Diagnostic Wax-Ups

In this case study, we introduce to you a new concept, "minimal-prep veneers.," As part of this, we are going to take a look at the Diagnostic Wax-Up technique, which you can use as a guideline for where to prep and how much to prep on these minimal-prep veneers. We are going to use a combination of minimal-prep veneers, and some traditional fixed crown & bridge in the posterior to replace some missing teeth.

You can see, as we look here from the occlusal view, that we have some areas of the teeth that are sticking out a little bit to the facial, like on one of the central incisors. We're going to take a better look at this in a minute. We also have missing teeth on the posterior, as well as some other work that needs to be done.

Rather than doing a full arch of crown & bridge, we're going to do a crown & bridge in the posterior and minimal-prep veneers in the anterior. In order to get a better idea of where we're going to need to reduce in the anterior, let's take a look at the study model.

Here's a look at the preoperative model: the teeth we're concerned with are teeth #6-11, the ones that will be receiving the porcelain veneers. With the advent of no-prep veneers, and certainly minimal-prep veneers, we like to prepare the least amount of tooth structure possible.

We know that if we can keep most or all the preparation in enamel, we're going to get better bond strengths when we go to place the veneers. We'll also get less post-operative sensitivity and fewer de-bonds down the road. Botton line: Anytime we can keep everything in enamel, that's the desired path to go down. Certainly, with no-preps, we have everything in enamel, but we look at a mouth like this and we can see there's an area here.

We're looking for areas that stick out to the facial – these are what we call "facial limiting factors," and this impairs our ability to get a good esthetic result. Namely, we're trying to match the Diagnostic Wax-Up here; that wax-up was done after the lab went and prepared some of these areas. (We'll take a look at what the laboratory wants us to do in a moment.)

But as I look at this, I can see there's an area here sticking out of the facial. As we look at tooth #9, I can see there's some area in the distal.

Tooth #7 looks like it might be sticking out a little bit to the facial. And tooth #6 & #11 look to be maybe in pretty good location. As I look at this, I am planning where I might need to reduce. The more important thing is where the lab thinks we might need to reduce. So, let's take a look at that model.

Here's the study model back from the laboratory. These are the areas (marked in red) where they did some adjustment before doing the Diagnostic Wax-Up. The Diagnostic Wax-Uup was not done on an unprepared model. It was done on a prepped model, and you can see the areas where they feel we need some reduction. And you know what? It is pretty minimal. It is certainly a lot less reduction than the way I was taught to prepare veneers.

There's nothing on tooth #6. Tooth #7 has a small spot on the incisal third, on the distal half of the tooth. Tooth #8, the entire distal third from incisal edge almost to the gingiva –we'll say all the way to the gingiva– needs a little reduction. On tooth #9, you can see the distal half again. And tooth #10 is untouched.

The mesial third, just enough to hide the contour on this cuspid, needs to be reduced slightly. As you refer to the original model and look at where the lab marked, you get an idea of how much they reduced. They know that we like to stay with enamel wherever possible.

I will need to go in and make modifications to these four teeth. Once that is done, I know we'll be able to achieve the Diagnostic Wax-Up. And once I take an impression of these reductions, the lab will be able to provide me with porcelain minimal-prep veneers that look like the Diagnostic Wax-Up (which both the patient and I have approved).

At this point, the patient has approved the Diagnostic Wax-Up. We discuss the case, and I point out a few things. I tell the patient there is one more thing we can do: I can show her what the final restorations will look like in her mouth before we even start.

You too can do this at the prep appointment or before. As you see, I have the Diagnostic Wax-Up and I'm using a half-Hollenback to clean up the gingival area. Sometimes on a Diagnostic Wax-Up, these areas aren't that sharp and you really want to go in here to make sure you define the gingival margin and the embrasures with a sharp instrument like a half-Hollenback– the temporary technique is going to work a lot better if you do that.

I go ahead and make that putty wash matrix for the temporaries, but you'll see I use it twice – I'll use it before we even start prepping. We mix up some impression putty here so that we can take an impression of the Diagnostic Wax-Up. And then we're going to use our bisacryl temp material to actually give the patient a preview of what her restorations are going to look like. We typically do this at a consultation appointment, not the prep appointment; it just depends on how it falls together.

Doing this will provide the patient with greater confidence about the esthetics of the final veneers. This step can also help the patient decide if he/she wants to commit to treatment. The patient has already paid for the Diagnostic Wax-Up; if she opts to abandon the treatment, we won't be stuck with the Diagnostic Wax-Up fee. For me personally, that's very important because, in my career, I've been stuck with Diagnostic Wax-Ups that the patient didn't pay for.

Of course, once the patient pays for it and has the treatment done, the cost of the Diagnostic Wax-Up is applied to the overall fees, so it's not like it's something that doesn't get used. And as you can see, it's going to get used here, and it's also going to be used for the temporary itself. The Diagnostic Wax-Up is more than just a sales tool (at least in the way that I like to use it).

We place the putty onto the Diagnostic Wax-Up after rolling it into a hot dog. We wait for it to set, about four or five minutes. It may take longer out of the mouth because we don't have the increased temperature of the oral environment.

So we let the putty set. As you can see, I'm using a scalpel here and just carving off the excess where it went down to the land areas of the model.

We want to go approximately 2 mm past the gingival margin. However, if we leave this mass of putty material here, it's going to be difficult to put back into her mouth. She'll never be able to get her lips down around it.

We trim off as much of this as we can in order to ensure the putty wax matrix is completely set.

I'm trimming a little bit off the back of the putty matrix for teeth that are not involved in the treatment. It tends to become less accurate when we get back to the soft tissue distal to the second molar. Because of this, we'll trim the putty anywhere we don't need it.

You can see I'm thinning the putty matrix facially, as well. This makes it easier to deal with, easier to get in and out of the mouth – we just don't need a huge mass of material. So, use a Bard-Parker, scalpel or whatever tool you choose, to trim the putty matrix.

Now that I've trimmed it, I'm re-lining it with light body material.

We squirt that right into the putty matrix, and we're going to reseat this back onto the Diagnostic Wax-Up. And this light body material is going to go into all those areas where we went in to define the gingival margins and the embrasures with our half-Hollenback. We let that set for about four minutes.

Take it out, and we're going to trim any excess wash material so that the visible wash material is confined to the putty wash matrix itself. We have a very nice impression of the Diagnostic Wax-Up.

Next, we mark the midline – you go to put this in place, it gets a little difficult to make sure it's in the right place. You can still do it, just makes it easier.

Now we're going to use some Luxatemp® bisacryl temporary material. We use "BL", the bleached shade. For minimal prep veneers, the bleached shade works really well. I've tried to use an A1, for example, when I thought we were going to do an A1, but these temps are so thin that you see a lot more of the tooth showing through.

For minimal prep cases, or anytime I mock up a case like I have here, we always use the bleaching shade. It takes the whiteness of the temporary material and sits on top of the tooth to provide a desirable shade.

You push the putty wash matrix all the way down with the bisacryl inside, just clearing the lip to ensure that it is seated all the way. That is one of the reasons why we thinned the front of that putty wash matrix before we started. We got our midline marker making sure it's in the right place.

We are going to wait a good three or four minutes here for this to completely set and lock onto those teeth.

We have transferred the information from the Diagnostic Wax-Up to the patient's mouth – and we got some excess in the lingual I'll take off. She can now see what her veneers will look like. On the areas where the teeth are too facially prominent, we're not going to see exactly what it will look like until after the prepping is done.

But this is a neat way, especially for somebody with diastemas, to get an idea of what the improvement will look like. It's one thing to look at the Diagnostic Wax-Up, but it goes to another level when you can actually see in your mouth what it's going to look like with the diastemas closed.

Some dentists freehand this technique with composite – that just takes too long for me to do. My dental assistant pops off the putty matrix using a gold knife. It was just mechanically retained; we didn't put any kind of bonding agent or anything on, so that it won't stick to the teeth.

Here we use PFG Lite Gel (formerly Profound Lite), so that the patient won't feel the needle on these minimal-prep veneer preparations.

It's really up to you and the patient to decide whether you want to use some local anesthesia. Needle-phobic patients usually say, "No, let's try it without." We use a lot of light pressure with the new diamond – very coarse diamond – so we take off as much tooth as we can without generating a lot of heat. However, this patient is not needle phobic and wanted to have anesthetic so she didn't have to worry about feeling anything, which is fine with me.

Here's a comparision of the prep guide model from the lab to the patient's teeth. And I always kind of hold this here – once I'm looking at the teeth – to get an idea of where I need to reduce. Many times, my bracket table sits right over the patient's chest. You can either set the model on the patient's chest or preferably on the bracket table so that you can reference this as you make these markings.

You know, how much the lab has actually reduced is just an approximation when you actually go in to reduce. Again, you can see I am using a large diameter bur. This is going to reduce a lot of tooth structure at one time; it's going to be nice and smooth on the tooth.

The thinner the bur, the more the bur wants to kind of dive into the tooth and create grooves. The only thing we are trying to accomplish is eliminatination of proximal line angles and the portions of the tooth that are sitting facial to our ideal arch form.

So, this is rather straightforward: Follow the model. If anything, reduce a little bit more than you see on the model. Laboratory technicians never complain about having too much room – I can tell you, because I spend my whole day with laboratory technicians.

The only complaint we hear from laboratory technicians is not having enough reduction. So, it depends on how the patients feel. Technicians understand that, on a no-prep case, they have to work with what's there. And they're not always happy about that. But on these minimal-prep veneer cases, where we are going in and guessing – basically, it's a matter of taking off the tooth structure, looking at the prep guide model, and seeing if you've eliminated that. Often times, I use a photo mirror to look down from the incisal edge of the tooth to see if I'm eliminating those facial limiting factors.

In addition to the minimal-prep veneers, which is the focus of this case, the patient also wanted to fix some bridges done on her posterior teeth to eliminate spaces. We'll briefly go through that.

There's the round bur, the 801-021 bur, that we use as part of the Reverse Preparation Technique. And that's really a great look because we don't have an adjacent tooth and what that round bur does – you can see, it really creates not only a gingival reduction but the margin at the same time.

In a case like that, where you have a tooth out there in the middle of nowhere, where you have no adjacent teeth, we can actually use that round bur all the way around those teeth.

We are placing 2 mm depth reduction holes in the top with the MADC-020 bur. If I don't put these 2 mm holes in the teeth, I can almost guarantee you that I will not reduce 2 mm – and that's after being a dentist for more than 20 years and thinking I know what 2 mm looks like!

It's just part of human nature: Once you start to reduce a tooth with a diamond, you can never really tell how much you've reduced. And most of us, being conservative by nature, try to prep the least amount possible to get the desired result. But, all too often, we don't get the desired result when we get the restorations back from the lab because we have not, in fact, reduced enough. So, we put 1.5 mm holes in the axial surfaces.

Again, I use my favorite bur, the 856-025, for reduction. With the exception of breaking contacts (when necessary) and placing depth cuts, almost everything is going to be done with the 856-025 bur (unless it's an anterior tooth, and then we'll go ahead and use the football bur on the lingual surface, but these are posterior teeth).

The depth cuts have been made, and I will go ahead and make the cuts down to the level of the depth cuts. Those 2 mm holes I placed with the 856-025 bur, working it back and forth, and I love this bur. It's such a great workhorse bur. It's a nice coarse bur, and it does a good job of cutting through, does a great job of refining the margin as you go down to blend the axial planes and combine your other depth cuts with the gingival depth cut that you originally did with the round bur.

I love the large diameter of the bur. It sits well on the tooth. If you told me I can only practice with one bur for the rest of my career, I think it'd have to be an 856-025 like this. It can do almost anything – it's just extremely versatile – with the exception of lingual reduction on anterior teeth.

Once we have all the depth cuts in place, it's pretty much just a race against time to see how quickly we can get the rest of the tooth structure off. These preps are starting to take shape now, and we're just going around and blending some final planes here on this bridge. We're leaving that buckle margin super gingival, as you can see here – it's not a critical esthetic area.

The patient has had some recession over there and really no reason for me to drop that all the way down to the gingiva and get a long, long wall for that bridge that's going to be a little more difficult to seat, a little more difficult to avoid undercuts, and all those kinds of things. If I give my laboratory technician a nice super gingival margin to get a good impression of it, we're going to get a great-looking margin opening that's going to be nice and closed. And because it's in an esthetic area, I don't see any reason to go down any farther.

We take the BioTemps®, which were fabricated for us by the lab, and try them on over the bridge to ensure a passive fit. And you can see that we do have passive fit. In fact, it rocks around a little bit, which is fine because we're going to reline that in just a minute.

Before we prepare the posterior teeth on the other side, we're going to take a bite registration. So we're squirting bite registration onto the prepared teeth and asking the patient to close all the way down.

The maximum intercuspation – squirting a little extra bite registration material there. You do not want to take a bite registration of the entire arch for a case like this, just on the prepared teeth. This is the Capture® bite registration material.

The hard bite material sets in about 60 seconds, so we can pop that out. It will be trimmed back by us or the laboratory so that only the occlusal third of the preparations are sticking into the bite registration, and only the occlusal third of the opposing teeth are sticking into the registration as well.

We've now relined this with our acrylic material, and we're pushing it down into place on the preparations. And this is when the temporaries are really going to fit well afterwards. This is one of the great uses for BioTemps – it's a really nice-looking provisional bridge. BioTemps are very strong and its wire reinforcement, made from hollowed out dentured teeth, provides very nice esthetics as well.

We push this down into place and wait for the acrylic to go through its reaction, as we pump it up and down to avoid any undercuts that might be present.

Doctors often ask me, "Can I use bisacryl inside of BioTemps like that?" I can tell you that, while chemically there is no bond between the bisacryl and the BioTemps material, I have found it to be a procedure that works well.

Even though it doesn't bond to it, the bigger danger with using bisacryl inside BioTemps is that, because it doesn't have a doughy stage like acrylic, you can lock it onto the teeth. As a result, there is no pumping it up and down. Once you put bisacryl on the inside and it goes to its full set, if undercuts are present you can lock it in place; if you have undercuts between teeth, like on the bridges we're prepping here, you can lock it on as well.

That being said, it's important to make sure that you use the acrylic when you have multiple-unit BioTemps situations unless you are absolutely 100 percent sure that there are no undercuts on the teeth or between the preparations themselves. If you are completed assured of that, go ahead and use bisacryl. The acrylic sets up harder; I think it's less porous. And if the BioTemps registrations are going to be in for a while, it's a better idea to use acrylic.

We're now trying in the BioTemps and checking for passive fit on the other side. You want to make sure the margins are down all the way as well. Obviously, we're going to reline it, so if we have a margin or two that was short, it's not going to be the end of the world. But typically, if there's a margin that is short, and you haven't done anything – there you can see how it just rocks into place there, right there that might be the case.

So, the BioTemps go in after we take a bite registration, and the patient will return two weeks later. NEXT APPOINTMENT: We are going to take an impression for both these bridges, and for the minimal-prep veneers on the front. You can see we cemented the bridges with Durelon™, and I use the KaVo SONICflex scaler to remove Durelon from the teeth. The cement flakes right off with a sonic scaler like this.

The patient is anesthetized because this is the impression appointment, and Durelon is just the greatest temporary cement in the world. You'll never lose temporaries, you won't have any sensitivity, the cement is just as snow white when you take off the temps a couple of weeks or even a couple months later because there is just no absorption of bacteria underneath it, no leakage. It's just a great anti-bacterial cement.

But if you don't have a sonic scaler like this the KaVo SONICflex scaler, it is a real burden – in fact, it's almost impossible to get the Durelon off my hands. So, plan ahead: Make sure you have a sonic scaler before you begin to attempt something like that.

Now we're going to go through the steps of the Two-Cord Impression Technique. This is the first cord, the bottom cord, an Ultrapak® (Ultradent) Cord #00 that goes into place first. This sits at the base of the sulcus. And this is the cord that's going to ensure we don't have any bleeding when we pull the top cord out.

So, this cord is not primarily responsible for displacement of the tissue, per se. It does displace the tissue, but its ultimate goal is to ensure we don't have any bleeding when we remove the top cord – the larger Ultrapak Cord #2, which is responsible for most of the retraction here. On no-prep veneers, we don't place any retraction cord. However, on these minimal-prep veneers, where we remove some tooth structure close to the gingival margin, we're going to place retraction cord.

You can see the Cord #00 being put into place and cut short. We want to make sure we tuck the ends, the free ends, of the #00 cord into place, so that we can ensure that we don't pull that out during the impression process. We don't want it embedded in or around the margins, so we want to make sure that the ends of the #00 cord are completely subgingival.

My assistant places the Cord #2, the top cord. Here in California, the dental assistant can place the cord with an extended function license. So, either the assistant or I will put the Ultrapak Cord #2 in, and then place a ROEKO Comprecap on top of that and ask the patient bite down.

We wait eight to 10 minutes before removing the top cord. Once it has been removed, Capture® medium body material is expressed around the abutment teeth in the back and around the minimal-prep veneer teeth in the front. We want to ensure we get that whole facial surface – everything that we've prepped – and then around the bridge abutments and the posterior on the other side.

Then we insert a custom tray into place on the upper for this impression, a palate-less custom tray. And the reason we do that is it reduces gagging, makes it a lot easier for the patient; we use a lot less impression material when we use a custom tray, and the fit of the tray is always perfect.

With a custom tray, it's nice to be assured as you put the tray in the patient's mouth that you are not imposing on any tori, you're not going to run into the tuberosity. A custom tray is always going to fit; it's well worth whatever your lab charges you for it.

Here's a closer look at that upper impression after it's taken out. After about three and a half minutes, we got nice definition around the bridge preparations and the posterior, and nice definition around the minimal-prep veneers and the anterior.

THIRD APPOINTMENT. This is the cementation appointment during which we'll bond the minimal-prep veneers. We're taking off the BioTemps in the posterior – BioTemps really hold up well over the long haul. In fact, there have been many cases where we've taken them on and off several times over a period of six months, when we had some periodontal work done or while we had some hygiene appointments.

I love having my hygienist do hygiene while the preps are done because she can really get in and get everywhere and really make sure that things are nice before we take our final impression. So we clean off the excess Duralon cement with the KaVo SONICflex scaler again.

We try the bridge in and everything fits fine, so we are going to go ahead and cement this bridge.

That cement, if you don't recognize it, is RelyX™ Luting Cement Plus from 3M ESPE. RelyX is just the greatest resin reinforced glass ionomer cement around, at least in my eyes. It's just a fantastic cement, great natural bond strength to the dentin of the tooth, little to no post-operative sensitivity, very easy to clean up, easy to mix – everything about it is great.

Here's the bridge on the other side, going in with that same RelyX Luting cement. I push that into place and clean it up.

That's my assistant cleaning it up; you'll be relieved to know that I do not wear pink gloves as a fashion statement.

Once the cement is completely set, my assistant can clean that up. Then we're going to run some floss threaders underneath those bridges to make sure that we have, in fact, removed all the excess cement.

Once that is done, we will move up to the front and begin bonding the minimal-prep veneers into place. The first step of bonding the minimal-prep veneers into place is to clean up those teeth. We do this with no-preps, too. We do this with really any prep but sometimes dentists think they don't need to do it on a no-prep case because they haven't prepped. However, those teeth always have that solitary plaque, and we just want to get a nice bond to it.

So, we're going to use the pumice. As you see, this is Preppies Whip Mix, the pre-packaged pumice. And then we're using a brush just to make sure that we have all the pumice off the teeth. I find that on these minimal-prep veneers they actually get dirtier than the no-preps because the surfaces of the teeth are kind of rough where we've done some reduction with the diamond itself.

For veneer cases, we always start our try-ins with the translucent shade of the Variolink veneers cement. And the reason we do that is it's the most neutral shade that we have, and it gives us a good idea of whether or not the veneers and the cement are blocking out the underlying tooth colors of it.

Minimal-prep veneers and no-prep veneers are actually shade-adjustable. You can use different shades of try-in cement to give the patient different looks. We, however, always start with the most translucent shade because I think it is the most natural shade of all the different cement shades that we have.

So, the patient looks at it with the mirror – she approves. If she says, "I think it looks too dark" or "I think it looks too white," then we would have gone to a different shade of try-in cement.

Once we've done that – again, using the brush with some water to get the try-in paste off the teeth because it is water-soluble, it likes to hide in between the teeth.

We use floss to make sure we get all that non-setting try-in cement off the teeth.

Now we can go ahead and begin to etch the teeth. When I call these "minimal-prep veneers," to me that implies that all the margins and all the surfaces that we are bonding to are within enamel. So we are going to etch these teeth for 15 seconds.

Rinse that off.

Now it's time to place our bonding agent. And, just like with no-prep veneers, the bonding agent here is an old school bonding agent from a two-bottle system. Instead of using the primer, we are just using the adhesive. And because we have no exposed dentin – that is what we are doing here – we've painted that on.

I use a little air to thin that out, so that we don't have any pools of bonding material anywhere on the tooth. With a typical dentin-bonding agent, we would be using the air to evaporate the acetone.

Here I actually use it to physically thin that layer of the adhesive from the two-bottle system. We do that because it is a little thicker than even a dentin-bonding agent would be.

We're always going to start with tooth #8 & #9, the placement of which will make or break the case. I always put these two on separately, and if I'm ever in a hurry, I still put them on separately. Tooth #8 & #9 are always going to go on first because if these two aren't right, it doesn't matter what the rest of the smile looks like. The esthetics of this case will be off if done incorrectly.

You can see that is the translucent cement. It looks a little yellowish, as you look at the shade of what that cement looks like, but it's not – it's translucent. In fact, if you take the cement and squirt it onto a newspaper, you'll find that this Variolink veneer translucent cement is one of the only cements that is truly translucent. You can see through it!

In fact, that's how I ended up using this cement. We looked at several other brands of translucent cement and they weren't really all that translucent, which is kind of surprising, but they seemed to have picked more of a neutral color than a translucent one. You can see my assistant with the LED light, just going around giving half-second, maybe full-second cures, but usually half-second cures in different areas so I can go around with the explorer and clean the excess cement off.

I know there are clinicians out there who would like to bond the entire veneer in at this point and then use strips to cut through it. I prefer to do a little bonding here, a little bonding there, as you saw in the gingival, clean all that up, then try to get floss in between the teeth.

If that won't go through, I'll take these ribbon saws that you can see here, and go between it. If you've cleaned enough ahead of time, the only thing that you should be getting out of the teeth is bonding agent.

It's really not that difficult to get through unless you've actually bonded veneer cement in between the teeth. In that case, you are going to need to spend some time sawing away through that contact. Again, we're just going to place the next two veneers simultaneously. I begin etching the next two teeth.

You really might be able to place multiple units of crown & bridge because of the fit that they have on the tooth, the mechanical retention as it slides down over the preparation.

So we're going to place those two veneers, and of course, our fixed bridges right behind that. Then we move to the other side to teeth 6 & 7, and then we place those two veneers, going through those same steps: with the pumice, rinse the acid, etch the adhesive, the veneer goes into place with the translucent cement.

We cure that slowly as I clean up the excess cement.

As I did before, I remove excess cement with the explorer, to ensure it is no longer present around the veneer.

Again, I use a ribbon saw to ensure the contacts are broken and that the patient can easily floss.

Then we're using a Brownie. As you can see there, the Brownie is a great way to get cured cement off the facial of a porcelain restoration without scratching that up. I love those Brownies and Greenies for that; the best way to clean up the veneers without doing any damage to the porcelain.

This is a 7408 Carbide bur. We use it to clean up the lingual margin. There's always some excess there, sometimes a little speed bump of cement right where the veneer and the tooth come together. And I love that 7408 to go in there and blend that lingual junction between the veneer and the tooth itself.

Then we're using a pointed bristle brush just to make sure that we've gotten everything out from the embrasures.

You can see some super floss, there's that area that looks like a little soft pipe cleaner or caterpillar. We go through with the floss and taper it through. Super floss just a fantastic job of grabbing the little pieces that regular floss doesn't get.

Our patient's first smile after we've cleaned off the excess cement with the minimal-prep veneers in the anterior and the fixed bridges in the posterior. It's difficult to make restorations in the posterior that look as good as minimal-prep veneers. For this case, we were able to stay completely in enamel in our preparations, which is nice. We have a better bond to the tooth itself, we have less post-operative sensitivity – just all kinds of reasons for doing that.

Here is a picture of the patient smiling. She shows off her improved smile, a very nice end result thanks to minimal-prep veneers in the anterior. This minimal-prep veneer case demonstrates that we don't necessarily have to go in and prepare these teeth for crowns even though we're doing crown & bridge in the back.

We can get a very satisfying esthetic result with the use of minimal-prep veneers, a case that the patient agreed to thanks to the esthetics of the Diagnostic Wax-Up.