The centre-half has been captain of the Gills for the past two seasons since switching to Priestfield from Bournemouth, playing 95 games in all competitions.
However, Peter Taylor opted to make him available for a stint elsewhere and the League Two Dons have swooped to take him on a two-month deal - although he cannot feature in cup competitions.
Dons boss Neal Ardley believes the club have found the perfect replacement for Andy Frampton, who suffered a broken ankle in training last week.
"We had a devastating blow with Andy's injury and we looked at various options, including bringing in a younger, athletic defender," Ardley told the club's official website.
"But we felt that we still needed someone with similar qualities to Andy and the leadership that he brings.
"Adam understands the game and is a leader of men.
"He is a great talker too and is also a left footer the same as Andy so he is a great signing for us."
The 34-year-old centre-back brings with him a wealth of experience having made more than 600 Football League appearances for the likes of Plymouth, Leyton Orient and Southend.