Exporting from Romexis
In Planmeca Romexis, select the 3D study and choose Export → DICOM. Pick the option "Export as DICOMDIR" or "Export folder". Romexis creates a folder that typically contains a DICOMDIR file and an IMAGES subfolder with numbered .dcm slices.
Zip the whole folder and upload. CBCTHub reads DICOMDIR and also falls back to parsing loose slices if DICOMDIR is missing.
Romexis Viewer vs CBCTHub for distribution
Romexis Viewer is free but Windows-only and has to be installed on every referring dentist's machine. Sending it by email hits attachment limits. Burning it to CD is a 2010 workflow.
CBCTHub skips all that. The dentist clicks a link, the exam opens, they read it, measure, screenshot and sign off. Zero install on the receiving side.