Dean joined the Shots in the summer from Rushden and Diamonds. However, injury and the form of other players have restricted him to just nine appearances, the last of which was away at Chesterfield in October.
Manager Gary Waddock said, "Dean needs first team matches at the stage of his career that he is at. We have had a couple of conversations and this loan spell will be beneficial for him because he does figure in our plans.
"Dean has been extremely professional in the way that he has conducted himself and I hope that it all goes well for him."