NERB Candidates please read

[1jenn32]

Hello all. I'm here for some advice/suggestions from anyone who has taken or will be taking the NERB, or anyone who has participated in a Mock Board for this exam.

The candidate manual talks about fabricating a "fixed partial denture" out of liquid/powder acrylic. I know it's not going to be as simple as making a temporary bridge, like you could do clinically on live patient. (IE-yes, I will have to use the vaccum-mixer, pour dies, wax a pontic tooth into my model, maybe make a vacuum-formed stent for this "fixed partial denture.")

Sssoooo....If you could kindly describe for me the exact procedure you used/will be using for this portion of the exam, I would much appreciate it!

I have been out of academic dentistry for 5+ years, and I am taking the exam in a completely strange clinical setting (OSU.) (Plus walking back into a dental school kinda gives me hives!) Every dental school has their own way (the "right" way ) of getting from start to finish on any given procedure. Can you tell me your way?

Thanks for your help!

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[UBTom]

If you can get nicely adapted margins using whichever method you prefer, you are good to go. I seem to have best luck with the indirect method-- Curing the provisional on a Jade Stone die of the preps, then breaking out the provisional by destroying the die after the acrylic has set.

You will have 7.5 hours to do the preps, the provisional, and the endo exercise... Considering that you already have 5+ years of experience, you should be OK!

Luck.

 

[gryffindor]

To save your time...

You don't have to wax up a pontic. You are allowed to bring the pontic in with you, but nothing else (like no preformed templates can be brought in). A good suggestion for the pontic is to get a #20 typodont tooth that fits the Columbia typodont and cut the stump off and adjust it to fit in the space.

You also don't have to use the vacuum mixer if you can get adequate stone pours from hand mixing alone. Again, saves time because then you don't have to set up and clean the vacuum mixer.

You could use a vacuum formed stent for the template. I am opting to use a putty template because I save some time this way. With the vacuum formed stent, you have to take an impression of your typodont with the pontic in place, pour it up in stone, and then make the stent. With putty, you can skip the pour up step since you can just make the putty template right on the typodont with the pontic in place.

Also, you don't have to make the bridge out of powder/liquid. You can use whatever temporizing material you want, you just have to supply your own stuff. I have a very limited knowledge of temporary materials for fixed, but you can use something like Integrity (stuff that comes out of a gun) to make the bridge. I don't plan on using Integrity b/c it is way expensive and I'd have to buy it on my own. Acrylic (powder/liquid) is way cheaper and the school will provide it for us, but I know people who swear by Integrity and loathe acrylic. Keep in mind that whatever material you use, the bridge will be shipped to DC and not graded till weeks after your do it, so material properties can have a role in your bridge lasting through all that trauma till they get around to grading it.

Good luck, and keep us posted on your experiences having been in the "real world" for sometime...

 

[dudelove]

Be careful using materials like integrity, protemp,etc. They are more brittle than the acrylic you most likely use. If I recall, when I took the NERBs, the only way they protected the bridge was to put it on the typodont and stick a little bubble wrap in between. Also, they will give you fibers(red or black) that you need to add to the bridge to make sure that you made it that day. You don't need to add a lot of these fibers, only enough for some of them to show up. They do change the working properties of the material slightly. I had crap luck using the acrylic that the school provided so I went out and bought Alike acrylic which I swear by and still use in private practice. Good luck!

 

[MAXFAC]

Here is the technique I used,
1. I brought in pontic # 20 from columbia teeth with root cut off.
2. Lubricate the two abutments and edentulous area with KY Jelly took quadrant alginate impression.
3.Poured up the impression in die stone. left it to set.
4. Prepare abutments # 19 & # 21.
5. Take final impression of prepared abutments with alginate again.
6. pour it up in MACKII silicon die material. by this i can evalute my preps better and fabricte the provisional indirectly without running the risk of breaking it or the abutments if it got stuck in the mouth.
7. I have the pretreatment model in die stone is set now I can add the prepared pontic and attach it with wax. then take a putty impression, by this I can get several good putty impressions if the first don't work i have a model.
8. I used ALIKE acrylic, but you can use GC Light cure acrylic , very good for marginal adaptation. don't use Bis-acryl not good for NERB it is brittle and you can't add the fibres provided by the NERB.
9. Put the ALIKE in the putty and apply it to your MACK II silicon die till set.
10. Trim and adjust, if you have open or short margins or open contact you can add it directly in the typodont after lubrication, using salt and pepper Alike but i found GC light cure acrylic to be amazing for marginal adaptation since you can add it adjust it till it is good and then light cure and you don't have to wait for it to set.
11. For polish I used all kind of polishing but at the end I give it a final gloss with PALASEAL which is unfilled resin for glossy finish also light cure.
My two cents and Best of Luck Doctor.

 

[gryffindor]

Nice post MAXFAC, it's interesting to read what others will be doing/did. I hadn't thought about taking the alginate with the pontic in place and making the putty off that pour up.

I think this is what I'm gonna do -

1. Hold the pontic in place with the real soft blue ortho wax, take like 2 or 3 putty templates of it.
2. Prep #19 & 21 - axial first, then occlusal.
3. Take 2 PVS quadrant impressions of the preps and pour both up in green Jade Stone.
4. While the stone sets, do the endo excercise.
5. Remove the stone preps from the impressions, trim the excess stone off them to seat flat on the counter.
5. Lube the stone preps with Alcote (separating agent).
6. I will be using Jet Acrylic to make the bridge. So take one of the putty templates, trim it to fit the stone pour. Add powder to the cup with your fibers so you don't forget to use them. Fill the putty template starting with a layer of powder in all 3 teeth, followed by a layer of monomer liquid and so on, layering the 2 components till you fill the entire template. Remove the excess out of #18 & 22 and set the template onto the stone pour.
7. While waiting for the acrylic to harden, pour up the 2 PVS impressions again in green.
8. Acrylic is now hard, take off putty template and take the stone pour with the acrylic on it to the model trimmer. Trim off all stone distal to #19 and mesial to #21 just shy of where your contacts on #19 and 21 are (don't trim your contacts!). This way your contacts will be exactly where you want them, just make sure to mark them so you don't trim them away.
9. Get the acrylic off the stone model. Use the high speed to get the stone out if any of the preps break off. Trim the excess and interproximal with e-cutters and interproximal discs and whatever else you want to use. Use the extra green stone pour ups you have to make little individual dies of the #21 and #19 preps to trim the margins real close in the interproximal areas and get rid of excess flash. Use another green stone pour up to make sure you have a good path of getting the bridge on and off without breaking off the preps.
10. Once you can get the bridge on and off with ease, put it back on the typodont, paint monomer on any deficient margins, and apply a runny mix of acrylic into the margins. Use an instrument to remove as much excess as you can to get it real close to the margin.
11. While waiting for the margins to set on the typodont, adjust occlusion. When the margins are hard, take it off the typodont and adjust any excess a tiny bit if necessary.
12. I wasn't planning on polishing the bridge and making it shiny since that particular criteria says it just has to be free of scratches and voids and have good occlusion to get a I or II. It doesn't have to look pretty, just be smooth.

Let's hope this works on May 5th...

 

[1jenn32]

..I had a couple of minutes to look over your suggestions so far. These are exactly the kinds of things I am interested in reviewing. THANK YOU and I'll be spending some more time on this thread very soon....