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Oral microbiology is the study of the
microorganism
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
s (microbiota) of the oral cavity and their interactions between oral microorganisms or with the host. The environment present in the human mouth is suited to the growth of characteristic microorganisms found there. It provides a source of water and nutrients, as well as a moderate temperature.
Resident microbes of the mouth adhere to the teeth and gums to resist mechanical flushing from the mouth to stomach where acid-sensitive microbes are destroyed by
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
.
Anaerobic bacteria in the oral cavity include: ''
Actinomyces
''Actinomyces'' is a genus of the Actinomycetia class of bacteria. They all are gram-positive. ''Actinomyces'' species are facultatively anaerobic and they grow best under anaerobic conditions. ''Actinomyces'' species may form endospores, an ...
'', ''
Arachnia'' (''
Propionibacterium propionicus''), ''
Bacteroides
''Bacteroides'' is a genus of Gram-negative, obligate anaerobic bacteria. ''Bacteroides'' species are non endospore-forming bacilli, and may be either motile or nonmotile, depending on the species. The DNA base composition is 40–48% GC. Unusu ...
'', ''
Bifidobacterium
''Bifidobacterium'' is a genus of gram-positive, nonmotile, often branched anaerobic bacteria. They are ubiquitous inhabitants of the gastrointestinal tract though strains have been isolated from the vagina and mouth ('' B. dentium'') of mammal ...
'', ''
Eubacterium
''Eubacterium'' is a genus of Gram-positive bacteria in the family Eubacteriaceae. These bacteria are characterised by a rigid cell wall. They may either be motile or nonmotile. If motile, they have a flagellum
A flagellum (; ) is a hair ...
'', ''
Fusobacterium
''Fusobacterium'' is a genus of anaerobic, Gram-negative, non-sporeforming bacteria belonging to Gracilicutes. Individual cells are slender, rod-shaped bacilli with pointed ends.
Strains of ''Fusobacterium'' cause several human diseases, includin ...
'', ''
Lactobacillus
''Lactobacillus'' is a genus of Gram-positive, aerotolerant anaerobes or microaerophilic, rod-shaped, non-spore-forming bacteria. Until 2020, the genus ''Lactobacillus'' comprised over 260 phylogenetically, ecologically, and metabolically diver ...
'', ''
Leptotrichia'', ''
Peptococcus
''Peptococcus'' is a Gram-positive bacterium genus in the family Peptococcaceae.
Species in the genus are part of the human microbiome, especially in the bacteria that form the gut flora. They are part of the flora of the mouth, upper respirator ...
'', ''
Peptostreptococcus
''Peptostreptococcus'' is a genus of anaerobic, Gram-positive, non-spore forming bacteria. The cells are small, spherical
A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is t ...
'', ''
Propionibacterium
''Propionibacterium'' is a gram-positive, anaerobic, rod-shaped genus of bacteria named for their unique metabolism: They are able to synthesize propionic acid by using unusual transcarboxylase enzymes.
Its members are primarily facultative pa ...
'', ''
Selenomonas
Members of the genus ''Selenomonas'' (motile crescent-shaped bacteria in general) are referred to trivially as selenomonads. The genus ''Selenomonas'' constitutes a group of motile crescent-shaped bacteria and includes species living in the gast ...
'', ''
Treponema
''Treponema'' is a genus of spiral-shaped bacteria. The major treponeme species of human pathogens is ''Treponema pallidum'', whose subspecies are responsible for diseases such as syphilis, bejel, and yaws. ''Treponema carateum'' is the cause o ...
'', and ''
Veillonella
''Veillonella'' are Gram-negative bacteria (Gram stain pink) anaerobic cocci, unlike most Bacillota, which are Gram-positive bacteria. This bacterium is well known for its lactate fermenting abilities. It is a normal bacterium in the intestine ...
''.
Genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
of fungi that are frequently found in the mouth include ''
Candida'', ''
Cladosporium
''Cladosporium'' is a genus of fungi including some of the most common indoor and outdoor molds. Species produce olive-green to brown or black colonies, and have dark-pigmented conidia that are formed in simple or branching chains. Many species ...
'', ''
Aspergillus
' () is a genus consisting of several hundred mold species found in various climates worldwide.
''Aspergillus'' was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Miche ...
'', ''
Fusarium
''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil mi ...
'', ''
Glomus'', ''
Alternaria
''Alternaria'' is a genus of Deuteromycetes fungi. All species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma. They ...
'', ''
Penicillium
''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production.
Some members of the genus produce pe ...
'', and ''
Cryptococcus
''Cryptococcus'' is a genus of fungi in the family Cryptococcaceae that includes both yeasts and filamentous species. The filamentous, sexual forms or teleomorphs were formerly classified in the genus ''Filobasidiella'', while ''Cryptococcus'' ...
'', among others.
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
accumulate on both the hard and soft oral tissues in
biofilm
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...
s. Bacterial
adhesion
Adhesion is the tendency of dissimilar particles or surfaces to cling to one another ( cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another).
The forces that cause adhesion and cohesion can be ...
is particularly important for oral bacteria.
Oral bacteria have evolved mechanisms to sense their environment and evade or modify the host. Bacteria occupy the ecological niche provided by both the
tooth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...
surface and mucosal
epithelium
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellul ...
.
Factors of note that have been found to affect the microbial colonization of the oral cavity include the pH, oxygen concentration and availability at specific oral surfaces, mechanical forces acting upon oral surfaces, salivary and fluid flow through the oral cavity, and age.
However, a highly efficient innate host defense system constantly monitors the bacterial colonization and prevents bacterial invasion of local tissues. A dynamic equilibrium exists between
dental plaque
Dental plaque is a biofilm of microorganisms (mostly bacteria, but also fungi) that grows on surfaces within the mouth. It is a sticky colorless deposit at first, but when it forms tartar, it is often brown or pale yellow. It is commonly found bet ...
bacteria and the innate host defense system.
Of particular interest is the role of oral microorganisms in the two major dental diseases:
dental caries
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
and
periodontal disease
Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main caus ...
.
Additionally, research has correlated poor oral heath and the resulting ability of the oral microbiota to invade the body to affect cardiac health as well as cognitive function.
Oral microflora
The oral microbiome, mainly comprising bacteria which have developed resistance to the human immune system, has been known to impact the host for its own benefit, as seen with
dental cavities
Dental may refer to:
* Dental consonant, in phonetics
* Dental Records, an independent UK record label
* Dentistry, oral medicine
* Teeth
See also
*
* Dental care (disambiguation)
* Dentist (disambiguation)
* Tooth (disambiguation)
A tooth (pl ...
. The environment present in the human mouth allows the growth of characteristic microorganisms found there. It provides a source of water and nutrients, as well as a moderate temperature.
Resident microbes of the mouth adhere to the teeth and gums to resist mechanical flushing from the mouth to stomach where acid-sensitive microbes are destroyed by hydrochloric acid.
Anaerobic bacteria in the oral cavity include: ''
Actinomyces
''Actinomyces'' is a genus of the Actinomycetia class of bacteria. They all are gram-positive. ''Actinomyces'' species are facultatively anaerobic and they grow best under anaerobic conditions. ''Actinomyces'' species may form endospores, an ...
'', ''
Arachnia'', ''
Bacteroides
''Bacteroides'' is a genus of Gram-negative, obligate anaerobic bacteria. ''Bacteroides'' species are non endospore-forming bacilli, and may be either motile or nonmotile, depending on the species. The DNA base composition is 40–48% GC. Unusu ...
'', ''
Bifidobacterium
''Bifidobacterium'' is a genus of gram-positive, nonmotile, often branched anaerobic bacteria. They are ubiquitous inhabitants of the gastrointestinal tract though strains have been isolated from the vagina and mouth ('' B. dentium'') of mammal ...
'', ''
Eubacterium
''Eubacterium'' is a genus of Gram-positive bacteria in the family Eubacteriaceae. These bacteria are characterised by a rigid cell wall. They may either be motile or nonmotile. If motile, they have a flagellum
A flagellum (; ) is a hair ...
'', ''
Fusobacterium
''Fusobacterium'' is a genus of anaerobic, Gram-negative, non-sporeforming bacteria belonging to Gracilicutes. Individual cells are slender, rod-shaped bacilli with pointed ends.
Strains of ''Fusobacterium'' cause several human diseases, includin ...
'', ''
Lactobacillus
''Lactobacillus'' is a genus of Gram-positive, aerotolerant anaerobes or microaerophilic, rod-shaped, non-spore-forming bacteria. Until 2020, the genus ''Lactobacillus'' comprised over 260 phylogenetically, ecologically, and metabolically diver ...
'', ''
Leptotrichia'', ''
Peptococcus'', ''
Peptostreptococcus
''Peptostreptococcus'' is a genus of anaerobic, Gram-positive, non-spore forming bacteria. The cells are small, spherical
A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is t ...
'', ''
Propionibacterium
''Propionibacterium'' is a gram-positive, anaerobic, rod-shaped genus of bacteria named for their unique metabolism: They are able to synthesize propionic acid by using unusual transcarboxylase enzymes.
Its members are primarily facultative pa ...
'', ''
Selenomonas
Members of the genus ''Selenomonas'' (motile crescent-shaped bacteria in general) are referred to trivially as selenomonads. The genus ''Selenomonas'' constitutes a group of motile crescent-shaped bacteria and includes species living in the gast ...
'', ''
Treponema
''Treponema'' is a genus of spiral-shaped bacteria. The major treponeme species of human pathogens is ''Treponema pallidum'', whose subspecies are responsible for diseases such as syphilis, bejel, and yaws. ''Treponema carateum'' is the cause o ...
'', and ''
Veillonella
''Veillonella'' are Gram-negative bacteria (Gram stain pink) anaerobic cocci, unlike most Bacillota, which are Gram-positive bacteria. This bacterium is well known for its lactate fermenting abilities. It is a normal bacterium in the intestine ...
''.
In addition, there are also a number of fungi found in the oral cavity, including: Candida,
Cladosporium
''Cladosporium'' is a genus of fungi including some of the most common indoor and outdoor molds. Species produce olive-green to brown or black colonies, and have dark-pigmented conidia that are formed in simple or branching chains. Many species ...
,
Aspergillus
' () is a genus consisting of several hundred mold species found in various climates worldwide.
''Aspergillus'' was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Miche ...
,
Fusarium
''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil mi ...
, Glomus,
Alternaria
''Alternaria'' is a genus of Deuteromycetes fungi. All species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma. They ...
,
Penicillium
''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production.
Some members of the genus produce pe ...
, and
Cryptococcus
''Cryptococcus'' is a genus of fungi in the family Cryptococcaceae that includes both yeasts and filamentous species. The filamentous, sexual forms or teleomorphs were formerly classified in the genus ''Filobasidiella'', while ''Cryptococcus'' ...
. The oral cavity of a new-born baby does not contain bacteria but rapidly becomes colonized with bacteria such as ''
Streptococcus salivarius
''Streptococcus salivarius'' is a species of spherical, gram-positive, facultative anaerobic lactic acid bacteria that is both catalase and oxidase negative. ''S. salivarius'' colonizes (usually in chains) the oral cavity and upper respiratory ...
''. With the appearance of the teeth during the first year colonization by ''
Streptococcus mutans
''Streptococcus mutans'' is a facultatively anaerobic, gram-positive coccus (round bacterium) commonly found in the human oral cavity and is a significant contributor to tooth decay.
It is part of the " streptococci" (plural, non-italic lowercase ...
'' and ''
Streptococcus sanguinis
''Streptococcus sanguinis'', formerly known as ''Streptococcus sanguis'', is a Gram-positive facultative anaerobic coccus species of bacteria and a member of the Viridans Streptococcus group. ''S. sanguinis'' is a normal inhabitant of the healt ...
'' occurs as these organisms colonise the dental surface and gingiva. Other strains of streptococci adhere strongly to the gums and cheeks but not to the teeth. The
gingival crevice
The gingival sulcus is an area of potential space between a tooth and the surrounding gingival tissue and is lined by sulcular epithelium. The depth of the sulcus (Latin for ''groove'') is bounded by two entities: apically by the gingival fi ...
area (supporting structures of the teeth) provides a habitat for a variety of anaerobic species. Bacteroides and
spirochetes
A spirochaete () or spirochete is a member of the phylum Spirochaetota (), (synonym Spirochaetes) which contains distinctive diderm (double-membrane) gram-negative bacteria, most of which have long, helically coiled (corkscrew-shaped or ...
colonize the mouth around puberty.
Of particular interest is the role of oral microorganisms in the two major dental diseases:
dental caries
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
and
periodontal disease
Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main caus ...
.
Ecological sites for oral microbiota
As a diverse environment, a variety of organisms are able to inhabit unique ecological niches present in the oral cavity including the teeth, gingiva, tongue, cheeks, and palates.
Dental plaque
The dental plaque is made up of the microbial community that is adhered to the tooth surface; this plaque is also recognized as a biofilm. While it is said that this plaque is adhered to the tooth surface, the microbial community of the plaque is not directly in contact with the enamel of the tooth. Instead, bacteria with the ability to form attachments to the acquired pellicle, which contains certain salivary proteins, on the surface of the teeth, begin the establishment of the biofilm. yes. Upon dental plaque maturation, in which the microbial community grows and diversifies, the plaque is covered in an interbacterial matrix.
Dental calculus
The calculus of the oral cavity is the result of mineralization of and around dead microorganisms; this calculus can then be colonized by living bacteria. Dental calculus can be present on supragingival and subgingival surfaces.
Oral mucosa
The mucosa of the oral cavity provides a unique ecological site for microbiota to inhabit. Unlike the teeth, the mucosa of the oral cavity is frequently shedding and thus its microbial inhabitants are both kept at lower relative abundance than those of the teeth but also must be able to overcome the obstacle of the shedding epithelia.
Tongue
Unlike other mucosal surfaces of the oral cavity, the nature of the top surface of the tongue, due in part to the presence of numerous papillae, provides a unique ecological niche for its microbial inhabits. One important characteristic of this habitat is that the spaces between the papillae tend to not receive much, if any, oxygenated saliva, which creates an environment suitable for microaerophilic and obligate anaerobic microbiota.
Acquisition of oral microbiota
Acquisition of the oral microbiota heavily depends on the route of delivery as an infant - vaginal versus caesarian; upon comparing infants three months after birth, infants born vaginally were reported to have higher oral taxonomic diversity than their cesarean born counterparts.
Further acquisition is determined by diet, developmental accomplishments, general lifestyle habits, hygiene, and the use of antibiotics.
Breastfed infants are noted to have higher oral lactobacilli colonization than their formula-fed counterparts.
Diversity of the oral microbiome is also shown to flourish upon the eruption of primary teeth and later adult teeth, as new ecological niches are introduced to the oral cavity.
Factors of microbial colonization
Saliva plays a considerable role in influencing the oral microbiome. More than 800 species of bacteria colonize oral mucous, 1,300 species are found in the gingival crevice, and nearly 1,000 species comprise dental plaque. The mouth is a rich environment for hundreds of species of bacteria since saliva is mostly water and plenty of nutrients pass through the mouth each day. When kissing, it takes only 10 seconds for no less than 80 million bacteria to be exchanged by the passing of saliva. However, the effect is transitory, as each individual quickly returns to their own equilibrium.
Thanks to progress in molecular biology techniques, scientific understanding of oral ecology is improving. Oral ecology is being more comprehensively mapped, including the tongue, the teeth, the gums, salivary glands, etc. which are home to these communities of different microorganisms.
The host's immune system controls the bacterial colonization of the mouth and prevents local infection of tissues. A dynamic equilibrium exists notably between the bacteria of dental plaque and the host's immune system, enabling the plaque to stay behind in the mouth when other biofilms are washed away.
In equilibrium, the bacterial biofilm produced by the fermentation of sugar in the mouth is quickly swept away by the saliva, except for dental plaque. In cases of imbalance in the equilibrium, oral microorganisms grow out of control and cause oral diseases such as tooth decay and periodontal disease. Several studies have also linked poor oral hygiene to infection by pathogenic bacteria.
Role in health
There are many factors of oral health which need to be preserved in order to prevent pathogenesis of the oral microbiome or diseases of the mouth.
Dental plaque
Dental plaque is a biofilm of microorganisms (mostly bacteria, but also fungi) that grows on surfaces within the mouth. It is a sticky colorless deposit at first, but when it forms tartar, it is often brown or pale yellow. It is commonly found bet ...
is the material that adheres to the teeth and consists of bacterial cells (mainly ''S. mutans'' and ''S. sanguis''), salivary polymers and bacterial extracellular products. Plaque is a biofilm on the surfaces of the teeth. This accumulation of microorganisms subject the teeth and gingival tissues to high concentrations of bacterial metabolites which results in dental disease. If not taken care of, via brushing or flossing, the plaque can turn into
tartar (its hardened form) and lead to
gingivitis
Gingivitis is a non-destructive disease that causes inflammation of the gums. The most common form of gingivitis, and the most common form of periodontal disease overall, is in response to bacterial biofilms (also called plaque) that is attached ...
or
periodontal disease
Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main caus ...
. In the case of
dental cavities
Dental may refer to:
* Dental consonant, in phonetics
* Dental Records, an independent UK record label
* Dentistry, oral medicine
* Teeth
See also
*
* Dental care (disambiguation)
* Dentist (disambiguation)
* Tooth (disambiguation)
A tooth (pl ...
, proteins involved in colonization of teeth by ''
Streptococcus mutans
''Streptococcus mutans'' is a facultatively anaerobic, gram-positive coccus (round bacterium) commonly found in the human oral cavity and is a significant contributor to tooth decay.
It is part of the " streptococci" (plural, non-italic lowercase ...
'' can produce antibodies that inhibit the
cariogenic process which can be used to create
vaccine
A vaccine is a biological Dosage form, preparation that provides active acquired immunity to a particular infectious disease, infectious or cancer, malignant disease. The safety and effectiveness of vaccines has been widely studied and verifie ...
s.
Bacteria species typically associated with the oral microbiota have been found to be present in women with
bacterial vaginosis
Bacterial vaginosis (BV) is a disease of the vagina caused by excessive growth of bacteria. Common symptoms include increased vaginal discharge that often smells like fish. The discharge is usually white or gray in color. Burning with urination ...
.
Genera of fungi that are frequently found in the mouth include ''
Candida'', ''
Cladosporium
''Cladosporium'' is a genus of fungi including some of the most common indoor and outdoor molds. Species produce olive-green to brown or black colonies, and have dark-pigmented conidia that are formed in simple or branching chains. Many species ...
'', ''
Aspergillus
' () is a genus consisting of several hundred mold species found in various climates worldwide.
''Aspergillus'' was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Miche ...
'', ''
Fusarium
''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil mi ...
'', ''
Glomus'', ''
Alternaria
''Alternaria'' is a genus of Deuteromycetes fungi. All species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma. They ...
'', ''
Penicillium
''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production.
Some members of the genus produce pe ...
'', and ''
Cryptococcus
''Cryptococcus'' is a genus of fungi in the family Cryptococcaceae that includes both yeasts and filamentous species. The filamentous, sexual forms or teleomorphs were formerly classified in the genus ''Filobasidiella'', while ''Cryptococcus'' ...
'', among others.
Additionally, research has correlated poor oral heath and the resulting ability of the oral microbiota to invade the body to affect cardiac health as well as cognitive function.
High levels of circulating
antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
to oral pathogens ''
Campylobacter rectus
''Campylobacter rectus'' is a species of '' Campylobacter''. It is implicated as a pathogen in chronic periodontitis, which can induce bone loss. This motile bacillus is a Gram negative, facultative anaerobe. ''C. rectus'' is associated with hype ...
'', ''
Veillonella parvula
''Veillonella parvula'' is a strictly anaerobic, Gram-negative, coccus-shaped bacterium in the genus ''Veillonella''. It is a normal part of the oral flora but can be associated with diseases such as periodontitis and dental caries as well as var ...
'' and ''
Prevotella melaninogenica
''Prevotella melaninogenica'' is a species of bacterium in the normal microbiota of the upper respiratory tract. It is an important human pathogen in various anaerobic infections, often mixed with other aerobic and anaerobic bacteria. ''P. melan ...
'' are associated with
hypertension
Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...
in human.
Importance of dental hygiene
Maintaining a balanced oral microflora is important for total wellness. The best way to maintain this environment is with proper
oral hygiene
Oral hygiene is the practice of keeping one's mouth clean and free of disease and other problems (e.g. bad breath) by regular brushing of the teeth (dental hygiene) and cleaning between the teeth. It is important that oral hygiene be carried out ...
. Insufficient brushing and flossing can lead to
gum and
tooth disease, and eventually
tooth loss Tooth loss is a process in which one or more teeth come loose and fall out. Tooth loss is normal for deciduous teeth (baby teeth), when they are replaced by a person's adult teeth. Otherwise, losing teeth is undesirable and is the result of inju ...
.
In addition, poor dental hygiene has been linked to conditions such as
osteoporosis
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone fragility, and consequent increase in fracture risk. It is the most common reason for a broken bone ...
,
diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
and
cardiovascular disease
Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, h ...
s.
Some diseases and medications are known to limit salivary flow, making it easier for bacteria to overgrow in the mouth without being washed away. To prevent any possible side effects from poor oral hygiene, it is important to brush and floss every day, schedule regular cleanings, eat a healthy diet and use a recently replaced toothbrush.
Issues and areas of research
The oral environment (temperature, humidity, pH, nutrients, etc.) impacts the selection of adapted (and sometimes pathogenic) populations of microorganisms.
[Linda Sherwood, Joanne Willey and Christopher Woolverton, , New York, McGraw Hill, 2013, 9th ed., p. 713–721] For a young person or an adult in good health and with a healthy diet, the microbes living in the mouth adhere to mucous, teeth and gums to resist removal by saliva. Eventually, they are mostly washed away and destroyed during their trip through the stomach.
Salivary flow and oral conditions vary person-to-person, and also relative to the time of day and whether or not an individual sleeps with their mouth open. From youth to old age, the entire mouth interacts with and affects the oral microbiome. Via the
larynx
The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about ...
, numerous bacteria can travel through the respiratory tract to the
lung
The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
s. There,
mucous
Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...
is charged with their removal. Pathogenic oral microflora have been linked to the production of factors which favor autoimmune diseases such as
psoriasis
Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complete ...
and
arthritis
Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In som ...
, as well as
cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
s of the
colon, lungs and
breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues.
In females, it serves as the mammary gland, which produces and secret ...
s.
[↑ Fleming, C. J. (2016). Microbiota activated CD103+ DCS stemming from oral microbiota adaptation specifically drive γδT17 proliferation and activation.]
Intercellular communication
Most of the bacterial species found in the mouth belong to microbial communities, called
biofilm
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...
s, a feature of which is inter-bacterial communication. Cell–cell contact is mediated by specific protein
adhesins and often, as in the case of inter-species aggregation, by complementary
polysaccharide
Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wa ...
receptors. Another method of communication involves cell–cell signalling molecules, which are of two classes: those used for intra-species and those used for inter-species signalling. An example of intra-species communication is
quorum sensing
In biology, quorum sensing or quorum signalling (QS) is the ability to detect and respond to cell population density by gene regulation. As one example, QS enables bacteria to restrict the expression of specific genes to the high cell densities at ...
. Oral bacteria have been shown to produce small peptides, such as
competence stimulating peptides, which can help promote single-species biofilm formation. A common form of inter-species signalling is mediated by
4, 5-dihydroxy-2, 3-pentanedione (DPD), also known as
autoinducer-2
Autoinducer-2 (AI-2), a furanosyl borate ester, borate diester or tetrahydroxy furan (species dependent), is a member of a family of signaling molecules used in quorum sensing. AI-2 is one of only a few known biomolecules incorporating boron. Firs ...
(Al-2).
See also
*
Biofilms
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular po ...
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Dental plaque
Dental plaque is a biofilm of microorganisms (mostly bacteria, but also fungi) that grows on surfaces within the mouth. It is a sticky colorless deposit at first, but when it forms tartar, it is often brown or pale yellow. It is commonly found bet ...
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Environmental microbiology
A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
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Human microbiota
This article lists some of the species recognized as belonging to the human microbiome.
Whole-body distributed
*''Acinetobacter calcoaceticus''
*'' Burkholderia cepacia''
*''Pseudomonas pseudoalcaligenes''
*''Peptostreptococcus spp''
Natur ...
*
Human Microbiome Project
The Human Microbiome Project (HMP) was a United States National Institutes of Health (NIH) research initiative to improve understanding of the microbiota involved in human health and disease. Launched in 2007, the first phase (HMP1) focused on i ...
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Microbiology
Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, prot ...
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Theodor Rosebury Theodor Rosebury (London, 10 August 1904—Conway, Massachusetts, 25 November 1976) was a British-born American bacteriologist and author. He has been called the “pre-eminent oral microbiologist of his era” and the “Grandfather of Modern Oral ...
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List of bacterial vaginosis microbiota
Bacterial vaginosis is caused by an imbalance of the naturally occurring bacteria in the vagina. The normally predominant species of ''Lactobacilli'' are markedly reduced. This is the list of organisms that are found in the vagina that are assoc ...
References
External links
Human Oral Microbiome Database (HOMD)
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Microbiology
Dentistry branches
Microbiomes