Oral microbiota in human health and disease: A perspective

Abstract

The evolution of medical knowledge about oral microbiota has increased awareness of its important role for the entire human body health. A wide range of microbial species colonizing the oral cavity interact both with each other and with their host through complex pathways. Usually, these interactions lead to a harmonious coexistence (i.e. eubiosis). However, several factors - including diet, poor oral hygiene, tobacco smoking, and certain medications, among others - can disrupt this weak homeostatic balance (i.e. dysbiosis) with potential implications on both oral (i.e. development of caries and periodontal disease) and systemic health. This article is thus aimed at providing an overview on the importance of oral microbiota in mediating several physiological and pathological conditions affecting human health. In this context, strategies based on oral hygiene and diet as well as the role of probiotics supplementation are discussed.

Keywords: Human microbiota; dental caries; diet; microbiome; oral biofilm; oral dysbiosis; oral health; periodontitis; probiotics.

Figure 1.

The main relative % phyla of oral microbiota stored in HOMD. Source: HOMD, http://www.homd.org/.

Figure 2.

The main stages of the biofilm formation process on the tooth surface. Source: Charitos IA.

Figure 3.

Percentages of different genera recovered from the whole saliva of healthy adults.

Figure 4.

The diversity and richness of microbial communities are related to caries risk. Surfaces and positions with the highest variety and richness that are more sensitive to caries. When caries develops, the acidic environment reduces the variety and richness of local microbes. Source: Charitos IA.

Figure 5.

The oral microbiota dysbiosis lead the overpopulation of certain bacterial strains but also fungi such as Candida albicans which in turn causes the local “Inflammation Dysbiosis Cycle condition.” Source: Charitos IA.