I have a hypothesis that Dennis’s parents were William Roberts and Polly Turpin... and that Polly Turpin is actually a Tarter. She shows up near a number of Roberts/Tarters in records, Chrisley Tarter witnessed the wedding of William and Polly, Chrisley Tarter entered tax obligations for William Roberts, and Tarters purchased much of William Roberts property when it was auctioned after his passing in 1836. Also... in the 1840 census for Polly Roberts, the name “Robert Sayers” was written, scratched out, and replaced with “Polly Roberts”. (Robert Sayers was married to a “Polly Tarter”).
I have a lot of source images uploaded on the Dennis/Polly/William profiles for tax records, I&A, and settlement that include these Tarter connections... if any of it is helpful or interesting in your own search.