Blog Author: Daniel Wilson
It's been a while since I've posted anything. Long summer and trying to get back at it. I think for all of us on here, we are thankful for technology and the constant evolution of materials and digital dentistry.
This case I'm sharing is something that all of us see each day. How I approach this today is different than I would have approached this pre SpeedFire and pre-Katana. I simply love the fit of Zirconia and the anatomy right out of the mill. I can be much more conservative with my margin preprations and edge stability of Zirconia during milling is wonderful. The other reason I do a lot of chairside zirconia and Katana is that I love the ability to cement on those deep margins or those patients where it is really difficult to isolate and bond well. (I will say that Kuraray-Noritake does not advocate cementing Katana STML with RMGI) To make myself feel better on these cases where I am not bonding Katana, I am making sure my fissure height on my design is 1.20mm or greater.
So here is a case that I just did. Tooth #30 had gold onlay that came off.
I tend to choose a shade that is one shade darker than I am shooting for. In this case, I wanted to match the shade of the occlusal 1/2 of tooth #29. I felt like that was A1 so I choose A2 Katana STML.
Deep recurrent decay that I removed and built back up to ideal.
It does take extra time but I do think there is significant improvement in esthetics with a Katana crown that has been glazed versus polish only. In this case, I pre-polish my crowns before I sinter them. Post sinter, I lightly air abrade the crown to take away the surface tension so the glaze will adhere uniformly. In this case, I choose to use Empress Stain and Glaze and fire on P4.
I schedule all of my crowns for 2 hours so this isn't really a huge deal for me to spend the extra time for a glaze fire. I tell the patients it will be about a 45 minute wait. During this time I am doing another procedure. I haven't received a complaint from a patient. But our team does prep all patients before they schedule to expect to be at the office for 2 hours.
Overall I'm quite happy with the final results and esthetics. I know there are some that don't have a SpeedFire and doing Katana is not possible, but for those of you that do, I think Katana is a wonderful material and I am using it more and more.
Inventory. It's a love hate for me. I love to try out new materials and have lots of material choices and have all the shades under the sun.
But as a business owner who is trying to run a successful, profitable practice and set the tone for our doctors, I need to be smart.
When I first started using CEREC, I saw post after post from doctors warning us against using IPS e.max HT. If you do, you will get the dreaded "grey" crown. As many of you have seen, I do a lot of HT in the anterior, for crownlays, and if I'm trying to match a patient with a C-shade. In my eyes, C shades are just a lower value of A shades. Sometimes we just say the tooth is "grey" but on the flip side, we can use this to our advantage. If I see a lower value, C-tones or "greyness" in a tooth, my thought isn't to pick a C-shade, it is simply to use IPS e.max HT.
Here's my rationale. It keeps my inventory simple. As I already stated above, I have a lot of uses for the HT block. One of the other qualities of an HT block is that the value can be dramatically affected by the color of your cement. For a case like this, I can use this to my advantage by understanding the nature of qualities of my block on hand. People have argued that I should just pick a C2 or C3 LT block and that is just easier. I look at it from the other end of the spectrum in that using the HT block kind of bails me out if I don't choose the exact right shade. Let's look at this case.
I put the A3.5 shade tab up just to show the lower value of the teeth compared to the tab
This is a case that I see C-shades and automatically think about HT. I told my assistant that we would be doing A3 HT and that she would be doing the rest. I'm really been trying to train up my team members and not do all my stain and glazing.
Below are the Pre-Op, Try-In and Delivered Crown. All we had was A2 HT left, so this made my assistants job a little more challenging with staining down this crown to get it to match. I told her to use a little of the e.max "1" stain for the gingival 1/2, some of the I-2 stain for the cusp tips to drop the value down a little more and to add some white to create some craze lines. Overall, she did a good job with the staining. At Try-In, the value was too bright for my tastes though I wasn't trying to match the "darker" canine, I still wanted to lower the value down more. If I had done the C2 or C3 LT block, the different color resin cements wouldn't make too much of a difference. In fact, the thicker your porcelain, the less of a difference the colored cements make. As you can see from the photos, the occlusal of the tooth is relatively unaffected from the Warm + cement.
There isn't anything too incredibly special about this case, but wanted to share some things I've learned about IPS e.max HT and how I use it. I hope this can help others not be intimidated by the block and utilize it when appropriate.
Fortunately our chairside options for bridge blocks is growing. With Ivoclar Vivadent coming out with some blocks, 3M and Katana Noritake will be releasing there STML bridge block later too. Originally I used to push the limits with IPS e.max bridges with the B32 block. I had one failure with connectors that were adequate 18mm2 but they were short. Now I tend to only do IPS e.max bridges if I am doing an anterior case or a premolar pontic.
So here is a case that I just did with CEREC Zirconia A3 in the medi S block. The challenge with CEREC Zirconia in my opinion is the opaqueness and the high value. For me, I'm always trying to tone that brightness down and give the restoration more depth of color. What has worked well for me is infiltration stains from VITA and then stain and glaze to follow. Here is a lower posterior bridge that I just delivered. After design in the software, I used my infiltration stains and then did 45 minutes drying and sintering cycle.
I bought the Zig Detailer Brushes on Amazon for like $5/each.
After the sintering cycle, I fired the case on P4 with Empress Stain and Glaze. I used a bit of Mahogany in the grooves and for the embrasures. A little bit of A shade stain for the gingival aspect. Added very little Incisal 1 (Blue) for the translucency for the cusp tips. And then white to create accents and highlight the other colors.
Overall this case isn't perfect, but I think it is a good option for us chairside. As an aside, I did this case in two appointments. Milled the provisional bridge with 2M2 Vita CAD Temp.
Something that I've picked up through the years from Sam, Flem, Skramy and my wife, Kris, is that natural teeth have a lot of white in them. When used well, I've found that it can make teeth really look a lot more natural and will give a monolithic restoration a lot more depth. I use white to add decalcifications, mimick craze lines, enhance translucency and oftentimes, it is just what the case needs. I will say this takes a little practice and it is easy to not have enough or too much. For a few of the cases that I will show, I really think it adds a little extra and makes the restorations blend in better. For many of you that see my posts, I often will use the Empress Stain and Glaze Kit on my cases because of it's ease of use. (For IPS e.max, make sure you have the restoration crystallized first if you are going to use Empress Stain and Glaze).
1st Case: VITABLOCS TriLuxe 1M2-A little sunset color stain gingivally but the rest is subtle white striations
2nd Case: Empress Multi B1 #9-This is an off angle pic but really showcases using white enhance the restoration
3rd Case: The before is the classic monolithic crown without anything. I used VITABLOCS Mark II 1M1 and just added glaze and some white to attempt to match the white spots
I'm sure many feel like anteriors can be a labor of love, especially handling single centrals. I never feel like I charge enough for some of these cases. Here's a case I completed today. This was a college student who was heading back to school on Sunday and his family wanted me to complete his case before he headed back. He had some trauma to #9 about 7 years ago and had it repaired by his pediatric dentist. He also plays the clarinet competitively as well and the asymmetry between #8 and 9 was causing him some frustrations with his mouthpiece. Because of his scholarship for music, he had zero interest in orthodontics.
So when I see cases like this, I'm trying to plan the case before I touch the tooth with a bur. Mike, Sam and Flem really do a great job of getting you to develop a gameplan before you tackle these cases in Level 4. Prep design, Facial reduction, core color, occlusion, block selection, characterization, etc...
As you can see, the VITA Classic Shade of A1 is close in color to the adjacent tooth #8. I choose IPS Empress CAD Multi for this case and even though Empress to me tends to be a little brighter, I chose a B1 Multi block for this case. I know that with less facial reduction and the goal of trying to preserve enamel, I will get a value drop on these cases. Your facial thickness of porcelain is critical to take into account on all of these cases. If you ignore it, you can get burned quickly, ask me how I know.
The preps look aggressive but the facial reduction is minimal 0.5-0.7mm. I almost always break contacts and I try to have smooth, rounded margins to help allow the restorations to drop into place and have a great fit with CEREC. This case was stained and glazed with Empress Stain and Glazes and fired on P4. I missed the texture a little on this case and width could have been better as well. Overall, I would call the case a success with a happy young man and family before he heads off to college.
I received a sample of Ivoclar Vivadent's Tetric CAD. This was a case that I thought would be more of an onlay and my mind was dead set on using the block. In my humble opinion this block is perfect for inlays and onlays. The tooth's condition dedicated my prep and with the presence of distal decay that wasn't apparent on the radiograph and with the small buccal breakdown, I changed gears and went with a crownlay prep. In the past, I would typically use IPS e.max HT or MT for these crownlay indications.
Tetric CAD is in the category of hybrid ceramics. It has great edge stability during milling, polishes easily and doesn't have to be fired. With a flexural strength of 272 MPa, it is higher than the other hybrids. I bonded this restoration with Ivoclar Vivadent's Variolink Esthetic DC Warm cement under rubber dam isolation. I have attached a CEREC Materials spreadsheet that I posted earlier this month for those that would like to see the different materials and their properties and indications.
This appointment was less than an hour from start to finish. Polished only. Despite the fact that the value is a bit high occlusally, it still blends beautifully around the margins.
I know there is a lot of discussion about what materials to use in the anterior zone. I don't think there is necessarily a universal answer but what I've learned over the years is to understand the properties of these materials and their strengths and weaknesses.
In general, I'm trying to use Feldspathic porcelain (VITABLOCS typically for me Mark II or TriLuxe) or Leucite Re-inforced Glass Ceramics (IPS Empress) in the anterior region. I feel like they have more vitality, given the right case, you can just mill polish and cement and get a really nice result. This is a case with VITA TriLuxe 1M2 polish only
I know the go-to block when using e.max in the anterior region is e.max MT. I really like the block and use it quite often as well. My point for this discussion is that a lot of doctors will shy away from e.max HT. There is the big fear of the dreaded "grey" crown or a crown that has "low" value. It is a real concern. I've had it happen to me and if you aren't careful, it can happen quite easily. This was my first case I posted on CEREC doctors and at the time I thought it was quite good. Now I would have approached it differently because of the "low" value of #8,9.
This case I did about a year ago. It's not perfect but it is a vast improvement over what she started with. She is quite happy, but I always evaluate my photos and have other CEREC doctors look at them and give me their feedback. Dr. Tom Monahan and I share cases back and forth, and aren't afraid to pick apart our cases. It makes us better and I would encourage you to do the same.
So I chose HT for this case because I felt like I did see some C-tones in this case. I felt like MT would be too bright or high in value for this and I didn't feel great about using Feldspathic on this case because of limited space on the lingual. So I used A1 HT. I compensated about 2 shades in order to offset the drop in value. I wish I would have taken a pre-op pic with a shade tab but she was closer to A3.
There are a lot of ways to approach these anterior cases, but I felt like e.max HT was the best solution and what I saw for the case in my eyes.
This was a patient who arrived at my office after a less than optimum orthodontic finish and failed hard and soft tissue grafts for the area of #8. I encouraged her to see my periodontist that I work with, but she was "tired and done". She couldn't stand her essix and wanted a bridge. I talked her out of it and said that we could do something as a long term temporary and then when she was ready, we could explore grafting and implants in the future. I bonded #7 to correct the mesial concavity. #9 was used as the retainer. I did prep slightly on the lingual of #9, but still kept the prep in enamel to maximize the bond for the restoration.
This was a 2 hour case. I stained and glazed in the mouth but still needed to do a second fire to get it to my satisfaction. I used IPS e.max A1 LT.
This isn't a novel post but for some of the new CEREC users, I thought I would share some bread and butter dentistry. I would rarely do crownlays during the BC (Before CEREC) days. As we all know the biggest challenge was provisionalization and you as the clinician had to be knowledgeable enough about materials to explain to the lab technician about material selection, color and translucency so you could get the results you desired.
Now with CEREC, there are a number of different materials at our disposal and no worries about provisionals. For this case, I had plenty of enamel to bond to and enough clearance so I could have used just about anything in this case. Typically my go-to for crownlays is IPS e.max HT (high translucency). I've used MT with success but I find blending the margins is a bit easier with HT.
Another thing I really try to focus on with these cases is smooth flowing margins. Unlike the days of gold inlays and onlays where sharp internal line angles and boxes were the norm, resistance and retention form are not my primary concern. With proper bonding, these do not come off.
For this case, I intentionally choose A2 HT because the cusp tips of the premolars where brighter. I selectively etched the enamel with 35% phosphoric acid, scrubbed the tooth with Adhese Universal for 20 seconds and bonded with Ivoclar Vivadent Variolink Esthetic Warm Plus.
Nothing earth shattering, but these are the types of cases where efficiency and predicatability are paramount for us each day.
CEREC gives us a ton of options and allows us to do treatment for patients without the frustration to us as clinicians or frustration to our patients. For me one of those treatments is Maryland Bridges. As we all know, if we attempt to do this with a lab, provisionalization is challenging and we are at the mercy of the lab for getting the shade and fit correct. CADCAM has made this a very efficient and predictable option for us chairside.
This patient has a lot of compromises but really wanted something fixed versus her removable partial to replace #23. As you can see from the radiograph, tooth #24 is not doing well. I had her get a consultation from an endodontist and took a CBCT. He thinks it looks fine and would be a candidate for an abutment but I still think the tooth is toast. I really wanted to avoid potentially opening a bag of worms with #24 and didn't want to prep #22 for full coverage to act as an abutment for a conventional 3 unit FPD.
So after some discussion, I felt a Maryland bridge was the best option. In this case, I did prep a little into the canine a little bit.
Here's the proposal:
Restoration at try-in:
I used a C14 block A2 LT. I did have to re-fire this case a second time for color.
Nothing earth shattering for this case, but I'm still amazed how we can do this in less than a two hour appointment and be ultra conservative and get a great result. I don't know how long this will last (I've been searching on PubMed for articles that Skramy refers to but couldn't find them), but with total etch and enamel bond, I think it will do well for quite some time.