Sanford hit 9-of-9 from the floor, all three of his 3-point attempts and 2- of-2 from the stripe in a reserve role for Dayton (23-9), which will take on fourth-seeded Saint Joseph's on Friday in the quarters.
Devin Oliver had 17 points and 11 rebounds and Jordan Sibert scored 14 for the Flyers, winners in nine of 10.
Branden Frazier netted 30 points for Fordham (10-21), which edged George Mason, 70-67, in Wednesday's play-in game to reach this point. Bryan Smith and Jon Severe contributed 15 points apiece.
Dayton led 50-31 after a dominant first half but tripped up early in the second, allowing the Rams to pull within five points on multiple occasions midway through the stanza.
Devon Scott's jumper with 5 1/2 minutes to go restored a double-digit margin, and Dayton cruised the rest of the way.