I use pubmed, Cochrane, goggle scholar when I search for papers but I wonder if most researchers use more databases especially when doing systematic reviews.
Those are the main ones but depending on the subject matter you can also try Ovid, Scopus, PsycINFO, ERIC, and maybe some grey literature sources. This website has more information on grey lit: http://www.greylit.org/
If you give your field of work ( might be Oral Medicine and Periodontology) it will be easier for the RG members to suggest appropriate databases of publications.