Bridge prep advice

[Decan]

I have a competency in a few weeks and we have to prep 12-14 in 2.5 hrs. #12 needs to be a metal ceramic prep and #14 is a full gold crown prep. Given enough time I can crank out a good prep but during a competency time is the enemy. We also have to create a provisional for the competency so our professors recommend that we should have the preps done in 1.5 hrs. I can get the preps done in time but they usually don't turn out as well as I would like (especially the premolar).

How would you approach this prep? What burs do you use? Any recommendations on how to cut down the time? Any help would be greatly appreciated!

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[panino]

I would spend one hour on the prep and the rest of the time on the temp. I find that it takes longer to refine the temp than the prep.

I use the diamond half chamfer and the diamond shoulder. I always start on buccal and save occlusal for last - just personal preference. Oh I leave the two phase reduction until the end too.

If they let you, make the matrix first. If not, it's no big deal either - a silicone putty matrix is pretty fast to make.

And practice lots!

 

[Streetwolf]

I do the opposite... occlusal first, then the rest.

I'm not sure what burs you use. I do depth cuts with a 556 just shy of the correct distance. If you need 2 mm reduction I'll do about 1.7 mm. I know that when I start nit-picking and smoothing at the end, it will end up at 2 mm.

I use 856 diamond to smooth the occlusal.

I use the pencil diamond to break interprox contact. In your case you'll only need it between 11/12 and between 14/15. For the edentulous area I treat it the same as a B/L axial wall.

I just reduce B/L with 877 diamond chamfer to start (878 possibly afterward). For the buccal I'd then use the 847 (I think that's the number) shoulder diamond. Create the 2nd plane of reduction at this point on the lingual with a chamfer.

Finally go back and make everything look nice and smooth it out. Cusp tips should be rounded. Make sure your finish line is smooth and is even.

Also make sure the M/D has appropriate taper both within one tooth and relative to the other tooth. Remember to close one eye to verify this. Double check occlusal reduction.

Your prep should be quick - about 1 hour. Is this on the bench or on a pole? The pole might be longer.

The above poster is right... the temp can take time.

Good luck.

 

[laundry]

Bench top, the preps should only take about 35-40 min... The great thing about bridges is that you have only 2 interproximals to worry about, not 4 😉

Here's what I do. Reduce 14 from DB interproximal all the way around to DL interproximal, then reduce occulsion, which will make distal interproximal access easier. For 12, do the same (MB to ML). I use 856-016 for everything (love that bur). If you have time, you can go over everything with a carbide - this makes the prep super smooth and as a result easier to temp.

What do you use for temp material and impression material? We use protemp, and that stuff takes like 10 min from start to finish. If you use acrylic, I highly suggest investing in protemp.

good luck 👍

 

[Decan]

The preps must be done on the pole....I've been practicing a lot and I've pretty much gotten the time down to an hour and a half. For the temp we're allowed to use anything we like (SNAP or protemp). We're also allowed to have shells...I made the shells in acrylic. During the practical I'll just reline it, refine the margins with flowable, and hopefully everything works out well!