Fusing IO Scans with 3D X-rays
To fuse the selected IO scan with the 3D X-ray in the 3D patient workspace:
Click IO Scan on the menu bar.
Click 
Fuse with 3D X-ray.
Check the alignment by scrolling through the reslice viewer.
Use the Bone threshold slider to make it easier to check the alignment.
The shape of the IO scan (in pink) should be aligned with the 3D X-ray's reslice.
Click Edit upper alignment or Edit lower alignment to indicate corresponding points to adjust the alignment manually. Follow the instructions in the viewers and indicate each of the requested points alternately on the 3D X-ray and on the IO scan. Click Done to calculate the alignment based on the indicated points.
If the alignment of a jaw fails, a warning dialog is shown, allowing you to start indicating corresponding points straightaway.
To improve the result, try the following:
In Patient orientation, verify the occlusal plane. Adjust if needed.
In OPG/PAN curve, reindicate the upper and the lower arches.
Make sure the IO Scan's occlusal plane is horizontal.
Click Finish.
The aligned IO scans are added to the diagnosis. They are shown in all 3D viewers and reslice viewers of the 3D patient and tooth (if available) workspace.