To search for the most recently created forum entries go to the forum search page and enter how many days back you want to search in the Date-field. Then change the Order to "Creation Date (new first)" and Search for that.
 
You can use the select-option "Latest forum posts" from the Dragon bookmarks.
 
However, it is not possible to distinguish between new posts (unread) or read posts, but at least you have the candidates to check.
 
In case you want to bookmark such a request, you can use the following link: DGS forums recent posts (30d)