Connector mm2

[McTeeth]

Hey Guys,

Is 9mm2 still the standard for area on zirconia connectors for 1100 MPa? It sure is annoying on some cases to try and achieve this without creating a monster connector. Better than e.max tho

,

 

[CoolHandLuke]

yes but shape is more important than size.

tall > wide

no teardrop shapes either. good ovals or ellipses or if constrained in this way, aim for round triangles instead

 

[McTeeth]

yes but shape is more important than size.

tall > wide

no teardrop shapes either. good ovals or ellipses or if constrained in this way, aim for round triangles instead

Round Triangles?

 

[CoolHandLuke]

or if you are down for a laugh (and slightly Off topic but not much)

 

[Getoothachopper]

or if you are down for a laugh (and slightly Off topic but not much)

I love QI .

 

[Smilelist]

yes but shape is more important than size.

tall > wide

no teardrop shapes either. good ovals or ellipses or if constrained in this way, aim for round triangles instead

Does this compare to old school PFM fysics that concerning connector strenght height relates to width as 2 to 1. So for every mm in height you need 2 mm width for equal strengh. So try to maximize your height.


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[Kaypan]

I don't think it is that easy, to say 9mm is a good zirconia connector. It all depends on the case. Is it good enough for a three unit anterior bridge, yes most likely. Is it good enough for a five unit posterior bridge with two pontics? I would absolutely say no. I always like to secure the case for the future, the stronger the better within reasonable limits. As for shape: if you double the width of the connector, you double the strenght. If you double the height of the connector, you get 8x the strenght. In regards of vertical forces.

 

[Smilelist]

I don't think it is that easy, to say 9mm is a good zirconia connector. It all depends on the case. Is it good enough for a three unit anterior bridge, yes most likely. Is it good enough for a five unit posterior bridge with two pontics? I would absolutely say no. I always like to secure the case for the future, the stronger the better within reasonable limits. As for shape: if you double the width of the connector, you double the strenght. If you double the height of the connector, you get 8x the strenght. In regards of vertical forces.

Kaypan I agree but one should also considere ocllusal and functional ware. Q; are you sure about the statement 8x the strenght ?
So If I make a connector 1 mm high and 1 mm wide it gives me 8. x 2 = 16 off what in strenght ?


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[Kaypan]

Kaypan I agree but one should also considere ocllusal and functional ware. Q; are you sure about the statement 8x the strenght ?
So If I make a connector 1 mm high and 1 mm wide it gives me 8. x 2 = 16 off what in strenght ?


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Well, I understand why that 8x strenght seems unbelieveable. I must have been taught in school or somewhere, but I googled it now and found this on Ivoclars website.
These kind of forces are measured in newton centimeter(N-cm). I think max. load forces in the posterior area is 700 newtons. Then you must consider span lenght, hydrothermic aging,flex and so on. It is a impossible calculation in our profession, with so many variables(some you can´t measure). Thats why I rather go heavy on a connector design. And extremely important to round up the design as CoolHandLuke said.

 

[rkm rdt]

I don't use the connector anymore.
Full contour connections only.

 

[Smilelist]

I don't use the connector anymore.
Full contour connections only.

Can you tell us why ? I 'encounterd' some 3 unit broking bridges in HT Zirkonia :-(

 

[cadfan]

one bridge member 9 mm2 two and more 12mm2 cantilever 14 mm2 in the front a bit less

 

[rkm rdt]

Can you tell us why ? I 'encounterd' some 3 unit broking bridges in HT Zirkonia :-(

Full contour allows me to beef up the connection and there is no need for porcelain under the pontic.