**2. Oral cavity microbiome**

Immediately after birth, the sterile mouth cavity of the newborn individual mediates the contact between the internal and external environments and, at this time, also its colonisation by microorganisms commences. After several days, the microbiota characteristic of the oral cavity becomes stabilised [5]. In the process of colonisation of the mouth cavity of newborns, streptococci are acquired the first. Over time, the diversity of populating microorganisms grows until the individual acquires certain microbiota the stability of which depends on compensation mechanisms ensuring suitable conditions in the mouth cavity. Mucosa and teeth in the oral cavity come into constant contact with the exogenous microbiota, and the health state of dentition is also affected by proportions of individual groups of microorganisms. Some factors, for example unsuitable diet, can irreversibly affect the homeostasis of the oral ecosystem and subsequently lead to propagation of pathological changes in the oral cavity [6].

Although the oral microbiota contains bacteria, fungi, viruses and archaea, research has focused mostly on oral bacterial populations present in the highest numbers [7]. Fungi as one of the components of the oral microbiota were identified by pyrosequencing with focus on RNA, which exhibits high species variability. Peterson et al. [8] reported that the number of fungal species in the oral microbiota ranges from 9 to 23.

Molecular microbiology techniques based on 16S rRNA allowed scientists to describe more than 700 bacterial species present in the oral cavity of humans. More than 50% of bacterial species were not cultivated and thus their role in the oral microbial ecology has not been explained. It was assessed that approximately 1000 bacterial species are capable of stable existence in the mouth of humans, while each man can harbour 50–200 species of this diverse spectrum [9]. Many species are found temporarily in the saliva or as a part of biofilms formed on teeth or mucosa. Analysis of biodiversity in the mouth cavity showed that the number of oral phylotypes is considerably undervalued. Quantification of oral microbiota of humans was performed by metagenomics of unique phylotypes using pyrosequencing 454 and sequencing by Ilumina technology. This quantification method confirmed 668 bacterial phylotypes in microbiota of one plaque, which is considerably more than the numbers published in the previous studies. Similar sequencing technique detected

**281**

**Figure 1.**

*coloured blue.*

*Oral Microbiota from the Stomatology Perspective DOI: http://dx.doi.org/10.5772/intechopen.89362*

and biological unit, a characteristic ecosystem [11].

**2.1 Oral microbiota in sulcus gingivalis**

*Prevotella loescheii* and *Prevotella denticola*.

tain balance between populations of microorganisms (**Figure 1**).

3621 phylotypes in the saliva and 6888 phylotypes in a subgingival plaque [7]. Oral cavity bacteria identified by modern sequencing methods are classified in various strains the majority of which belongs to strains (phyla) *Firmicutes*, *Fusobacteria*, *Bacteroidetes*, *Actinobacteria*, *Proteobacteria*, *Spirochaetes* and *Synergistetes*.

In addition to its principal function—intake of food and water—the mouth cavity fulfils a number of other important functions that include the primary protective function against microorganisms entering the gastrointestinal tract and various functions involving discrimination of taste, temperature and pressure [10]. In addition to properties typical of body cavities, the oral cavity possesses many differentiation features owing to which it acquires a position of separate functional

Microbiota of the oral cavity is not uniform and changes according to anatomical and physiological conditions; it is different at the orifices of salivary glands, on the surface of teeth, in sulcus gingivalis, on the tongue, at tonsils or at the buccal mucosa [12]. The growth of oral microorganisms depends on temperature, pH, oxidation-reduction potential, availability of nutrients and water, morphology of oral structures, flow of saliva and the presence of antimicrobial compounds. Each of these factors puts a selection pressure on the oral ecosystem and helps to main-

Sulcus gingivalis is one of the sites where the microorganisms from the external environment begin to act as first. The total count of cultivable bacteria in sulcus gingivalis of healthy people is relatively low and amounts to about 103–106 CFU (colony forming units) per gingival slit. Sulcus gingivalis supplies nutrients to bacteria, exhibits low redox potential and thus is colonised mostly by obligate anaerobic rods. The subgingival plaque is also dominated by *Actinomyces* and streptococci that belong among Gram-positive microorganisms. It has been assumed that microbiota of sulcus gingivalis is related to the composition of the supragingival plaque with frequent occurrence of black-pigmented rods of *Porphyromonas gingivalis*, *Porphyromonas endodontalis*, *Prevotella melaninogenica*, *Prevotella intermedia*,

*Detection of oral biofilm by means of a plaque-finder, the new dental plague is coloured red, the older one is* 

The most frequent bacterial populations in the sulcus gingivalis are the following: *Streptococcus sanguis*, *Streptococcus mitis*, *Staphylococcus epidermidis*, *Micrococcus* spp., *Mycoplasma* spp., *Trichomonas tenax*, *Entamoeba gingivalis*, *Streptococcus intermedius*, *Veillonella parvula*, *Streptococcus mobillorum*, *Streptococcus constellatus*, *Peptostreptococcus micros*, *Lactobacillus casei*, *Lactobacillus acidophilus*, *Eubacterium* 

*Oral Microbiota from the Stomatology Perspective DOI: http://dx.doi.org/10.5772/intechopen.89362*

*Bacterial Biofilms*

on conventional isolation of bacteria by cultivation, their morphology and identification by means of their biochemical properties. These methods do not suffice to ensure concise characterisation and quantification of microbiota, are time demanding, provide results not earlier than after 48 hours and involve only cultivable bacteria. High percentage of bacteria is cultivated only with difficulties due to unknown requirements on their growth [2]. Currently, a number of genetic techniques intended for quantification, identification and characterisation of bacterial communities are available. The study of the external influence on oral cavity microbiocenosis is inevitable due to high incidence and prevalence of dental caries or periodontopathies, despite the current widespread use of oral hygiene preparations [3]. Today's market offers a multitude of such preparations, and also, alternative approaches for the improvement of oral health are available. Scientific studies presented interesting knowledge about beneficial bacteria capable of inhibiting the growth of pathogenic bacteria by their bioactive products. This concerns, for example, the proof of the suppression of oral pathogens by *Streptococcus salivarius* K12 probiotic bacteria, or their bioactive compounds can serve as a basis for the development of new strategies

Immediately after birth, the sterile mouth cavity of the newborn individual mediates the contact between the internal and external environments and, at this time, also its colonisation by microorganisms commences. After several days, the microbiota characteristic of the oral cavity becomes stabilised [5]. In the process of colonisation of the mouth cavity of newborns, streptococci are acquired the first. Over time, the diversity of populating microorganisms grows until the individual acquires certain microbiota the stability of which depends on compensation mechanisms ensuring suitable conditions in the mouth cavity. Mucosa and teeth in the oral cavity come into constant contact with the exogenous microbiota, and the health state of dentition is also affected by proportions of individual groups of microorganisms. Some factors, for example unsuitable diet, can irreversibly affect the homeostasis of the oral ecosystem and subsequently lead to propagation of

Although the oral microbiota contains bacteria, fungi, viruses and archaea, research has focused mostly on oral bacterial populations present in the highest numbers [7]. Fungi as one of the components of the oral microbiota were identified by pyrosequencing with focus on RNA, which exhibits high species variability. Peterson et al. [8] reported that the number of fungal species in the oral microbiota

Molecular microbiology techniques based on 16S rRNA allowed scientists to describe more than 700 bacterial species present in the oral cavity of humans. More than 50% of bacterial species were not cultivated and thus their role in the oral microbial ecology has not been explained. It was assessed that approximately 1000 bacterial species are capable of stable existence in the mouth of humans, while each man can harbour 50–200 species of this diverse spectrum [9]. Many species are found temporarily in the saliva or as a part of biofilms formed on teeth or mucosa. Analysis of biodiversity in the mouth cavity showed that the number of oral phylotypes is considerably undervalued. Quantification of oral microbiota of humans was performed by metagenomics of unique phylotypes using pyrosequencing 454 and sequencing by Ilumina technology. This quantification method confirmed 668 bacterial phylotypes in microbiota of one plaque, which is considerably more than the numbers published in the previous studies. Similar sequencing technique detected

contributing to prevention and treatment of oral diseases [4].

**2. Oral cavity microbiome**

pathological changes in the oral cavity [6].

ranges from 9 to 23.

**280**

3621 phylotypes in the saliva and 6888 phylotypes in a subgingival plaque [7]. Oral cavity bacteria identified by modern sequencing methods are classified in various strains the majority of which belongs to strains (phyla) *Firmicutes*, *Fusobacteria*, *Bacteroidetes*, *Actinobacteria*, *Proteobacteria*, *Spirochaetes* and *Synergistetes*.

In addition to its principal function—intake of food and water—the mouth cavity fulfils a number of other important functions that include the primary protective function against microorganisms entering the gastrointestinal tract and various functions involving discrimination of taste, temperature and pressure [10]. In addition to properties typical of body cavities, the oral cavity possesses many differentiation features owing to which it acquires a position of separate functional and biological unit, a characteristic ecosystem [11].

Microbiota of the oral cavity is not uniform and changes according to anatomical and physiological conditions; it is different at the orifices of salivary glands, on the surface of teeth, in sulcus gingivalis, on the tongue, at tonsils or at the buccal mucosa [12]. The growth of oral microorganisms depends on temperature, pH, oxidation-reduction potential, availability of nutrients and water, morphology of oral structures, flow of saliva and the presence of antimicrobial compounds. Each of these factors puts a selection pressure on the oral ecosystem and helps to maintain balance between populations of microorganisms (**Figure 1**).

#### **Figure 1.**

*Detection of oral biofilm by means of a plaque-finder, the new dental plague is coloured red, the older one is coloured blue.*

### **2.1 Oral microbiota in sulcus gingivalis**

Sulcus gingivalis is one of the sites where the microorganisms from the external environment begin to act as first. The total count of cultivable bacteria in sulcus gingivalis of healthy people is relatively low and amounts to about 103–106 CFU (colony forming units) per gingival slit. Sulcus gingivalis supplies nutrients to bacteria, exhibits low redox potential and thus is colonised mostly by obligate anaerobic rods. The subgingival plaque is also dominated by *Actinomyces* and streptococci that belong among Gram-positive microorganisms. It has been assumed that microbiota of sulcus gingivalis is related to the composition of the supragingival plaque with frequent occurrence of black-pigmented rods of *Porphyromonas gingivalis*, *Porphyromonas endodontalis*, *Prevotella melaninogenica*, *Prevotella intermedia*, *Prevotella loescheii* and *Prevotella denticola*.

The most frequent bacterial populations in the sulcus gingivalis are the following: *Streptococcus sanguis*, *Streptococcus mitis*, *Staphylococcus epidermidis*, *Micrococcus* spp., *Mycoplasma* spp., *Trichomonas tenax*, *Entamoeba gingivalis*, *Streptococcus intermedius*, *Veillonella parvula*, *Streptococcus mobillorum*, *Streptococcus constellatus*, *Peptostreptococcus micros*, *Lactobacillus casei*, *Lactobacillus acidophilus*, *Eubacterium* 

*lentum*, *Propionibacterium acnes*, *Catonella* spp., *Johnsonella* spp., *Rothia dentocariosa*, *Actinomyces viscosus*, *Actinomyces odontolyticus*, *Actinomyces naeslundii*, *Capnocytophaga gingivalis*, *Capnocytophaga ochracea*, *Prevotella oralis*, *Prevotella denticola*, *Bacteroides melaninogenicus*, *Fusobacterium nucleatum*, *Eikenella corrodens*, *Wolinella* spp., *Campylobacter sputorum*, *Selenomonas sputigena*, *Treponema* spp., and *Leptotrichia* spp*., Granulicatella* spp. [13]. Of the more noteworthy representatives, one should mention parasitic protozoa *Entamoeba gingivalis* and *Trichomonas tenax* [14].
