Porcelain survey

[toe]

What porcelain do you most commonly use.

[JEmirzian]

As a new lab, my wife and I wanted a universal porcelain that would be more versatile for our small lab. The Avante system from Pentron is what we choose. So far it has worked well for us.

Jay

[Travis]

I have been using Ivoclars d.sign for 6 years now. I hope I find more people who use d.sign so I could get some advice on using it.

[Craig]

We use Ivoclar's InLine porcelain. I've found that the esthetics are about equal to dsign, but the handling characteristics are much better. I did like dsign quite a bit, but there were times when I needed to have a more predictable result on the first bake. But dsign is an organically based porcelain, so as it dries, it forms a skin, then when the vac pulls, it can actually pull the air and water through the skin, causing steam tears. We eventually figured a way around that, but it wasn't 100% predictable.

Craig

[Travis]

Did you do your anatomy in your buildup on posteriors using d.sign? I have always had a hard time with the pulling and tearing.

[Craig]

Yes I did the anatomy in the buildup. The best trick I discovered at preventing the tearing, was to get rid of the dry time. Send that crown up wet, and as fast as possible. Thereby preventing too much of a skin to form and allowing the moisture to pull out without tearing.

I hope that helps.

Craig

[Tony Atkins]

I have found that all ceramics can suffer with steam tearing, This can be caused by various factors if I list them it may help diagnose some of the possible causes,
1: The temperature with which you place your ceramic build up into the furnace, be careful as the glass point of many ceramics is actually quite low some are as low 575degrees c, As mentioned before if a build up is placed into a furnace to close to this temperature the surface crystalisis and prevents the moisture from escapeing, Hence we get steam tearing, this effect is exagerated with larger bulid ups or where there is greater mass of porcelain. Allowing the temperature to drop to it's preset temperature after the previous firing will help this, generally I place all my ceramics in at 450degrees c and since have not experienced steam tearing.
2: When you have a combination of large masses of alloy and thin areas of ceramic this tends to occurr most in the interstitial areas of bridge work, Others would generaly say that shrinkage occurs in the areas of least resistance ie thin section of ceramic large mass of alloy. Another instance where tearing of the ceramic can occur is when there is equally a large mass of alloy and a large mass of ceramic especially where implant supported crowns are concerned there are generally two ways of eradicating exsesive shrinkgae in these two cases.
1: in the instance of bridge work I make sure I completley seperate through to the opaque before fireing, therfore allowing the porcelain to shrink evenely and ultimatley avoid tearing trying to fill in tears without opening it up first is nearly always impossible, then on my second addition I mix low fusing correction 50:50 with a half shade darker dentine to maintaine colour this will allow the ceramic to melt more easily into the proximal areas.
In the case of implant supported crowns it doesnt appear to be so straight forward, Basically what we have to do during the fireing process is to allow the alloy and ceramic to expand and contract at the same rate this is due to the fact that metal is a very good conductor of heat and ceramic isnt, therfore the alloy expands before the ceramic does so we must lower the rate of climb 55 degrees c per minute being the optimum for a ceramic. My starting point would be say 45 but when lowering the rate of climb it may be an idea to lower the final temp by the same number of degrees with which you lowered the heat rate, then allow the restoration to slow cool to 7oo degrees before removing from the furnace keep an eye out for devitrification of the porcelain as lucite will grow within the ceramic more readily when slow cooling which can result in a very glassy looking ceramic I hope this has helped
best wishes.
Tony

[TheLabGuy]

Very interesting stuff on d.sign,
Steam Tears = lower the intial heat temp. (Tony) OR get rid of the dry time (Brian)
Bridges= always seperate (Tony)

Currently, I use Finesse (Dentsply, getting rid of it within two weeks), D.Sign (Ivoclar), Avante (Pentron), E.max (Ivoclar), Esthetic (Ivoclar). I wanna try the Noritake system because of the price, so hopefully in the future I will.

My favorite is D.Sign, because I'm a color whore, you throw that on a Captek crown you won't find better chroma, hue, and value. It can be a *bleep* to work with sometimes, but hopefully some of the tricks above will help out with some of the tearing.

[sixonice]

A couple helpful tips with d.SIGN I have learned: Like the other members said, initial entry temp is crucial. Too high of a temp bakes the surface of the restoration and forms a dry "crust" trapping any remaining moisture inside as the furnace closes. This results in the remaining moisture to "boil" it's way out, usually blowing through the occlusion or margin area. Just be sure the initial entry temp is 400C - no big deal. Also, try sprinkling/dusting some margin porcelain on the still WET 2nd opaque, then tap the excess off. I use a dry brush, just dip the tip in margin porcelain (I use A1 on any shade becuase it is such a small amount it does dot effect anything) and tap it on the wet opaque. This works wonders in creating a bit of mechanical retention to eliminate pulling. It also gives the crown a nicer look, allowing the light that enters to "bounce" around internally. This step takes 1 extra minute, is easy and works.

[TheLabGuy]

Great idea Sixonice, I would of never thought of that, kinda like using crystals in your opaque, but using margin powder instead......very interesting.

[sixonice]

Originally Posted by TheLabGuy

Great idea Sixonice, I would of never thought of that, kinda like using crystals in your opaque, but using margin powder instead......very interesting.

Exactly!! The margin works best because it fires very close to the opaques. After it comes down from the 2nd opaque bake with the margin sprinkled on it, you will have a nice (almost like super fine sandpaper) finish that will help eliminate any pulling. This will save you at least one more bake!