“…Others may have existed, but we have no elements to evoke them, such as changes in biofilms formations [73], plaque-induced gingivitis [74] and gene expression, which benefit today from stem cells implantation [75,76]. These three processes concern a general process of diminished immunity which can be evoked in the face of certain chronic infectious pathologies: (1) an addiction to tobacco in the 19th century associated with an increase in the consumption of black tea and no longer green tea, which was drunk in the 18th century [77]. While some people smoked in the 18th century, in the 19th century, tobacco became widespread [77] and a large part of the population, even older children, became addicted to it [78].…”