Well, it's a retcon, but it's out of necessity: Tomiko Suzuki, who voiced the Namekian brothers Dende and Cargo, passed away some years back. So in the newly re-dubbed and re-mixed Dragon Ball Kai, Aya Hirano ( The Melancholy of Haruhi Suzumiya's Haruhi, Lucky Star's Konata) and Satomi Satou ( K-On!'s Ritsu, Hatsukoi Limited's Yuu) will replace Suzuki.
Other switcheroos have been made, but this will be the first that features prominent seiyuu names. Still, I wonder: how will Dragon Ball's GAR manly battle fanatics react to the sudden inclusion of seiyuu best known for their more moe roles?
Also worth noting, this isn't Hirano's first Dragon Ball-related voice acting gig: she actually dubbed over Emmy Rossum's voice as Bulma in Dragon Ball Evolution, which was better received overseas than in the US.