“…The agreement between the eligibility of studies was considered excellent (k= 0.91) [11]. Among the selected studies, published between 1989 and 2014, 8 were conducted in Europe [14,15,18,19,25,28,29,32], 5 were conducted in Asia [13,16,23,24,30] and 100 were conducted in America [17, 20-22, 26, 27, 31, 33-35]. Overall, the occurrence of dry mouth was investigated in 1979 in people with diabetes (cases) and 1667 controls, whereas in 15 articles, the authors subdivided the outcome into types 1 and 2 diabetes mellitus (Table 1).…”