I see "digitally mastered" "remastered" as meaning essentially the same thing (transferring film to the digital domain). By definition all DVDs are digitally mastered.
"Restoration" is the process of returning a film to its original condition (or close to it as possible). A film can be digitally remastered but not restored. Restoration is very expensive and is typcially done for major studio releases (Fox, Warner, Paramount) and not done for the $1 DVDs, Alpha type releases.