regular silicone (for windows/bathroom) contains fungicides to keep the silicone from getting moldy, i dont know how harmful these are but people avoid them.

aquarium silicone is just fine. if its fine for fish that swim in water which is in contact with the silicone 24/7, then its fine for reptiles as well.

BTW the strong smell of silicone as it dries, thats acetic acid, basically concentrated vinegar. its safe once that smell is gone.