CEREC Doctors

Blog Author: Mike Skramstad


I have had mixed feelings about the Katana (especially vs e.max cad) since using it.  On one hand, the Katana STML looks and fits fantastic.  On the other hand, you can expect it to take a good 20-25 min longer than a typical e.max (if glazed) and a little less if polished.  I have gone back and forth if the time is worth it.  After using it for awhile, I found myself starting to go back to e.max CAD due to the time.  After a little more thought and clinical results, I have decided that in a lot of cases, it's worth the extra time.  The stuff just looks and fits fantastic...AND there is better detail.

That being said, the other question is should you glaze or polish.  I have done both and they both work out nicely, but I have realized that you have to be a bit careful about shade when deciding how you want to finish it.

As a general rule of thumb... polishing zirconia tends to produce a pearl effect, but it ALSO will lower the value.  For that reason, I would tend to choose a shade that matches the shade you are trying to achieve (when polishing). As you can see in the slide below, the company recommends one shade brighter when polishing due to the decrease in value... but that might be overkill. 

If you are glazing, It will increase the value and make it brighter.  In that case, I would choose a shade one to maybe even two shades darker than your target shade.

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Here is a case that illlustrates that.  Both were done in A3 Katana STML.  Tooth #13 was polished and tooth #14 was glazed.  Both were clinically great... but notice the lower value of tooth #13 that was polished.

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I hope this helps

24 Jan 2018

Posted by Mike Skramstad on January 24th, 2018 at 12:57 pm
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I haven't posted a case in awhile... thought I would post one that I just finished...

Preop situation: Patient had very old veneers on front 6 teeth.  He wanted to change them out with a "whiter" solution and also wanted a fuller smile.

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We decided to do the front 8 teeth to take care of his buccal corridor issue.  We imaged with Ortho software and sent to lab to have a digital waxup done

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After rough prepping the teeth, we transferred the waxup to the mouth and then did final depth reduction

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Here are the final preparations:

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And here is the final result.  Vita Mk II 1M1

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I thought it would be a good exercise to go through an entire implant process documenting a failure of a healthy bicuspid.  I also will include a couple tricks at the end on how I dealt with a small issue.

Healthy tooth #4 as taking on standard intraoral photographs and radiograph on routine cleaning appointment

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One year later, she came in with significant symptoms on the tooth and it was very evident what had occurred:

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We treatment planned an extraction and site preservation graft and allowed it to heal for 5 months time.  After healing the site was ready for implant planning and placement:

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After 3 months of integration we started the restorative process.  We scanned with a tibase instead of a scanpost in this particular case and took an xray to verify the seating:

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We made a decision to use a multilayer technique on this case instead of screw retained (which would have been possible) because I prefer the ease of delivery of cement retained implant restorations, but I also like having more material options.  In this case once we split the restoration and had proper thickness of the veneering structure... there was a problem of the tibase sticking through the abutment.

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I left the design as is and milled the abutment out of zirconia and the crown out of e.max HT using EF milling on the 4 motor milling unit:

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Once the zirconia abutment was seated, you can see that the parts fit together perfectly

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However, when bonding the tibase to the zirconia abutment... the tibase was infact poking through the zirconia abutment just like the design showed and this obviously prevented the parts from seating properly

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To correct the issue, you can simply use the abutment as a reduction coping and "flush" the tibase that is sticking through to the zirconia abutment.  This should not affect the final restoration if it's just a little bit like in this clinical case

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Once complete, everything was delivered in the mouth.  Besides the shade being a bit light, the overall process was a success. 

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I hope this process helps some of you in the tighter interocclusal spaces where you would like to use the multilayer design mode.

 

11 Oct 2017

Posted by Mike Skramstad on October 11th, 2017 at 01:04 pm
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Those of you that were at my lecture in Vegas at DSW 2017 saw me do some bigger cases digitally.  I thought I would post a case that I just finished that shows this workflow

​I have seen this patient for some time and she has always told me that she does not like her teeth.  She is mostly unhappy with 3 things:

  • The lines and discolorations in her teeth
  • The shape of her teeth (specifically #7)
  • Tooth #9 was more facial than tooth #8
  • The open incisal embrasures between the canines and the laterals
  • The minor collapse of the buccal corridor
  • The unesthetic crowns on #3 and #14 (recession and margins that showed)

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To give you an idea what she was seeing, here is her smile:

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I knew that we didn't need to change a lot...She had a very normal tooth display at lip at rest for a 46 year old woman:

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I think it's important to REALLY talk to the patient about what they want so you are clear when designing the case.  She made several requests including the following:

  • She wanted her concerns fixed, but didn't want people to know that she had fake teeth.  This meant a very natural shape that almost mimicked what she had now... just chaning the shape and buccal corridor a little bit
  • She didn't like the "blue" at the edges... which means I have to watch the incisal effects
  • She wanted a natural shade... nothing bright.  More natural

So I took this information and scanned her with the Ortho software.  I exported the scan to my lab technicial Bill Marais and he digitally designed the smile via Exocad.  Now often times I will have him send me the case via .stl and I will 3D print the case and use as Biocopy.  In this case we did more of a "hybrid" approach in which he "milled" the digital waxup on a 5 axis mill with a grey "puck" and then used his hand skills to define certain areas.  We did this because I wanted details and it's difficult to get this kind of detail via 3D printing.

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Next we duplicated in white stone just in case... I use this to make a Copyplast matrix for a reduction guide, to transfer the waxup to the mouth for depth reductions, and also to fabricate provisionals.

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We went ahead and prepped the teeth.  We made the decision based on the waxup to prepare more of a full coverage veneer type prep.  We tried to keep everything in enamel as best we could due to this prep style.  We prepped a little more based on the decision to move the teeth slightly lingual in the anterior.  This also helped us control the function:

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Tissue control is very important.  I don't like dealing with inflammed gingiva so one tip is to make sure you pack cord prior to defining the margins so you protect the gingiva:

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IMO, it's very important to get the waxup model to stitch with the prepped teeth.  This makes a MAJOR difference in how easy the design is and how much closer it will replicate what you are trying to execute.  For this reason, we left the molars intact (no waxup on these teeth either) and use them as stitching abutments to correctly overlay the waxup to the preps:

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By doing that, here are our designs.. initial proposals took very very minor tweaking (only about 5 minutes)

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I went ahead and exported the .stl of the preps and 3D printed a prep model.  It was a solid model so I manually ditched the margins with a bur to get the restorations to seat.  Here are the e.max restorations milled in EF mill (Extra Fine for better trueness):

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I did some small incisal effects with Ivoclar Ivocolor and then polished the restorations (no glaze).  Here they are ready for delivery:

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And here are the final restorations bonded into place with Variolink Esthetic warm.  She was very happy with the result.  I think I could have maybe done a little more contouring (some washed out in the picture)... but shape is always the most important thing and we did what she asked... creating more of a monolithic tooth with a natural shape and natural color:

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11 Sep 2017

Posted by Mike Skramstad on September 11th, 2017 at 03:01 pm
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I have done very few bridges in the last few year...but sometimes you have to.  This patient came to me with a ton of pain on a tooth that he said was extracted 8 years ago.  After I took the PA we noticed the problem... an infected root tip that was left.  He has been wearing a flipper.

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He initially wanted to do an implant, but after flapping and extracting the infected root, we realized that extensive bone grafting was going to be necessary and it just wasn't in his budget.... so we did a bridge today (about 8 weeks after extraction).  The bridge was e.max A3.

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He was quite happy.  This is immediate post op today...  An implant would have been nice, but some scenarios a bridge does the job.

11 Sep 2017

Posted by Mike Skramstad on September 11th, 2017 at 12:09 pm
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Prepping a full upper arch next week and just wanted to post this amazing waxup I got from Bill.... He always amazes me.  It is expensive at $85/unit... but totally worth it!

Preop:

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Bill digitally waxes up in Exocad and prints it in an Acrylic puck... then after mill does hand touching and adjustments:

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He then duplicates in white stone in case you would like to show to patient

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Includes a great stent to transfer to the mouth if needed or for provisionals.... and a prep guide:

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07 Aug 2017

Posted by Mike Skramstad on August 7th, 2017 at 11:52 am
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Here is a case I did on my wife's cousin.  She had a trauma a few years ago that resulted in the tooth darkening quite a bit.  We did the endo and tried internally bleaching twice and it was not successful.  We decided to do a single unit veneer to correct both the dark color and the minor rotation.

The case was done in Biogeneric and the material was Vita Mk II 1M1 with stain and glaze. 

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18 Jul 2017

Posted by Mike Skramstad on July 18th, 2017 at 08:33 pm
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Was just going through tons of pictures tonight and this is a case I finished a couple weeks ago.  I don't do many bridges, but you have have to love the workflow when you do them.

  • Prep Abutment teeth
  • Image preps and root
  • Mill Teliocad Temp and extract root while milling
  • Reline pontic to form ovate pontic and cement
  • After 10 week healing time restore...

Works beautifully...  Also, if you have the 4 motor mill, use EF milling.  Takes  a long time, but the mills are phenomenal.

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20 Jun 2017

I just wanted to show a case that just got seated today.  It was a bridge from 2=5.  I would have preferred implants obviously, but the patient did not want to do the required grafting, etc... to do it.  She was rather concerned about esthetics... so what do we do?  I don't use e.max bridges in the posterior anymore and the high strength zirconia would have not looked good enough.  I could have sent to the lab for a layered bridge... but I tried to use translucent zirconia instead.  I have talked extensively about the short comings of this material.  Even though the flexural strength of this material I used is 600mpa, there is no transfomational toughening present so it is much weaker than the zirconia that we all use same day.   This is Copran Ultra Translucent zirconia from Empire Dental Solutions. 

The result was excellent... will it work long term?  We will see.  The connectors were about 14mm2 on this and it was cemented.  I fired it for 9 hours in the S1 furnace (cannot use Speedfire for this).

Just thought I would post as an option.

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I saw a comment on the boards the other day that asked this question.  It was funny because I am going through a case right now that I had some issues with this.

I don't exactly know how to answer the question to be honest.  There are many different things i've heard.... things like the blanching goes away in 20 min or less,etc...  The way that I have done it in the past was just by "feel".  That is... I want to put pressure on the tissue and I can usually feel if it's too much by how it seats.  If I have trouble, then I will adjust.  It also will depend on anterior vs posterior and how much tissue I need to move.

Here is a case replacing 2 congenitally missing lateral incisors.  He has been wearing a flipper for over 10 years and finally wanted some teeth.  Here is the initial preop photo...

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After doing the plan, we placed the implants guided in the site

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I let heal about 3 months.  Since he had a flipper, I just used healing caps that were flush with the tissue and adjusted his flipper for the provisional.

Here is how the tissue looked at full healing:

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As you can see, I have a lot of tissue to move, especially on tooth #10.  Now, here is the mistake that I made.  I tried to move it too quickly.  Meaning, I pushed on the tissue way way too hard.  It was difficult and painful for the patient (I did not numb up).  #7 was still painful, but not that bad because I didn't have to go as far...

Here are the initial provisionals:

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How do I know I pushed too much too fast?  Here is an iphone picture my assistant sent me two days later (it's her brother in law)

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Yikes.... I had to have the patient in immediately, get the provisional out, recontour it quite a bit and put it back in.  That with a chlorohexidine rinse healed the problem in about 4 days.... Here he is as of Monday:

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So.. be careful.  If you need to move the tissue a lot, do it in a couple stages and not all at once.  You may get lucky and it will work... or you may end up having a significant issue like I did on this case.