Provisionals

[Decan]

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I'm a second year dental student and I need some advice about provisionals, specifically protemp. We have practicals this semester where we have to prep and do a provisionals in ~2.5 hrs. For single preps I don't think it should be a huge problem but we have a bridge prep at the end of the semester and it takes me about 2.5 hours right now to get a good prep. Needless to say, I want to be able to do the provisional quickly. We have access to SNAP and protemp and it takes me a long time to get perfect margins with both of them. I like protemp but I find that it shrinks while I'm working on it and when I go back to the dentoform it doesn't quite fit right. SNAP is easy to work with but sets really slowly when I brush bead a margin. I never have any problems with occlusion or proximal contacts, but the margins take me a long time. I've tried marking them with a pencil and trimming to them but somewhere along the line I end up over trimming somewhere and then spend a chunk of time repairing the defect.

What techniques do you all use to make good provisionals FAST? Do you recommend one material over the other? For protemp, how long do you keep it on the dentoform and how do you know when to take it off (without locking it on your prep) ? What matrix do you suggest (vacuformed vs PVS vs exaflex)? Any general tips on getting good margins?

Thanks!

 

[HupHolland]

For bridges.. I prefer Jet (poly metylmethacrylate) vs. Snap (poly ethyl..)..... do you have access to Jet? Jet is a bit more prone in polymerization shrinkage, but is stronger.

Also, can you make a shell prior to the practical? This should save you quite a bit of time.. just a simple reline, trim the margins, tidy up the embrasures and polish. Also, you don't have to worry about the temp locking into embrasure undercuts.

For 2.5 hour practical... I would try to spend 1/2 time on prep, 1/2 on temp.

I prefer vacuform matrix when working w/ Jet or Snap, and a putty or PVS matrix when working w/ Bisacryl materials (Integrity, luxatemp).

Hup

 

[Decan]

Unfortunately, I'm not allowed to make the shell prior to the practical. Also, I do not have access to Jet. My biggest concern with protemp is it locking on the preps since we're not allowed to take the dentoform off once it is on the pole.

 

[caffeinehigh]

Why is it locking on? If the preps are undercut you should focus on that.

You can try dipping the stint full of SNAP in hot water for ~10 seconds before putting it on your preps. This will hasten the setting time, and potentially minimize shrinkage.

Either that or get some flowable and add to the margins of Protemp.

 

[armorshell]

Unfortunately, I'm not allowed to make the shell prior to the practical. Also, I do not have access to Jet. My biggest concern with protemp is it locking on the preps since we're not allowed to take the dentoform off once it is on the pole.

Anytime you make a temp you should ALWAYS relieve the internal to some degree to compensate for polymerization shrinkage to prevent the temp from locking on and to allow it to fully seat on the margins.

PROTIP: If it's a practical on a dentoform, after relieving the internal, seat the temp fully onto the prep prior to trimming the margins, and trim the margins ON THE PREP with finishing burs.

 

[Decan]

My preps aren't undercut...the reason its locking on is because the "gingiva" on the dentoform is awkward and the material wants to flow down the root of the tooth. I've been using vaseline to counter this so its not a huge deal anymore.

@ armorshell...thats a good tip...margins are my biggest problem. I haven't tried this before b/c I'm always nervous about ruining my finish line on the project but since I'll be doing this on practice teeth anyways who cares. 😀

Any other tips?

 

[UCSF2012]

Use impression putty.

Leave protemp in for 2:00 - 2:15 minutes. Then flick it off with an explorer. You can avoid margin problems by squeezing the putty faciolingually such that the putty adapts somewhat tightly with the margins. This should give you nearly perfect margins everytime.

I'd work on getting the prep time down if you're spending 2.5 hrs on it. You're losing time somewhere.

 

[armorshell]

Use impression putty.

Leave protemp in for 2:00 - 2:15 minutes. Then flick it off with an explorer. You can avoid margin problems by squeezing the putty faciolingually such that the putty adapts somewhat tightly with the margins. This should give you nearly perfect margins everytime.

Make sure you only squeeze once though, and maintain the squeezing pressure throughout polymerization if you do this, otherwise you can get some wicked wrinkles/bubbles.

 

[UCSF2012]

Make sure you only squeeze once though, and maintain the squeezing pressure throughout polymerization if you do this, otherwise you can get some wicked wrinkles/bubbles.

I squeeze on the adjacent teeth to avoid squeezing out too much temp resin. 80% the time, I don't have to adjust my margins.

 

[armorshell]

I squeeze on the adjacent teeth to avoid squeezing out too much temp resin. 80% the time, I don't have to adjust my margins.

No it's a good technique, and I do the same, just clarifying that if you squeeze and immediately let the pressure off, you can get wrinkling, distortion, bubbles, etc...

 

[HupHolland]

Why is it locking on? If the preps are undercut you should focus on that.

You can try dipping the stint full of SNAP in hot water for ~10 seconds before putting it on your preps. This will hasten the setting time, and potentially minimize shrinkage.

Either that or get some flowable and add to the margins of Protemp.

Remember, even if the prep doesn't have undercuts, the adjacent teeth naturally form EMBRASURE undercuts. This is something that people often forget and then blame the locking on due to an undercut in the prep!

Hup

 

[apaul]

Remember, even if the prep doesn't have undercuts, the adjacent teeth naturally form EMBRASURE undercuts. This is something that people often forget and then blame the locking on due to an undercut in the prep!

Hup

The way to fix that is to put rope wax on the adjacent teeth in their natural undercuts, then it cant lock in

 

[Decan]

Use impression putty.

Leave protemp in for 2:00 - 2:15 minutes. Then flick it off with an explorer. You can avoid margin problems by squeezing the putty faciolingually such that the putty adapts somewhat tightly with the margins. This should give you nearly perfect margins everytime.

I'll try that...a couple of questions though:

- should I wait 2:00 - 2:15 after mixing of the material or after the impression matrix has been on the preps?
- how much of the matrix do you fill? A friend of mine looked at the manufacturer's website and apparently they recommend filling the matrix halfway. I think that may not be enough.

Also, they recommend letting the material sit for 5 mins after its been out of the mouth but I'm afraid that the polymerization shrinkage will make the temp difficult to get back on the preps. Does anyone follow this rule?

Thanks for the suggestions everyone! Keep 'em coming.

 

[armorshell]

I'll try that...a couple of questions though:

- should I wait 2:00 - 2:15 after mixing of the material or after the impression matrix has been on the preps?
- how much of the matrix do you fill? A friend of mine looked at the manufacturer's website and apparently they recommend filling the matrix halfway. I think that may not be enough.

Also, they recommend letting the material sit for 5 mins after its been out of the mouth but I'm afraid that the polymerization shrinkage will make the temp difficult to get back on the preps. Does anyone follow this rule?

Thanks for the suggestions everyone! Keep 'em coming.

Filling it up all the way won't hurt anything, but you will have to spend precious time cleaning it out of embrasures, of the soft tissue, etc... If you're working on a typodont this sucks x100 because the material seems to bond to the "tissue."

Read my post above about internal relief. I don't see how working on a partially polymerized provisional is going to get you better results in the long term then just doing a little internal relief to make sure you can seat the thing.

 

[UCSF2012]

I'll try that...a couple of questions though:

- should I wait 2:00 - 2:15 after mixing of the material or after the impression matrix has been on the preps?
- how much of the matrix do you fill? A friend of mine looked at the manufacturer's website and apparently they recommend filling the matrix halfway. I think that may not be enough.

Also, they recommend letting the material sit for 5 mins after its been out of the mouth but I'm afraid that the polymerization shrinkage will make the temp difficult to get back on the preps. Does anyone follow this rule?

Thanks for the suggestions everyone! Keep 'em coming.

2:00-2:15 after the 2 polymers touch. Fill it all the way, fill it half way...depends on how much reduction you did. Just as long as it covers the entire restoration. You can even mix the 2 resins on a mixing pad if you want. To save cash.

You can also use composite resin as a temp. Adjust it as necessary before you light cure. When you light cure from the facial/lingual, it doesn't cure the mesial/distal well, so it doesn't lock the temp in. Then you cure the mesial/distal independently.

 

[achtung6]

My preps aren't undercut...the reason its locking on is because the "gingiva" on the dentoform is awkward and the material wants to flow down the root of the tooth. I've been using vaseline to counter this so its not a huge deal anymore.
Any other tips?

If your temporary bridge locks on the day of the practical.....you are undercut or you nicked the adjacent tooth. The gums on your typodont have nothing to do with it. Like someone mentioned, all these materials suffer shrinkage, even more so if there is a lot of material to begin with, like in a bridge. Also, have an excellent putty matrix made in advance for your bridge and cut out the interproximals on the putty otherwise those areas on your provisional bridge will be too thin and it will break on you. Remember, teeth in the typodont have no give as they do in the patient so it cannot lock in any way.

 

[armorshell]

If your temporary bridge locks on the day of the practical.....you are undercut or you nicked the adjacent tooth. The gums on your typodont have nothing to do with it. Like someone mentioned, all these materials suffer shrinkage, even more so if there is a lot of material to begin with, like in a bridge. Also, have an excellent putty matrix made in advance for your bridge and cut out the interproximals on the putty otherwise those areas on your provisional bridge will be too thin and it will break on you. Remember, teeth in the typodont have no give as they do in the patient so it cannot lock in any way.

As mentioned above, it could be locking into the proximal "black triangles." There are many different brands of typodont, and some, like ours at UoP, looks like they have had 4 quads of 5mm crown lengthening with APFs.

 

[Decan]

The gums on your typodont have nothing to do with it.

I respectfully disagree...our professors have repeatedly told us to use copious amount of model release agent or vaseline on the areas the material may flow into. They even said to unscrew the teeth and place vaseline in the socket, and then screw the teeth back in (for protemp, not SNAP).

Thanks for all the replies! I'll practice and try to incorporate all the ideas. If anyone has any other helpful tips, keep 'em coming! Your help is appreciated.