I doubt the wormhole, wouldn't it have opened?
After "Destiny", subspace signals could get through without making the wormhole mouth do its thing. Before that, though (and "Jem'Hadar" does come before), one would think that the hole would indeed have to open.
Timo Saloniemi
But only after Destiny. It was caused by the minerals of the comet 'burning' the mouth of the temple gates according to dialogue.