“…Two of the studies were conducted only with women [16,34], and two studies did not mention the gender distribution [29,31]. In most of the studies [4,17,[28][29][30]37,38,[40][41][42], the participants were patients at a university periodontal clinic or private dental practice. Five studies [31,33,35,36,41] were epidemiological surveys involving the residents in a particular area or a randomly selected general population.…”