Repairing Complete & Partial Dentures
2014
see the video: http://www.learnerstv.com/video/Free-video-Lecture-4819-Dental.htm
Welcome to the University of Michigan Dentistry Podcast Series, promoting oral health care worldwide.
So, what do we want to look at today in terms of repairs? What do we do if we have a fractured denture? Has anybody had a broken denture in half that they’ve had to deal with before? So, it will be review for some of you. A fractured or a damaged tooth. We’ll also go through modification of a temporary partial denture or partial, post dam modification, and clasp repair.
So, if we looked at a fractured denture first, the way you usually repair these things is either with polymethylmethacrylate, a self-curing acrylic, or we can use the pink colored triad material. Here’s a little example where there was a little bit of a flange broken off the denture, but it would exactly be the same procedure if the denture were broken in half right down the middle. So, the fact that, in this case, there’s a corner broken off it, the technique is exactly the same as if it’s broken right down the middle.
Now, sometimes what makes this process more difficult, we just had one in our clinic last week, when polymethylmethacrylate breaks and a patient brings it in, the two pieces were the fracture plane is an extremely crisp and clean fracture plane. So, when you put the two pieces back together, there’s really no question whatsoever about how they fit because the two pieces will mate very perfectly. There’s one exception. Anybody have any idea what the exception is?
The patients will, oftentimes, try to repair their own denture with a glob of superglue, and if patients put a big glob of superglue on these mating surfaces, superglue will actually melt the plastic a little bit. With patients, they’re just like dental students. If a little is good, a lot must be better, and a whole lot must be a whole lot better. Not true.
So, then, what happens is the patient comes in and these two pieces that would originally have mated together very nicely no longer fit, and sometimes you have to go to plan B, C, or D. The hope is when patients come in, it’s been broken, they haven’t tried to fix it with superglue, and if you take literally one drop of the real runny superglue, put it on one of the mating surfaces and hold just the two pieces together for about 10 seconds, it will weld them together. That’s not your repair. That’s not your repair.
The only reason you stick things together and the thing I hope will show for this particular example is doing some sticky wax. So, that’s why one person is holding it together real carefully, and someone you trust not to drop the sticky wax on your finger or thumb drops some sticky wax on. You can accomplish this same thing with one drop of superglue on the fracture plane and go ahead and tack it together.
So, now that the two pieces where the fracture has occurred are tacked together, what we want to do is pour some sort of an index on the inner aspect of the denture. So, what we do in this particular case because it happens to be a quick setting plaster index. Up the clinic, the stuff that you folks would have would be mounting plaster. So, if you make a creamy mix of mounting plaster and put on the inside of the denture, it will basically make an index so that those two pieces of plastic, when they’re fractured apart again intentionally to do your repair can be repositioned so they’re in the correct orientation.
Now, the indices that we make may be made out of plaster. They may also be made out of PVS, and they may also be made out of alginate. You’ll see examples of both of those later on. So, here we have the index made, and, again, whatever the index material is inside your fractured denture, like I say it happens to be quickset plaster, it could be PVS injected on the inside. I’ll usually use medium or heavy body so you get a rubber model. It’s an expensive model, but depending on the situation, it can be worth it. You can also use alginate.
So, now that we’ve got the index made, then if we clean off our sticky wax, if this thing had one drop of superglue in this wax, you can tax the denture off and intentionally break these two pieces apart again. So, here, you’ve got your two pieces. The repair is not done, but they now fit on an index.
So, what we then do is bevel the oral the surface. That is, bevel this fracture so that when we put the repair acrylic in here, it has a broader area of contact. So, if you look at this thing on the side, you’ll see how on the tissuemost aspect of the fracture, we didn’t cut it apart a lot, but we beveled both sides back on the side that faces the tissue. There’s a little bit of opening here, not a problem because the index we poured on the inside of the denture captured the shape of the tissue surface in this.
So, we bevel this back for two reason. One is it freshens the acrylic because when the acrylic has been in contact with spit, some of spit microscopically soaks into the surface of the plastic and contaminates the plastic. So, if you put fresh repair acrylic on that contaminated surface, it doesn’t bond as tenaciously as it does if you cut that surface back a little bit, exposing fresh polymethylmethacrylate that’s never seen spit. So, when you go to put your repair medium on there, it tends to stick better. It bonds better. Then, the reason that you bevel back from the fracture line is, can you see, you have a larger surface area for your repair material to grab onto.
What we do in this case is if we’ve got some self-repair acrylic, and this stuff is available at the dispensing desk. It’s a self-cuing pink repair acrylic. So, it’s the usual thing, a dab and dish of liquid, a dab and dish of powder if you’ve got the plastic dab and dish liquid and powder. Moisten the fractured surfaces with some monomer on a Q-tip. I tend to like these sable brushes with the black, wooden handles as opposed to the little throw away nylon brushes they want to try to give you because the nylon brushes aren’t nearly as good for picking up small increments of repair acrylic.
One can also the repair with the triad material. I don’t like the triad material as well because it bonds pretty well, but I think the triad material, being a composite, is quite brittle. So, for those of you that have made trays or record bases from triad, you’re aware that you drop them on the floor, they tend to shatter. So, I think in function, the polymethylmethacrylate repair, in my experience, is a little tougher. It tends to hold up better and not refracture. This is particularly the case for maxillary denture, for example, when it fractures down the midline, and we see that fairly commonly.
So, in this situation, we would have freshened, cut back the surfaces with a little bit of monomer. We put some bonding liquid on the fracture and, then, take some of the pink repair triad and press it under nicely. What we’re doing up here is having a little dab and dish of just regular acrylic monomer. What works well for that is if you dip in a little instrument to just smooth this material out. It doesn’t increase the bonding. It’s just a handy lubricant to smooth that material out.
Then, you put you air barrier coating. This stuff, again, prevents oxygen from coming in contact with the surface of the triad as it’s curing so that when it’s fully cured, this air barrier coating, the large jug of material back there that’s a big jug of clear liquid snot, it’s not the Vaseline. Question.
The particular triad, there isn’t. So, if you have a dark characterized denture for an African American patient or another patient, the triad itself that we have doesn’t come in different colors, but if you would take the powder liquid, the polymethylmetharylate, if we know we’ve got a repair coming in, if we call Ward Dental Lab or Sharp Dental Lab, they have some shaded or toned repair acrylics that we don’t carry here.
The acrylics we’ve got in stock here is just your standard light fibered pink, and if you need a darker shade, it’s not that it doesn’t exist. We don’t typically stock it, but when we’ve needed it in the past, if we just call the lab where the denture’s made, if we call Ward or Sharp, “Could you send us some of your characterized repair acrylic?” They send us a little bit of the powder, and the powders work with any of the liquids. So, the fact that we don’t need to get any special liquid, our liquid works just fine with the powder. So, if you’ve got one coming up that you know is a shaded acrylic, then just call the lab and get some of equivalent shade in a self-curing acrylic. Yup.
Air barrier coating’s on. It goes in the triad ovens. The powder comes and you shade it. We shape it back with an acrylic bur. We pumice it, and so what we’ve got here is the repair once it’s completed. It’s pretty much undetectable from the original.
A question was brought up, and it’s a very salient question if your patient has a characterized or anything other than light fiber pink plastic bases on their dentures. The stuff we normally stock at the desk doesn’t match. So, if you know you’ve got one of these coming in or if you’ve seen it, then, go ahead and get a hold of Ward or Sharp, and they’ll send us a small amount of the shaded repair acrylic to do the repair.
So, what if we’ve got a patient that fractures maxillary denture, but it’s not broken in half? The patient basically is fractured here and goes across here. So, we’re going to do the same thing. Some people say, “What if I just pour a little acrylic right on that fracture line? Won’t capillary action suck the acrylic into that crack and heal the space.” Short answer: No. You don’t get enough bonding on that. It refractures again about the time they get to the parking structure.
So, if I’m going to go ahead and cut a little channel along this because isn’t broken in two halves. Again, I want some sort of a matrix so when pour the acrylic in there to do the repair, it’s not running all over the inside of the denture, and that’s where we go ahead and inject medium body PVS or heavy body PVS in the inside of the denture. The beauty of using some sort of a rubbery material is you don’t have to block out any undercuts. You just squirt it everywhere, no blockouts. Let it set up, and it comes in and out of the denture just fine. So, medium body PVS is just fine for that.
So, you can see we’ve made that little index, and when we take the denture, we pull this from the inside of the denture. This is what the labial aspect looks like. So, this represents the inner aspect of the labial portion of the denture. So, what we do now is go ahead and take a small acrylic bur and go ahead and cut that plastic out of there completely, beveling it toward the tissue surface.
You put your index back in. So, this now captures what the inner aspect of the denture looked like, and then, again, a dab and dish of liquid, a dab and dish of power, dip in the liquid, pick up some powder, and just paint these areas in. Again, if we get some from the dental laboratory, we don’t have these ate the desk anymore. The companies do make kits if you have this in your office. They give you different shades of self-repairing acrylic with a common bottle of liquid. So, what we typically do is use self-curing acrylic.