I feel like they affect it a tiny bit, because this season I just finished my provisionals with a 4/6 score and I placed Silver II in Solo/Duo Queue. I was Silver II in Dynamic Queue at the end of last season, and I did not play ranked in the preseason. I had only played normals up until I decided to do my provisionals. In Flex Queue I went 6/4 and placed Silver I, which is even higher than my Dynamic Queue ranking!
I remember the Boards being in uproar about how low they placed after the soft reset, and yet here I am the same rank in Solo/Duo and a rank higher in Flex with average provisional scores. Do you think that all the normals I played from the soft reset until now could have brought my MMR back to what it was before the reset?