Today’s lesson is about designing a post and core. The post and core, which was made with hands only in the past, is now able to be made with CAD/CAM. Many people are wondering how to make the zirconia post and core with CAD/CAM. I will demonstrate how to scan and design the post and core, and how to design the suprastructure.
Prepare an impression with the stone model for the post and core. I am going to set the model at tooth number 13.
Create a project and name it as “post test”. Select tooth number 13. Choose Inlay and Zirconia for the material. Open ScanApp and select the Solid model.
Place the model and scan it.
Trim the unnecessary parts.
Don’t move on.
Impression Scanning in Additional Scan and Match Stage
Click Additional Scan and Match. Proceed the impression scan at the additional scan and match stage.
Click Auto-brightness. Since it is an impression, negative and positive should be reversed. Click Reverse and scan.
Three Points Matching - Impression Scan Data & Model Scan Data
Match the data with three points.
Begin the build. As you can see, the root is clearly scanned inside.
Designing the Post and Core
Move on to excoad to design the post and core with this data. This stage is drawing the margin. The post and core margins are a little bit inside.
Click Next to go to the “Insertion Direction” stage.
When setting the insertion direction, make sure that there is no undercut. If there is an undercut, this route will block out. Click Next.
The post and core is all done.
Save the post and core.
Save the post and core separately once more.
The next step is designing the suprastructure.
Change to Anatomic crown and click save.
Click Load scan data only. I will first edit the scanned data.
In Expert mode, delete the deep part.
I am selecting the inner part of the post and deleting it. Then, close the hole.
If there is a problem with the data, you can also modify it as shown in the image below.
Draw the margin after filling the hole.
Place a tooth.
Next, exocad will ask if you want to delete the inlay file.
Do not delete the inlay file. Let’s go to Free-form restorations to load the inlay file that I worked on earlier.
Do not delete the inlay file. As you can see, the inner part is clearly removed.
You may work like this. You can make the post and core and the crown at once, just like one-step milling. Today’s lecture is a little complicated and long. Thank you for reading my lecture. I hope my lecture is helpful for you.