Just as an information for potential answerers: this question has also been asked on TeX.sx.
I do not really know TeXnicCenter but following the comments on the linked page the answer seems to be: no, there is no such button, yet.
Statistics: Posted by cgnieder — Thu Feb 21, 2013 12:11 am
after adding a new reference with JabRef, I need to close and restart TeXnicCenter (TXC) before the entries in the literature database menu of TXC get updated. Isn’t there a button for refreshing the literature database, so I will see my changes right away?
Statistics: Posted by babostyle — Wed Feb 20, 2013 6:43 am