, I finish the design and without doing a really good double check to make sure all the crowns are actually on the bridge, I just nested and milled
This is the software's fault
The reason the pontics weren't connected to the merged resto is you didn't connect them. If you were doing something other than a wax up/copy mill for that bridge you would have been prompted to add the connectors in the design process.
One way to fix this without deleting merged parts. <---- this is a way to make your situation worse if you are not familiar with the process.
Save each pontic separately as stl. Choose the top option in the prompt window for which coordinates to save in.
In expert mode, add remove mesh, since you don't have a preop already, import those pontic stl files you just saved as preop mesh. After importing, still in expert mode right click one of the pontics, select free form scan data. Add to the mesial of each pontic to make a nice broad connector. Make certain the free form addition intersects the distal of your bridge.
Once you are happy with the connector size save the cantilever pontics again as stl in the same coordinates.
Continuing in expert mode, right click on the bridge, select free form restoration.
In the free form window navigate to ATT,
in the library drop down menu scroll to 'add from file'.
Navigate to the CAD Data Pt. folder you saved those pontics in if it doesn't open automatically.
Double click on the pontic file. Click apply, click ok or next. When prompted select yes when asked if you want to save your free form changes. The software will recalculate the restoration with the pontics attached and save a merged bridge.
There are several other ways and/or shortcuts to do this, but this is a pretty safe way until you are more familiar with the steps.
People like to gripe about the exowiki and how brief or outdated it is. It explains all the basic software functions pretty well and concisely. I still reference it when I haven't done a certain type of whatever in a long while.