2: CARIOGENIC MICROORGANISMS Flashcards by Secret acc

Q

______ are microorganisms that play a key role in the development of dental caries (cavities).

A

Cariogenic bacteria

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Q

______
• They are primarily responsible for producing acids that break down tooth enamel, Dentin and Cementum. ultimately leading to tooth decay.

A

Cariogenic Bacteria

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Q

The Cariogenic Bacteria are as follows:

A

• Streptococcus mutans
• Streptococcus sanguis
• Lactobacillus species
• Actinomyces species

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Q

Characteristics of Cariogenic bacetria:

A

ACID PRODUCTION
BIOFILM FORMATION

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Q

Characteristics of Cariogenic bacetria

Acid Production, Cariogenic bacteria ferment ______ and ______, producing acidic byproducts that dissolve ______ and ______ in tooth enamel and Dentin.

A

sugars, starches, calcium, hydroxyapatite crystals

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Q

Characteristics of Cariogenic bacetria

Biofilm Formation, These bacteria form a ______, a sticky layer of bacteria and other substances that adheres to the tooth surface, creating an environment where they thrive and can more effectively damage the tooth.

A

biofilm

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Q

Essential Features of Cariogenic Bacteria:

A

Acidogenic Bacteria
Aciduric Bacteria

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Q

Essential Features of Cariogenic Bacteria

______
• Are organisms that produce acid as a byproduct of their metabolic activities, particularly through the ______ of ______ like ______.

A

Acidogenic Bacteria, fermentation, carbohydrates, sugars

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Q

Essential Features of Cariogenic Bacteria

______
• Contribute to the lowering of pH in their environment, which can lead to the demineralization of tooth enamel and promote conditions favorable for tooth decay.

A

Acidogenic Bacteria

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Q

Essential Features of Cariogenic Bacteria

______
• Many produce sticky substances (like ______) or have ______ that help them adhere to tooth surfaces and form biofilms (plaque).

A

Acidogenic Bacteria, glucans, adhesins

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Q

Essential Features of Cariogenic Bacteria

______
• It lowers the pH environment and promotes tooth caries.

A

Acidogenic Bacteria

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Q

Essential Features of Cariogenic Bacteria

______
• Are microorganisms that can survive and grow in environments with low pH.

A

Aciduric Bacteria

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Q

Essential Features of Cariogenic Bacteria

______
• Common in acidic habitats such as the human oral cavity, where they play a role in the development of dental caries (cavities).

A

Aciduric Bacteria

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Q

Essential Features of Cariogenic Bacteria

______
• Thrive in environments with high acid concentrations, often produced by the ______ of ______.

A

Aciduric Bacteria, fermentation, sugars

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Q

Essential Features of Cariogenic Bacteria

______
• Can metabolize sugars into organic acids, contributing to the demineralization of tooth enamel and the progression of dental decay.

A

Aciduric Bacteria

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Q

Essential Features of Cariogenic Bacteria

______
• A major factor in the progression of dental decay, as their ability to ______ and produce ______ in an acidic environment continuously degrades tooth enamel.

A

Aciduric Bacteria, survive, acid

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Q

Streptococcus mutans

Clinical Significance
• ______ is a major concern in dentistry, leading to pain, infection, and tooth loss.

A

Dental caries

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Q

Streptococcus mutans

Clinical Significance
• ______ play a critical role in both the ______ (enamel caries) and ______ (dentin caries) of the disease.

A

S. mutans, initiation, progression

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Q

Streptococcus mutans

Basic Characteristics:

A

• Gram-positive coccus
• Facultative anaerobe
• Forms biofilms on teeth

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Q

Streptococcus mutans

Key Characteristics:

A

• Strongly acidogenic
• Highly aciduric
• Produces extracellular polysaccharides (EPS)

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Q

Streptococcus mutans

Acid Production and Enamel Demineralization
• ______ metabolizes dietary ______ (especially ______) into ______, primarily ______.
• This acid ______ the pH at the enamel surface.

A

S. mutans, carbohydrates, sucrose, acids, lactic acid

lowers

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Q

Streptococcus mutans

Acid Production and Enamel Demineralization
• When the pH drops below the critical level (approximately ______), ______ begins.

A

5.5, enamel demineralization

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Q

Streptococcus mutans

Acid Production and Enamel Demineralization
• Clinical manifestation:
“______” - early, reversible enamel caries

A

White spot lesions

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Q

Streptococcus mutans

Acid Tolerance and Caries Progression
• ______ can ______ and produce ______ in the acidic environment it creates.
• This ______ is crucial for the progression of caries into dentin.

A

S. mutans, survive, acid

aciduricity

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Streptococcus mutans Acid Tolerance and Caries Progression • Once the enamel is compromised, ______ can penetrate the ______.

S. mutans, dentin

Streptococcus mutans Acid Tolerance and Caries Progression • ______ demineralization is more complex: - ______ of the ______ component - Degradation of the ______ by ______

Dentin Acid dissolution, mineral collagen matrix, bacterial enzymes

Streptococcus mutans The Role of Extracellular Polysaccharides (EPS) S. mutans produce EPS (______ and ______). EPS facilitates: • ______ to the tooth • ______ formation and ______ • Creates a ______, trapping ______ against the tooth surface This localized acidic environment accelerates ______.

glucans, fructans Adhesion, Biofilm, stability diffusion barrier, acid, demineralization

Streptococcus mutans Clinical Implications: Enamel Caries Early detection of ______ is important. ______ at this stage: • ______ therapy • Improved ______ • ______ modification If untreated, it progresses to ______.

white spot lesions, Reversible Fluoride oral hygiene Dietary, cavitation

Streptococcus mutans Clinical Implications: Dentin Caries • ______ require ______ treatment (______).

Dentin caries, restorative, fillings

Streptococcus mutans Clinical Implications: Dentin Caries • Complete removal of infected ______ is essential.

dentin

Streptococcus mutans Clinical Implications: Dentin Caries • Understanding the extent of ______ is vital for treatment planning.

demineralization

Streptococcus mutans Clinical Implications: Dentin Caries • ______ are still present in deep ______, even if other bacteria are more prevalent.

S. mutans, lesions

______ is a key etiological agent in both enamel and dentin caries. Its virulence factors directly contribute to the clinical manifestations of the disease.

S. mutans

In the absence of ______, other acidogenic and acidtolerant species can initiate caries.

S. mutans

______ reside in crevices and small fissures where it relies on ______—a strongly adhesive polysaccharide—that it produces to secure cells to the tooth and gum surface.

S. mutans, dextran

______ is the most abundant genus in the mouth, comprising about ______% of cells found in some individuals.

Streptococcus, 25

Streptococcus sanguinis General Characteristics • ______, previously known as ______, is typically associated with healthy plaque biofilm.

Streptococcus sanguinis, S. sanguis

Streptococcus sanguinis General Characteristics • It is a ______, ______, ______

Gram-positive, nonspore-forming, facultative anaerobe

Streptococcus sanguinis General Characteristics • ______ is a ______, aiding in the attachment of succeeding organisms, and a key player in oral biofilm development

S. sanguinis, pioneering colonizer

Streptococcus sanguinis General Characteristics • ______ is a ______ that is widely distributed in the oral cavity. It exists on tooth surfaces, oral mucosa surfaces and in human saliva

S. sanguinis, commensal bacterium

Streptococcus sanguinis General Characteristics • ______ is ______, but less acidogenic compared to more cariogenic bacteria

S. sanguinis, acidogenic

Streptococcus sanguinis Attachment of S. sanguinis to the tooth surface • ______ are involved in attachment to both animate and inanimate surfaces and in the formation of biofilms in many species of bacteria

Fimbriae

Streptococcus sanguinis Attachment of S. sanguinis to the tooth surface • ______ mediated the adhesion of S. sanguinis to ______-coated ______. Tooth surfaces are coated with a large amount of salivary proteins. ______ binding to salivary components may help S. sanguinis attach to tooth surfaces and initiate biofilm formation in the oral cavity.

Fimbriae, saliva, hydroxyapatite, Pilus

Streptococcus sanguinis Streptococcus sanguinis’s role in enamel caries formation • ______ is an ______ bacteria that can ferment ______, producing ______ that contribute to enamel demineralization,

S. sanguinis, acidogenic, carbohydrates, acids

Streptococcus sanguinis Streptococcus sanguinis’s role in enamel caries formation • S. sanguinis is less ______ than S. mutans

acidogenic

Streptococcus sanguinis Streptococcus sanguinis’s association with oral health • In numerous studies, ______ has been frequently associated with ______ health

Streptococcus sanguinis, oral

Streptococcus sanguinis Streptococcus sanguinis’s association with oral health • It has an ______ relationship with bacterial species that are caries associated and may have an ______ effect against cariogenic species.

inverse, antagonistic

Streptococcus sanguinis Streptococcus sanguinis’s association with oral health • In one study, oral colonization of infants with ______ was correlated with a significant ______ in colonization with ______ streptococci.

S. sanguinis, delay, mutans

Streptococcus sanguinis Streptococcus sanguinis’s association with oral health • ______ produced by S. sanguinis ______ the growth of S. mutans

H2O2, represses

Streptococcus sanguinis Streptococcus sanguinis’s association with oral health • In the oral ______ community, some oral bacteria produce ______ from the metabolism of ______ via the ______, which protects against caries caused by S. mutans and other aciduric bacteria.

commensal, alkali, arginine, arginine deiminase system (ADS)

Streptococcus sanguinis Streptococcus sanguinis’s association with oral health • ______ is the most prevalent species in the oral cavity that contains the ADS. It may utilize the ADS to maintain ______ and gain an advantage in competing with ______.

S. sanguinis, pH homeostasis, S. mutans

Streptococcus sanguinis Streptococcus sanguinis’s association with oral health • ______ are synthesized by ______ to suppress the growth of S. sanguinis. ______ of S. mutans is necessary for ______ production and can be inactivated by ______.

Mutacins, S. mutans, CSP, mutacins, S. sanguinis

______ • are not primary caries initiators but contribute to dentin caries progression due to their ______ and ______ nature.

Lactobacillus species, acidogenic, aciduric

______ • As fermentative organisms, they produce ______ and thrive in low ______, ______.

Lactobacillus species, lactic acid, pH, deep lesions

______ • Their acid resistance makes them dominant in later caries stages, significantly contributing to dentin demineralization.

Lactobacillus species

Lactobacilli are:

• Rod-shaped, homofermentative • More acid-resistant than other lactic acid bacteria • Capable of growing at pH as low as 4

Lactobacillus species:

• Lactobacillus acidophilus • Lactobacillus brevis • Lactobacillus delbrueckii

Lactobacillus species ______ • Classic acid-producing species

Lactobacillus acidophilus

Lactobacillus species ______ • Isolated in high numbers in advanced carious lesions

Lactobacillus acidophilus

Lactobacillus species ______ • Occasionally isolated from carious dentin, especially in advanced lesions.

Lactobacillus brevis

Lactobacillus species ______ • May support lesion progression in dentin but is less commonly found compared to dominant species.

Lactobacillus brevis

Lactobacillus species ______ • used in yogurt fermentation.

Lactobacillus delbrueckii

Lactobacillus species ______ • Sometimes detected in carious dentin; its acidogenic and aciduric traits make it a possible contributor, particularly in deep lesions.

Lactobacillus delbrueckii

______ • Gram-positive bacteria, filamentous rods

Actinomyces species

______ • facultative anaerobes

Actinomyces species

______ • form branching networks resembling fungal hyphae

Actinomyces species

______ • contribute to plaque biofilm formation

Actinomyces species

Actinomyces species • Part of normal oral ______, ______, and ______

microbial flora, gastrointestinal tract, urogenital tract

Actinomyces species • However, under certain conditions—such as poor oral hygiene, gingival recession, or shifts in microbial balance—______ can become ______ by fermenting ______ and producing ______ on exposed root surfaces

Actinomyces spp., opportunistic pathogens, carbohydrates, acid

Actinomyces species:

• Actinomyces naeslundii • Actinomyces viscosus • Actinomyces israelii

Actinomyces species ______ Role in Root Caries • Early colonizer of tooth root surface

Actinomyces naeslundii

Actinomyces species ______ Role in Root Caries • Initiate biofilm formation

Actinomyces naeslundii

Actinomyces species ______ Role in Root Caries • Produces acids that deminiralize dentin and cementum

Actinomyces naeslundii

Actinomyces species ______ Favourable condition • Gingival recession (exposed root)

Actinomyces naeslundii

Actinomyces species ______ Favourable condition • Low oxygen environment

Actinomyces naeslundii

Actinomyces species ______ Favourable condition • Frequent carbohydrate intake

Actinomyces naeslundii

Actinomyces species ______ Favourable condition • Poor oral hygiene

Actinomyces naeslundii

Actinomyces species ______ Role in Root Caries • Strong adherence to cementum and dentin

Actinomyces viscosus

Actinomyces species ______ Role in Root Caries • Ferments carbohydrates to lactic acid

Actinomyces viscosus

Actinomyces species ______ Role in Root Caries • Contributes to lesion progression

Actinomyces viscosus

Actinomyces species ______ Favourable condition • Exposed root surfaces

Actinomyces viscosus

Actinomyces species ______ Favourable condition • Plaque accumulation

Actinomyces viscosus

Actinomyces species ______ Favourable condition • Dry mouth (xerostomia)

Actinomyces viscosus

Actinomyces species ______ Favourable condition • Diet rich in fermentable sugars

Actinomyces viscosus

Actinomyces species ______ Role in Root Caries • Not a primary caries pathogen

Actinomyces israelii

Actinomyces species ______ Role in Root Caries • May be present in advanced or mixed infections

Actinomyces israelii

Actinomyces species ______ Role in Root Caries • More associated with chronic oral infections (e.g., actinomycosis)

Actinomyces israelii

Actinomyces species ______ Favourable condition • Deep periodontal pockets

Actinomyces israelii

Actinomyces species ______ Favourable condition • Poor oral hygiene over long periods

Actinomyces israelii

Actinomyces species ______ Favourable condition • Compromised immune system

Actinomyces israelii