No. An additional calibration will not be required. All sensor session information, including the calibration information, is stored on the Dexcom transmitter, not on the devices connected to it.
NOTE: This is different from the Dexcom G4 CGM, where each connected device has to be calibrated separately.
Important note about Dexcom support:
For "no restarts" alert or physical problems with your sensor or transmitter, such as bleeding, bruising, skin reaction, adhesive issues, applicator issues, or broken wires, you should contact Dexcom using one of the options at dexcom.com/contact.
If you have paired a Dexcom CGM with your Tandem insulin pump, and your question isn't answered in this help section, you should contact Tandem customer technical support for all other issues by calling (877) 801-6901.