🦷 Milling Hybrid Abutments & Screw-Retained Restorations in MillBox
🎥 Start Here: Watch the Introductory Video
Before beginning your workflow for Hybrid Abutments or Screw-Retained Crowns/Bridges, we highly recommend watching the instructional introductory video available [HERE].
This video provides a visual overview of the process and best practices.
⌨️ Use Shortcut Keys to Save Time
MillBox includes a variety of shortcut keys that can significantly speed up your workflow—especially when working with Hybrid Abutment cases. Familiarizing yourself with these shortcuts can reduce processing time and improve efficiency.
You can access the latest list of MillBox shortcut keys [HERE].
🧠 Recognize Hybrid Abutments Correctly
When importing abutments into MillBox, it’s important to correctly identify the type:
If the abutment does not have an internal or external hexed or tri-lobed interface, it should be treated as a Screw-Retained Crown or Hybrid Abutment.
Examples of Hexed or Tri-Lobe Abutments:
Examples of Hybrid Abutment / Screw-Retained Crown / Screw-Retained Bridge:
⚠️ Important: Correct Object Type Matters
Always ensure that imported objects are assigned the correct type.
Incorrect object types can prevent MillBox from detecting abutment base curves, leading to skipped operations or unpredictable milling results.
If you're unsure, refer to the guide: Understanding Curves / Surfaces and Restoration Types.
Verify These Key Elements When Importing:
For successful milling of a Hybrid Abutment, the following three elements must be present and correctly configured:
🔴 Red Caps (Screw-Access Hole Covers)
Presence & Placement:
Ensure red caps are present at both the top and bottom of the screw-access hole.
Functionality:
These caps prevent tool entry during roughing and finishing. They are automatically disabled during the drilling operation to allow access to the screw channel.
🌸 Base Curve / Margin Lines (Abutment Base Definition)
2019 or Newer:
Look for a pink curve at the base of the abutment.
2018 or Earlier:
Look for a gray cap at the margin/abutment base.
🟢 Drilling Axis Curve
Presence:
This curve defines the start and stop points for drilling.
Color Coding:
2019 or Newer: Green
2018 or Earlier: Purple or Magenta
Functionality:
Must extend from the top to the bottom of the screw-access channel.
PRO TIP:
Press “9” once on your keyboard to toggle translucency
Press “9” twice to view “Mesh Mode”
Press “9” or “0” to return to normal view.
Toggle Visual Layers for Inspection
Once your restoration is imported, verify that all required surfaces and curves are present and correctly placed
👁️ How to View Surfaces and Curves
Go to Tools > Visual Layers
Use:
Show / Hide Holes – Toggles on / off the visual layer of the red caps
Show / Hide Cavity Cap – Toggles on / off the visual layer of the Grey Caps on the Margins
.
In some cases, you may not be able to clearly see the base of the abutment with the gray cap turned on. You can either delete it using the “delete curves and surfaces” tool, or just hide it from view as you detect the margin / base using the Tools > Show/Hide menu.
NOTE:
If the gray CAP is incorrectly detected / placed, you will need to re-place it in the correct location by re-detecting the base of the Hybrid Abutment.
For this you will use the Automatic or Manual Margin Line Detection tools available under Tools > Curves & Surfaces
Correct Surface & Curve Issues
Once your restoration is imported, verify that all required surfaces and curves are present and correctly placed.
🧹 When and Why to Delete Curves or Caps
You may need to delete curves or caps if they are:
Incorrectly detected
Misaligned
Obstructing visibility during margin detection
🛠️ How to Delete Curves or Caps
Go to Tools.
Select Delete Curves and Cylinder Caps.
Click the cap or curve you want to remove.
Example:
Redetect or Manually Define Key Features
Margin Line Detection
Go to Tools > Curves and Surfaces
Select Margin Line Detection and click where the margin should be
Or Manually draw the margin by clicking around its edge:
Cylinder Detection (Drilling Axis)
Go to Tools > Curves and Surfaces
Select Cylinder Detection
Click inside the cylinder on the restoration
Add Caps to Cylinder
Go to Tools > Curves and Surfaces
Select Add Caps to Cylinder
Click inside the cylinder to apply red caps
Change Cylinder Size
Go to Tools > Curves and Surfaces
Select Change Cylinder Size
Click the drilling axis line to adjust diameter, length, or position
Final Step: Run Kinematic Simulation
After calculation, if there are any doubts, run the Kinematic Simulation to verify that all curves and surfaces are functioning correctly and the milling behavior is accurate.
Summary
By following this structured workflow, you’ll ensure accurate detection, classification, and milling of Hybrid Abutments and Screw-Retained Restorations in MillBox.