Easter netted a 61st minute tap-in before Wilbraham scored his first goal of the season in the last minute to condemn the Gills to their fourth successive defeat on the road.
Home goalkeeper Willy Gueret saved fierce long-range strikes from Curtis Weston and Andy Barcham before Mark Bentley's looping header dropped just wide as Gillingham bossed the early stages.
But the Dons found their feet and, after Mathias Doumbe had headed against the post in the 43rd minute, Easter put them ahead just after the hour mark.
Tricky winger Jason Puncheon wriggled his way to the byline and crossed perfectly for the in-form Easter to slot home his 10th goal of the season from five yards.
Gillingham probed for an equaliser late on but they lacked the guile to unlock a well-drilled Dons defence, before Wilbraham lashed Puncheon's pass into the top corner from 12 yards to wrap up the Dons' win in fine style.