Strength
How stress demanding is this case? Think about occlusion, function, and parafunction. This is the first thing I want to know, because it sets the class of material before anything else does.
Christian Coachman Digital Smile Design
There is no best material. There is only the right material for the case in front of you.
Three things can rule a material out: how much strength the case demands, how far you are moving the shade, and how thick the restoration will be. On your case, one of them is binding. That is the one worth knowing before you prep.
Six questions · About 60 seconds · Monolithic restorations
It is free, and you get the whole answer before I ask you for anything.
Nine restoration types
Everything here is about monolithic restorations. That is how we solve almost every case now, and it is what this tool is built for.
- Inlay or onlay
- Veneer
- Anterior crown
- Posterior crown
- Implant crown
- Anterior bridge
- Posterior bridge
- Full arch implant bridge, monolithic
- Full arch implant bridge, hybrid with a bar
How the decision works
Which one is actually deciding your case?
Three things can rule a material out. On your case one of them is the binding constraint, and the other two are just along for the ride. Here is what I ask about each, and why I ask in that order.
Color
How far are you moving the shade? This matters more than most dentists expect, because the bigger the change, the more you need to block what is underneath, and blocking means opacity or depth. Both of those have consequences.
Thickness
The lithium materials are safe between 0.5mm and 0.8mm and gray out above it. That thickness rule applies to the lithium materials only.
Of the three, color is the one we actually measure. So it is the one I can show you the numbers for.
How we measure this at the lab
| Shade change | Example | Buccal depth |
|---|---|---|
| 1 shade | A1 to BL4 | 0.3mm |
| 2 shades | A2 to BL4 | 0.5mm |
| 3 shades | A3 to BL4 | 0.7mm |
| 4 shades | A4 to BL4 | 1mm |
| Super dark and/or opaque | Gray, brown, black, or metal substrate | Over 1.5mm |
The more opaque the material, the more you can block the color with a thinner depth.
Or read one all the way through first. Here is a case where the third factor is the one that decided it.
A worked case
One case, from the first question to the protocol
Every line below is what the tool returns for these six answers. Yours will be different.
The case
Veneer · Medium strength · 1 shade · Over 0.8mm
What I asked
-
01
Answer: Veneer
What are you restoring? Classify the case into one category. This is how we organize every material decision at the lab, and it is the reason the decision is manageable at all.
-
02
Answer: Medium
How stress demanding is this case? Think about occlusion, function, and parafunction. This is the first thing I want to know, because it sets the class of material before anything else does.
-
03
Answer: 1 shade
How far are you moving the shade? This matters more than most dentists expect, because the bigger the change, the more you need to block what is underneath, and blocking means opacity or depth. Both of those have consequences.
-
04
Answer: Over 0.8mm
Roughly how thick will the restoration be?
-
05
Answer: No
Is this part of a combination case? Veneers plus crowns, implant crowns, or bridges in the same case.
-
06
Answer: No
Do you trust bonding to zirconia? Be honest here. This one question changes what I would recommend to you, and there is no wrong answer.
What came back
My recommendation
Feldspathic or Translucent zirconia
Over 0.8mm, lithium disilicate is out. Past that thickness it drops the value and goes grayish on you, and it does not matter which brand you use. That leaves feldspathic, if the strength demand allows, or translucent zirconia if it does not.
What decided it
Thickness decided this one. Over 0.8mm the medium-strength class drops its value, and that rules it out here.
StrengthNot the decider
ColorNot the decider
ThicknessDecided it
On the line
Your case sits on one of the lines where the answer could go either way. Tell us when you order and we will talk it through.
Alternatives considered
Empress
Favorable
Medium strength class, top esthetics on the matrix.
Vita Enamic
Favorable
Medium strength class.
Lithium disilicate
Favorable
In its 0.5mm to 0.8mm window.
The interface argument
Most dentists worry about the wrong interface. There are three components in a bonded restoration: the tooth, the cement, and the restoration. That means two interfaces. Following the APC protocol, air abrasion, a primer with MDP, then resin cement, the bond strength between cement and zirconia is almost the same as between cement and lithium silicate. And both of them are much stronger than the bond between cement and dentine. The weak link is always cement and dentine. It is never the zirconia.
If you do not trust the bond
You told me you do not trust bonding to zirconia. I still think zirconia is right for this case, so here is the option: we can bake a micro-layer of ceramic inside the restoration at the lab. Your bonding interface becomes lithium disilicate, and you treat it chairside exactly as you would treat a lithium disilicate restoration. Marcus Blatz’s position is that this extra step and extra interface make no sense, and the evidence is with him. But if it is what makes you comfortable, we can do it, and you should ask us for it when you order the case.
Chairside conditioning protocol
Feldspathic
Sandblast
No sandblast
Etch
9.8% HF acid, 2 minutes
Bond
Silane
Translucent zirconia
Sandblast
Sandblast 27/50 micras, 2 bar, 5 seconds
Etch
No etch
Bond
Primer with MDP
Christian’s note We do not condition restorations in the lab, and that is deliberate. You need to try it in, adjust it internally if you need to, then clean and condition it yourself right before you bond. If we conditioned it here and you adjusted it there, the conditioning is gone and nobody knows who owns the bond. This way you own it, and you own it at the right moment.
Worth knowing
One thing worth knowing before you commit. Zirconia is at least 50% harder to cut out than lithium disilicate, which is already hard. If there is a real chance this restoration will need to come off one day, weigh that now rather than later.
That is the whole answer, for one case.
Where this comes from
The decision logic in this tool is not a formula. It is how our restorative team actually reasons through a case, written down.
Angelo Raphael, our Clinical Director of Restorative Dentistry at the DSD Planning Center and DSD Lab, built the materials matrix it draws on. He and I spent two long recorded sessions arguing through the logic before any of it was written, and this tool is the result of that argument, not a summary of a brochure.
Where it stops
This is a good starting point. It is not the last word.
Some cases sit on a line where the answer could genuinely go either way, and when yours does, the tool will tell you rather than pretend. That is not a hedge. It is the difference between a tool that respects the decision and a lookup table that flattens it.
If your case is one of those, talk to us when you order it. And if you disagree with what comes back, tell me. I am open to a different point of view, and that is how the matrix gets better.
— Christian Coachman
Ask Christian
Now tell me about yours.
Same as I would tell you if you called the lab.
Six questions · About 60 seconds · Monolithic restorations