Calling ActiveX control method from another thread

I have an ActiveX control on a Windows form that provides OPC client
functionality. The control has no visible elements. I would like to write a
class which uses the control to pass data to an OPC server based on a
timer...say every 5 seconds write data to the server. I know normally, I'd
use the Invoke member to access control properties from a separate thread.
However, if no other thread is accessing the control and there are no
visible elements of the control, is it still necessary to use Invoke or can
I safely call the control's methods directly?

Thanks

Dave Taylor
PERI