what a provisional is supposed to look like in the end? If not, can anyone provide me with some feedback?

Thx.

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[Dr.SpongeBobDDS]

I have a question for those who know how to make provisionals/temporaries for crown preparations.

After I remove the provisional from my matrix ( usually polyvinyl silo ), I end up getting a provisional that's a lot higher than what its respective tooth is supposed to be. But when I trim the provisional's occlusional surface to its correct height, I lose most of the occlusal anatomy.

The occlusal surface of the provisional becomes more flat and its cusps are no longer as noticeable. Is this what a provisional is supposed to look like in the end? If not, can anyone provide me with some feedback?

Thx.

Sounds like you're not seating the matrix fully when forming the provisional on the prep. Push harder or have the patient close down on a cotton roll the same way you seat a crown. 😀 Hope that helps.

 

[accu94672]

Sounds like you're not seating the matrix fully when forming the provisional on the prep. Push harder or have the patient close down on a cotton roll the same way you seat a crown. 😀 Hope that helps.

My acrylic is usually thick and doughly when I put it into the matrix. No matter how firmly I press, the acrylic wouldn't allow the matrix to seat fully.

So what should I do? The only way I can think of in seating the matrix fully is to use acrylic that is in more of a liquid-form, which I can't do because it'll spill out of the matrix and my provisionals manual says to use doughy acrylic only.

Any reply would be appreciated.

 

[aphistis]

If it's any consolation, I usually end up with the same problem on my provisionals. We use Snap, and I usually use a PVS matrix too. Bottom line, it's just a provisional; civilization won't collapse if it's missing tertiary anatomy. Maybe they exist, but I haven't met anyone in my class who doesn't have the same problem.

 

[lnn2]

My acrylic is usually thick and doughly when I put it into the matrix. No matter how firmly I press, the acrylic wouldn't allow the matrix to seat fully.

So what should I do? The only way I can think of in seating the matrix fully is to use acrylic that is in more of a liquid-form, which I can't do because it'll spill out of the matrix and my provisionals manual says to use doughy acrylic only.

Any reply would be appreciated.

Are u talking about preclinical temp?
Here're a few tips:
1. Make sure there're no undercuts in your prep. If your temp is locked on the tooth then you most likely have undercuts.
2. Use Reprosil (instead that thin piece of plastic) to make a Stint. It'll give you a very sharp occlusal anatomy.
3. Make the Stint just long enough for the temp. For ex., if u r temporizing crown #19 then make the Stint for #18 to #20 and cut the distal halves of #18 and #20 so that acrylic can escape out, and not locking onto the interproximal spaces of #20and#21 and #18and#17
4. Vaseline those teeth.
5. Mix the acrylic b/w honey consistency and doughy state. Too doughy mix will yield high occlusion and not very define anatomy. Try to fill acrylic into #19 only. Use a spatula to keep the jet acrylic filled w/in tooth #19.
If it's too runny, wait a few seconds until it sets (but before it gets to doughy state) before u put the Stint onto those teeth.
6. Use your index finger to press and hold down onto the WHOLE stint. At the same time, use the thumb and index fingers of the other hand to gently compress the lingual and buccal sides of the stint.
7. If u r using the Reprosil stint then let it sit until u can feel the heat through the stint. Then lift off the stint by pulling it from the lingual and buccal sides at the same time. Clean out the excess acrylic while it's still soft with a knife or a hatchet, especially from the interproximals. If the acrylic is still very soft then carefully put the stint back on and keep pressing down on it.

8. If u r using a Plastic stint: when the acrylic spills out of the stint, don't wipe it off. Wait a few seconds for it to set but still soft enough so u can wrap the spill out acrylic right onto the stint, lingually, buccally and occlusally. When it's harden, it'll be easier for u to lift off the provisional. It works well in clinic.
When u can feel the heat, use the explorer tip to lift the stint on and off (but not all the way off), preventing the locking on problem.

hope it helps!

 

[Dr.SpongeBobDDS]

My acrylic is usually thick and doughly when I put it into the matrix. No matter how firmly I press, the acrylic wouldn't allow the matrix to seat fully.

So what should I do? The only way I can think of in seating the matrix fully is to use acrylic that is in more of a liquid-form, which I can't do because it'll spill out of the matrix and my provisionals manual says to use doughy acrylic only.

Any reply would be appreciated.

There are still options.

1. Screw the manual. How much difference does it make if you seat the acrylic while it is still a little runny? It sets up inside the mouth pretty much like it does outside the mouth as long as you don't seat too early. Seating it 30 seconds before it reaches dough stage is not going to affect the qualities of the material to any noticeable degree. Or ask your instructor, maybe you are just overestimating what constitutes "doughy".

2. You can cut a small hole (about the size of a #4 or #6 round bur) in the occlusal surface of your matrix before you fill it with acrylic. This will let the excess escape that tends to prevent you from seating properly. This way, you just have to cut off the little button on the provisional rather than grinding down the whole occlusal surface.

Just trying to help. I know I would be frustrated too if I was needing to grind that much on my provisionals.

 

[DrJeff]

There are still options.

1. Screw the manual. How much difference does it make if you seat the acrylic while it is still a little runny? It sets up inside the mouth pretty much like it does outside the mouth as long as you don't seat too early. Seating it 30 seconds before it reaches dough stage is not going to affect the qualities of the material to any noticeable degree. Or ask your instructor, maybe you are just overestimating what constitutes "doughy".

2. You can cut a small hole (about the size of a #4 or #6 round bur) in the occlusal surface of your matrix before you fill it with acrylic. This will let the excess escape that tends to prevent you from seating properly. This way, you just have to cut off the little button on the provisional rather than grinding down the whole occlusal surface.

Just trying to help. I know I would be frustrated too if I was needing to grind that much on my provisionals.

If you're being FORCED to use SNAP by you're instructors (I'll almost guarentee you that they don't use that on their patients), definately load your matrix in a soft doughy stage, also you don't have to fill the matrix to the cervical margins (afterall you have the volume of your prepared tooth taking up roughly 2/3rd's the volume of that tooth space in the matrix), and definatelt cut a "vent hole" in your matrix to allow for the excess mass of that doughy SNAP to escape.

The reason why I say that most of your instructors likely don't use SNAP on their own patients is that with today's autopolymerizing Bis-GMA resin temorary materials (i.e. Integrity, Luxa Temp, etc) you get a more workable state initially with alot easier flow of the excess out of your matrix which translates into a more accurate temporary with less triming, and it sets in under 2 minutes from dispensing, its much more acurate(less than 1% distortion), and gives off less than 3 degrees Celsiuis of heat on polymerizing (read as less chance of frying the pulp). I have my assistants making 90% of my temps for me , and with the temp material I use (Intergrity by Dentsply), and they have it made, and the margins trimmed in less than 4 minutes

The only negative to this type of temporary material is its cost, its roughly $100 for a cartridge of material that will give you about 25 units of temporaries, or roughly $4 a unit. Considering though that with that $100 cartridge of temporary material that I'll bill out about $20,000 in fees, all the while getting a more accurate temporary and saving about 10 minutes of chairtime, its a good trade off 😀

The only positive I can see for SNAP in this day and age of dental materials is its cheap! An entire bottle of powder and liquid is about $10 and you'll get about 50 units out of that (if your paying attention with how much material you're mixing up 😉 ) But with all the heat SNAP gives off, the fact you have to "pump" the matrix during setting, the time from start of mix until full polymerization and the distortion that often occurs, the last time you'll likely use SNAP is your last temporary before you graduate 😀

 

[accu94672]

7. If u r using the Reprosil stint then let it sit until u can feel the heat through the stint. Then lift off the stint by pulling it from the lingual and buccal sides at the same time. Clean out the excess acrylic while it's still soft with a knife or a hatchet, especially from the interproximals. If the acrylic is still very soft then carefully put the stint back on and keep pressing down on it.

I really appreciate all the helpful replies on this thread. I tried out everything but unfortunately came to realize that I'm in a deeper trouble:

What should I do if my provisional ends up being stuck between adjacent teeth? ( I the blunt end of my wax spatula to take it out at this point with 50% chance of success ) I know the solution to this would have been to remove and put back the provisional repeatedly before it gets too hard but it never works for me because I'm not too sure of the timing and sometimes my margins end up tearing if I take it out in its soft state. ( and I don't feel any heat from my matrix )

This sounds weird but it started happening since I've used my new Duralay set, which is the same as the one I used previously. ( maybe it's my technique, but I don't know ) The pontic of my provisional ends up stick hard to the gingiva of my typodont, requiring extreme force that ends up gingival damage. Does anyone know why this is happening?

What do you think I should do? My practical is early next week and I'll be sent to summer school if I can't pass this course. Please help me.

 

[ItsGavinC]

I have my assistants making 90% of my temps for me , and with the temp material I use (Intergrity by Dentsply), and they have it made, and the margins trimmed in less than 4 minutes

4 or 5 months ago I posted my complaints here on the provisional material that my instructors were making us use (Trim). That stuff was nasty and HORRIBLE to work with. I was literally taking 2-3 hours to trim my margins how I wanted them.

Since then, I've switched to Integrity (which was what everybody recommended at the time, and what you've just recommmmended) and I'm done trimming in 5-10 minutes TOPS.

GREAT stuff if you can get your hands on it.

 

[DrJeff]

4 or 5 months ago I posted my complaints here on the provisional material that my instructors were making us use (Trim). That stuff was nasty and HORRIBLE to work with. I was literally taking 2-3 hours to trim my margins how I wanted them.

Since then, I've switched to Integrity (which was what everybody recommended at the time, and what you've just recommmmended) and I'm done trimming in 5-10 minutes TOPS.

GREAT stuff if you can get your hands on it.

IMHO it's the best on the market of the autopolymerizing temporary materials. My partner and I a couple of times a year will get a sample tube of a different companies material, and after making a temp crown or two with it, its back to the Integrity. The only brand we've *almost* considered switching to was luxa-temp. For us it had about 98% of the handling/trimming characteristics as Integrity, the colors of the light shades (A1,B1, Bleach shades) were slightly more natural, but it was about an extra $10 a cartridge (about $110 a cartridge).

By comparison, you can get a tube of parkell's material (Temp Span if memory serves me correctly) for about $50 a cartridge, however in my hands that tended to be very doughy with an inconsistent set time, and an extensive "slime" layer on the surface.

 

[lnn2]

I really appreciate all the helpful replies on this thread. I tried out everything but unfortunately came to realize that I'm in a deeper trouble:
What should I do if my provisional ends up being stuck between adjacent teeth? ( I the blunt end of my wax spatula to take it out at this point with 50% chance of success ) I know the solution to this would have been to remove and put back the provisional repeatedly before it gets too hard but it never works for me because I'm not too sure of the timing and sometimes my margins end up tearing if I take it out in its soft state. ( and I don't feel any heat from my matrix )

This sounds weird but it started happening since I've used my new Duralay set, which is the same as the one I used previously. ( maybe it's my technique, but I don't know ) The pontic of my provisional ends up stick hard to the gingiva of my typodont, requiring extreme force that ends up gingival damage. Does anyone know why this is happening?

What do you think I should do? My practical is early next week and I'll be sent to summer school if I can't pass this course. Please help me.

provisional ends up being stuck between adjacent teeth are usually due to too much excess acrylic or most likely undercuts and line of draw (3 unit bridge)
Undercuts: think of the Pyramid or the Eiffel Tower, that's how a crown prep should resemble (in an overly exaggerated way); tapering from cervical 1/3 toward the insical 1/3 (about 6 degree). Turn the Eiffel tower up side down, that's what an undercut looks like.
Now put 2 Pyramids or 2 Eiffel Towers together, that's how the abutments (for a bridge) should resemble. That's the line of draw. They should be straight up, tapering, and mirror images/parallel to each other. If either one of them is leaning toward a different direction then u don't have the line of draw; hence it wont be easy to get the provisional off.
To check for undercuts, u can use a cylinder diamond bur and lean it flat against the cervical 1/3 at the margin of the crown prep. If it's not laying flat onto the prep (or u can see a small gap bw the bur and the tooth close to the margin) then u might have undercuts.

When using a plastic stint, do not remove and put back the provisional repeatedly before it gets too hard. Use the left over portion acrylic to check the setting of your provisional, roll it and pulling it apart, when it starts getting stringy that's when u need to start lifting off the stint, not all the way up BUT only lift it off just slightly at one abutment then slightly off at the other abutment, then the whole stint, just so slightly on and off; repeat only a few times untill the provisional is hard and ready to be taken out.

Clean up the gingiva, cut away torn, hanging little pieces and vaseline it and all of the teeth well. Place some vaseline in the interproximal spaces will also help preventing the acrylic from getting in there. U can also use wax to fill in the interproximal spaces

Use just one type of temp material (jet acrylic, main material in clinic) and learn how to use it well, don't try out too many different materials, especially right before the practical.

Understanding the theories/concepts and hardworks in preclinic will pay off when u start clinic. Good luck!

btw, what're the teeth numbers for the bridge?

 

[Ron Burgundy]

In response to the original request, once you get your occlusion set, you can use a quarter-round bur to put back in your anatomy, but be careful you don't punch through the provisional. I've noticed that most of the professors are more interested in occlusion, margins, and surface finish more than anatomy...but that's my school...Anatomy really doesn't do much in the long run...that's my opinion...

An interesting choice for a stent would be to use a plastic-triple tray. Since it captures a bite registration while taking the impression, the provisionals I make from them normally need very, very little occlusal adjustment, and you can preserve a lot of anatomy that way...Buy the Schein or Patterson brand triple-trays, they are usually the cheapest...


Second, I like the bis-acryl stuff like integriy, however, don't throw away your powder-liquid stuff yet. According to Gordon Christensen (sp?) and Dr. Burgess from LSU, the stuff like Structur, Integrity, or what have you are usually only good for 1-2 units. Their flexural strength for multi-units aren't good, so that would be the time to dust off your Snap, Trim, Cold-pac, and make it the old-school way...other than that, use the bis-acryl because of the working time, and they release MUCH less heat than their powder-liquid counter parts.

hope that helps

 

[JesseBrad3]

Are students taught how to make out-of-the-mouth temporaries in dental school? I'll be starting dental school next fall, but at the office I work in now we always make a matrix using sli-tech putty on a cast. Once the tooth has been prepped, we take another impression (a green alginate) and pour it up in Gray rock (a quick setting plaster). Then we mix up some powder acrylic and monomer into a doughy-like consistency, setting it on the prep cast and placing the sil-tech/matrix over top and securing it in place with a rubber band. It all cures in about 5 min, then just pull it off the model and trim. All in all the process takes about 20-30 min, but it makes beautiful temporaries, and the dentist can be seeing other patients while all this is going on. Plus the cost of materials is relatively low considering how many provisionals can be made. He's a great dentist, so I assume there is a reason he makes his temporaries this way although there are probably quicker and easier ways to do it. Just wondering if anyone has ever heard of doing them this way.

 

[mike3kgt]

Are students taught how to make out-of-the-mouth temporaries in dental school? I'll be starting dental school next fall, but at the office I work in now we always make a matrix using sli-tech putty on a cast. Once the tooth has been prepped, we take another impression (a green alginate) and pour it up in Gray rock (a quick setting plaster). Then we mix up some powder acrylic and monomer into a doughy-like consistency, setting it on the prep cast and placing the sil-tech/matrix over top and securing it in place with a rubber band. It all cures in about 5 min, then just pull it off the model and trim. All in all the process takes about 20-30 min, but it makes beautiful temporaries, and the dentist can be seeing other patients while all this is going on. Plus the cost of materials is relatively low considering how many provisionals can be made. He's a great dentist, so I assume there is a reason he makes his temporaries this way although there are probably quicker and easier ways to do it. Just wondering if anyone has ever heard of doing them this way.

It's in our textbooks (Rosenstiel)! We use the direct stent method (acrylic via Cold-Pac) but would love to try out the indirect method... is it difficult to learn? I have gotten MUCH better at provisionalizing via stents but can be a REAL big pain the butt if undercuts engage and throw off the whole margin of the temp.

-Mike

 

[JesseBrad3]

I don't believe its difficult to learn. I'm not a dentist (yet anyway), but I'm doing most of the temporary work. I think in a practice it would be nice to have, b/c an assistant can be doing most of the work while you work on another patient or check hygiene. The only thing the dentist really has to do is place cord, take the impressions, and fine trim the temporary and place with temp-bond. It looks great in the mouth, and last a long time. Downsides are that it's probably more labor and time intensive, but as far as difficulty goes its just as easy if not easier. That being said, I havent had exposure to other temporarizing methods used, but would love to know what other methods dentists use in their practice.

 

[Supernumerary]

I don't believe its difficult to learn. I'm not a dentist (yet anyway), but I'm doing most of the temporary work. I think in a practice it would be nice to have, b/c an assistant can be doing most of the work while you work on another patient or check hygiene. The only thing the dentist really has to do is place cord, take the impressions, and fine trim the temporary and place with temp-bond. It looks great in the mouth, and last a long time. Downsides are that it's probably more labor and time intensive, but as far as difficulty goes its just as easy if not easier. That being said, I havent had exposure to other temporarizing methods used, but would love to know what other methods dentists use in their practice.

We're taught this at our school, but it just takes too long if you have a patient sitting in the chair. You have to get a good impression of the prep, pour it up, wait for the stone to set --- all before you get around to making the provisional. I guess this would be great if you had assistants to do this for you, but not when you're doing everything yourself.

Our prosth teacher told us that the only time we would probably use this technique is if a patient made an appointment to replace a lost or broken temp. That way you can make the temp from the cast before the patient even gets there. It's reseated and the patient is on their way in 10 minutes.

 

[DcS]

Are students taught how to make out-of-the-mouth temporaries in dental school? I'll be starting dental school next fall, but at the office I work in now we always make a matrix using sli-tech putty on a cast. Once the tooth has been prepped, we take another impression (a green alginate) and pour it up in Gray rock (a quick setting plaster). Then we mix up some powder acrylic and monomer into a doughy-like consistency, setting it on the prep cast and placing the sil-tech/matrix over top and securing it in place with a rubber band. It all cures in about 5 min, then just pull it off the model and trim. All in all the process takes about 20-30 min, but it makes beautiful temporaries, and the dentist can be seeing other patients while all this is going on. Plus the cost of materials is relatively low considering how many provisionals can be made. He's a great dentist, so I assume there is a reason he makes his temporaries this way although there are probably quicker and easier ways to do it. Just wondering if anyone has ever heard of doing them this way.

That seems like a big waste of time to me.

FWIW we use Integrity at UNC and I like the way it handles. Now I can make temps pretty quickly now that I've done a few on live patients!

 

[accu94672]

Thanks to all who contributed to my post.

Unfortunately, I bombed my practical really hard. I was marked down for almost every aspect of my provisional, let alone the occlusal anatomy.

The margins of my practical had cost me big time. When I pulled out my provisional, my margins tore up and there was no successful recourse for it. Whenever I tried "repainting" the margins with my acrylic, they ended up being so thin that they broke again. I lost too much time trying to repair my margins that I didn't get to do anything for the contours, pontic, contacts, occlusion, and the occlusal anatomy. And there were also potholes on the buccal and lingual surfaces. Anyways, I knew this was all a bad idea and had just decided to quit.

Nonetheless, have a great holiday and good luck in whatever you do.

 

[Energon]

hmm, ive been in the same place and there are many things that you can do.... ive been talking to psi young about the same things. PM me if you want to talk more. Bottom line, dont be discouraged, everyone goes through it, there is a learning curve and you will get better as time and practicals go by.

 

[tinker bell]

Accu,

If your margin is torn up like what you said, I think it's a little bit too thin. May be try to cut a thicker margin will help.
I always have to fix my acrylic margin. It never comes up nicely. Unless the sun shines upto 100F in SF. I mix a very thin, very runny mixture, and fill it around the margin. And wait for awhile, then take it out and carefully trim a tiny bit. Most of the time, it works just fine.
If I do it indirect, I take the acrylic, tightly occlude (on typodont or on a cast), immerse in hot water for 3 min, this will help it sets faster. I did this throughout my first year for crown test case, and second year for thebridge test case, and it works just fine. I always get high mark in making those temps. God bless me, I guess. However, I spent lots of time practincing before every single test case. The temp. of the room influences the setting time of acrylic as well. So, you have to practice right before test case, then it will go a little smoother.

I cut a little strip of boxing wax and press it in the proximal space, against the adjacent tooth. This helps a lot with trimmming, as there is not much excess.

First, I mix a thick, honey mixture, then fill it into the putty. Then wait until the acrylic lost it sheen, and put it on the prep. You should keep a little extra dough on hand to play with to check. When this dough becomes snappy, you take the temp out, if you do a direct technique (aka pt mouth), keep on putting the temp on and off, and use acrylic scissor to cut around, but not too close to margin, as you should leave a little room for it to shrink. If you are working on typodont or a cast, put the whole thing in hot water, then, trim it. I never have problems with high occlusal at all

About occlusal anatomy, I use a diamond bur to trim back the anatomy, so it shrinks, it's high, you have to trim it, but keep the anatomy in mind, and go around it. Make sure you press the tray on hell a hard, to get all the anatomy. I think all other posters have given all the tips you will ever need for acrylic. I'm not an acrylic expert, but I remember many sleepless nights I spent in preclinical lab to practice on both direct and indirect techniques. It's so frustrating. PM me if you still have questions.
Hope your next TC will be better.

btw, what year are you?