Hybrid Bar Zirconia Fractured

[Mercury456]

Hello DLN,

A doctor sent the lab images of a a zirconia hybrid bar case we did for him a few months ago. The zirconia has fractured down the midline and around #8.

We 'retreaded' an old bar for the patient in zirconia because she kept breaking the anterior teeth when it was done in acrylic. We thought using zirconia would solve the problem. I hope the pictures can give some insight into our lab processes

We used Katana STML sintered at manufacturers specs with a .7mm minimum thickness setting all as one piece. Final countouring was done without the use of water

We hand milled a chamfered shoulder on the lingual aspect of the bar and bonded with RelyX UniCem Automix Cement.

We used light cure Gradia Composite for the gums.

Any ideas regarding why this is happened would be appreciated.

What could we try to improve the success of these types of cases?

Should we take a different approach?

 

[2thm8kr]

Are you using thin diamond disk to separate between 8&9 or any other embrasures?

 

[ps2thtec]

STML is only 750mp. Would you try this in cubeX?
May need ML, 1100mp. .?

 

[CreDes]

Two things that I immediately notice are the .7mm thickness and material choice. With something like this I want thick and strong.

 

[rkm rdt]

 

[kcdt]

Hello DLN,

A doctor sent the lab images of a a zirconia hybrid bar case we did for him a few months ago. The zirconia has fractured down the midline and around #8.

We 'retreaded' an old bar for the patient in zirconia because she kept breaking the anterior teeth when it was done in acrylic. We thought using zirconia would solve the problem. I hope the pictures can give some insight into our lab processes

We used Katana STML sintered at manufacturers specs with a .7mm minimum thickness setting all as one piece. Final countouring was done without the use of water

We hand milled a chamfered shoulder on the lingual aspect of the bar and bonded with RelyX UniCem Automix Cement.

We used light cure Gradia Composite for the gums.

Any ideas regarding why this is happened would be appreciated.

What could we try to improve the success of these types of cases?

Should we take a different approach?

Did you make a verification jig? In stone?

 

[RCKSTR]

"Final contouring was done without the use of water "

This can cause micro cracks you cant see that will develop in to a large crack

 

[CoolHandLuke]

Hello DLN,

A doctor sent the lab images of a a zirconia hybrid bar case we did for him a few months ago. The zirconia has fractured down the midline and around #8.

We 'retreaded' an old bar for the patient in zirconia because she kept breaking the anterior teeth when it was done in acrylic. We thought using zirconia would solve the problem. I hope the pictures can give some insight into our lab processes

We used Katana STML sintered at manufacturers specs with a .7mm minimum thickness setting all as one piece. Final countouring was done without the use of water

We hand milled a chamfered shoulder on the lingual aspect of the bar and bonded with RelyX UniCem Automix Cement.

We used light cure Gradia Composite for the gums.

Any ideas regarding why this is happened would be appreciated.

What could we try to improve the success of these types of cases?

Should we take a different approach?

yes.

1. use water. duh.
2. for big cases like this you'll want minimum 1mm.
3. revise your use of the built-in virtual articulator in your design software. a break like this can be avoided when proper movements are maintained

 

[grantoz]

can you repost the pictures i cant open them for some reason

 

[CoolHandLuke]

 

[zero_zero]

Is there a Ti bar underneath?

Sent from my SM-G930W8 using Tapatalk

 

[grantoz]

in another thread i talked about doing courses so you dont have these problems,if you did have some proper training you would know what you did wrong, honestly you shouldnt be doing this stuff.we have to remember the patient its not fair to them to say i will make this or that when you dont know what you are doing on top of that you are going to loose the dentist because you dont have any credibility.my staff and i just looked at this and burst out laughing we could see 10 things wrong straight away.Im sorry to be so harsh but im hoping you will go and find out how to do these bridges properly so the patient does not get injured and you dont get sued.