The Dons enjoyed total control of the first half and Luke Chadwick and Dean Lewington both went close before Carrington put them ahead, nipping in ahead of keeper Jamie Jones to nod in Aaron Wilbraham's clever chip for his fifth goal of the season.
Chadwick should have doubled the Dons' lead soon after the break but his low shot was well saved by Jones after Carrington's quick free-kick had sent him clear.
Mark Randall and Jermaine Easter both blasted efforts narrowly wide for the hosts before Lewington headed Peter Leven's free-kick just over the bar.
Leyton Orient finally applied some pressure in the closing stages and substitute James Scowcroft's fierce 15-yard volley was saved at full-stretch by keeper Willy Gueret 10 minutes from the end - the visitors' first shot on target.
Source: Team Talk