The makers of Shredded Wheat breakfast cereal would regard the shredding machine as very much the new-kid-on-the-block when it comes to how long the word 'shredded' has been in popular use.
I can't see how much difference there is in the pronunciation of/getting one's tongue around 'shredded' with 3 d's, versus 'dreaded' with 2 d's
Now comes the trouble: no dreaded, so -
1.I dread going
2.I dread going
Have I been, or have I still to go for my dentist's appointment?
1. I dread going to the dentist so I only go every two years.
2. I dreaded going to the dentist this time because I was sure he would have to use the drill.
I dreaded going to the dentist as a child.
I don't think that anyone would be agast if you used "shred" for past tense.
It will go completely unnoticed by the likes of a Jerry Springer show audience.