“…[3,4,12,19–21,27–30,32,34,35,42,46,47,50,51,54,57]. Three studies [43,44,48] detected significant increases of gram-negative bacteria, respectively, at 3 and 6 months, followed by a decrease at 6 and 12 months. Ten studies [10,20,21,26,30,37,41,43,44,48] detected an increase in the percentage of gram-bacteria and A. actinomycetemcomitans .…”