My SO is a DDS and has been back to practicing for over 3 months now. Her office has had no infections. My guess is the enhanced pre-screening, the closed wait area, no non-patients allowed, and all of the additional requirements of PPE have contributed very positively to keeping that infection potential suppressed. Staff have been tested a number of time due to concerns but they are strictly following the outlined protocol and have some enhanced requirements the owners have instituted to help keep it that way. This is in the US.