Zirconia Maryland Bridges

[PDC]

I am in the process of remaking a couple of Maryland Bridges (which I have never liked doing). I told the doc that there is a good chance of the abutment teeth graying out when the wings are place...so that's what happened. Now I am in the process of doing zirconia Maryland bridges, but the first ones did not fit at all. Has anyone on this forum had any success with fits on these things?

 

[paulg100]

yeah done a fair few. Work fine as long as you put a spacer in the wing with a small border and put a ceramic slurry inside, so that it will etch.

The other way im being told about at the minute is apply a bonder to the wing, like ivoclar's monobond plus. This saves the slurry work aroud..apparantly. Need to look at these bonders more closely first before id say if this works or not.

If you dont do this i can promise they will keep falling out..ask me how i know

When you did the metal marylands did you only take the wings half way up the back of the tooth?

 

[DMC]

They are good.

Done many. When occlusion is tight, could be a prob. no matter what you make it out of.

 

[PDC]

When you did the metal marylands did you only take the wings half way up the back of the tooth?[/QUOTE]

The doc had prepped the linguals to cover most of the entire surface...maybe except a mm or so from the incisal edge. The patient had fairly translucent teeth which further exacerbated the problem.

In regards to the porcelain slurry, have you just tried glazing the undersides of the wings and etching that?

 

[Bobby Orr ceramics]

When you did the metal marylands did you only take the wings half way up the back of the tooth?

The doc had prepped the linguals to cover most of the entire surface...maybe except a mm or so from the incisal edge. The patient had fairly translucent teeth which further exacerbated the problem.

In regards to the porcelain slurry, have you just tried glazing the undersides of the wings and etching that?[/QUOTE]

I was recently (june 2011) in San Diego for the Quintessance Symposium on Ceramics. Dr. Marcus Blatz spoke on this. He showed research that a single winged retainer maryland bridge has 92% success rate over double winged retainer bridges at 76%.......success defined as a wing separating from abutment. The internal surface must be AlO2 sanded(lightly),ceramic primer from Clearfil applied to sanded surface, and cemented with Panavia. He showed several SEM images displaying the quality of adhesion.

Hope it works out !! Orr

 

[paulg100]

"The doc had prepped the linguals to cover most of the entire surface...maybe except a mm or so from the incisal edge"

Thats why it greyed out. Only taking the wing 1/2 way up the palatal normally solves the problem, even with translucent teeth.

"In regards to the porcelain slurry, have you just tried glazing the undersides of the wings and etching that?"

Nope although i know thats what some others do.

 

[k2 Ceramic Studio]

"The doc had prepped the linguals to cover most of the entire surface...maybe except a mm or so from the incisal edge"

Thats why it greyed out. Only taking the wing 1/2 way up the palatal normally solves the problem, even with translucent teeth.

"In regards to the porcelain slurry, have you just tried glazing the undersides of the wings and etching that?"

Nope although i know thats what some others do.

I was told that the glaze technique was not as good as the porcelain slurry tech because the glaze liquid is mainly just a carrier and you are reliant on the powder/past that you mix into the liquid to give you an even layer. we do all of ours after the glaze cycle using the emax/initial add on material, we give the wing/wings a 0.7mm border then have a 0.085 mm cement gap, so far so good. Lol

 

[paulg100]

"I was told that the glaze technique was not as good as the porcelain slurry tech"

that was my opinion also. thats why i do it the slurry way.

In theory you would think firing the liner there would be the most effective, but im not sure how well that etches.

milling centers are using the bonder method now for ZR inlays and onlays etc.

I was told at a lecture at straumann that these bonders (eg monobond plus) are not very effective on zr. I need to get some time to do a bit of research on that, if anyone else already has info or gets the time then please post popcorn

At the moment im telling clients asking for ZR inlays and onlays to use Emax instead.

 

[disturbed]

im not sure how well that etches.

milling centers are using the bonder method now for ZR inlays and onlays etc.

I was told at a lecture at straumann that these bonders (eg monobond plus) are not very effective on zr. I need to get some time to do a bit of research on that, if anyone else already has info or gets the time then please post popcorn

hmm.. bonders not effective on Zr you say? hmmm....I have done some research on the bond of porc. to Zr.. you might read a few of my posts..lol.. you can etch the bonder but the bonder will NOT chemically bond to Zr, mechanical ONLY. the bonder may etch but without a large area (full crown) I believe the "bonder" will delam from the ZR and fail.

 

[CoolHandLuke]

i dont think delamination is at play here disturbed; this was pointed out at least once by bobby orr with the spray liner.

i think theyre speaking of the adhesion of the bridge to the teeth and to be perfectly honest as i am never in the loop at that stage of the game i can't make any insight into what our dentists do. although, i can tell you we're in Toronto, so theyre probably useing gorilla glue LOL

in any case for zirc marylands we use opacious high strength zirconia which we design over the FULL lingual despite the "prep" given. tiny nubby wings always break (as we've repeatedly demonstrated) and create bad shades as the zirconia is highly opacious.

we will not use translucent zirc and sacrifice strength - not gonna happen. the liner to adhere the porc works to disguise the pontic and blend the adjacent abutments so shade shouldnt be an issue.

 

[PDC]

"I was told that the glaze technique was not as good as the porcelain slurry tech"

that was my opinion also. thats why i do it the slurry way.

In theory you would think firing the liner there would be the most effective, but im not sure how well that etches.

milling centers are using the bonder method now for ZR inlays and onlays etc.

Thanks for the info. I did try to etch the zirliner, but it won't etch. I like the slurry idea, but it would appear that you would have to very careful with thickness and placement. MB's are just a pain from fit to shading.

 

[rkm rdt]

Not if you make them in Emax.

 

[PDC]

Not if you make them in Emax.

I do have one out there like that. It has been in the mouth for over a year now and the esthetics were dynamite.

 

[paulg100]

"did try to etch the zirliner, but it won't etch"

Yep thought that might be the case.

"you can etch the bonder but the bonder will NOT chemically bond to Zr, mechanical ONLY"

Yep thats why it isnt meant to be that effecttive on ZR.
And still dont know if the the contact surface being stuck to the tooth will etch.

"I like the slurry idea, but it would appear that you would have to very careful with thickness and placement"

Yep you do, it does result in a slighty non-positive fit of the wing, but its the only effective way we have right now to my knowledge.

 

[PDC]

Not if you make them in Emax.

This is a pic of 2 maryland bridges (#7 & #10) I did 2 yrs. ago which were pressed out of Emax. The value is a little low but considering this was an out of town doc and I only had pics to go by, I was happy with the result and so was the patient. Still functioning!

 

[rkm rdt]

Excellent job!

I have had no failures with my Emax marylands.However I do prefer a modified path of insertion where the abutment wall line angles are prepped to a lingual taper. I try to "beef" up the cingulum and recontour the connectors where the bite allows.

I always predesign the study models and submit to the Dr prior to prepping the teeth.

There is no need to prep the linguals as if they were metal unless you are replace a metal MB.

I have made these for NHL hockey players with sucess.

 

[PDC]

Excellent job!

I have had no failures with my Emax marylands.However I do prefer a modified path of insertion where the abutment wall line angles are prepped to a lingual taper. I try to "beef" up the cingulum and recontour the connectors where the bite allows.

That's a good tip about the wall line angles...I could see where we could get a lot more strength where it counts the most. Thanks.

 

[amadent]

This is a pic of 2 maryland bridges (#7 & #10) I did 2 yrs. ago which were pressed out of Emax. The value is a little low but considering this was an out of town doc and I only had pics to go by, I was happy with the result and so was the patient. Still functioning!

nice job- pontics look like they are growing out of the tissue
from speaking distance no one would know they are restorations

Greg Amendola MDT