**1. Introduction**

Periodontitis is a globally widespread pathology of the human oral cavity. Approximately 10% of the global adult population is highly vulnerable to severe periodontitis, and 10–15% appears to be completely resistant to it, while the remainder varies between these two situations [1]. Periodontitis is a major public health problem due to its high prevalence, as well as because it may lead to tooth loss and disability, negatively affect chewing function and aesthetics, be a source of social inequality, and impair the quality of life. Periodontitis accounts for a substantial proportion of edentulism and masticatory dysfunction, results in significant dental care costs, and has a plausible negative impact on general health [2].
