Periodontal Microbiology

Where is the Streptococcus Mitis group found?

dental plaque, tongue and cheek

Where is the Streptococcus Salivarius group found?

dorsum of the tongue and saliva

What are the stages of plaque formation?

1. Pellicle formation - thin layer of salivary glycoproteins 2. Reversible attachment - bacteria attach to the pellicle 3. Irreversible attachment - bacterial adhesins and receptors (help with anchoring of future generations) 4. Biofilm maturation and detachment - horizontal growth

What are the 6 major ecosystems in the oral cavity?

1. Supragingival, hard surfaces 2. Subgingival 3. Buccal, palatal epithelium, epithelium of floor of the mouth 4. Dorsum of the tongue 5. Tonsils 6. Saliva

Describe general biofilm development

1. Uncolonized surface 2. Deposition of conditioning layer - Initial attachment 3. Early colonizing bacteria - Irreversible attachment 4. Phenotypic changes - maturation and dispersion

What are the 3 types of periodontal pockets?

A. Gingival pocket B. Suprabony pocket C. Infrabony pocket

Which of the following microorganisms has an important role in biofilm formation: A. Streptococcus mutans B. Porphyromonas gingivalis C. Prevotella intermedia D. Spirochetes

A. Streptococcus mutans

This microorganism is a gram-negative bacteria that colonizes oral mucosa and some of their virulent factor are LPS and leukotoxin: C. Actinobacillus actinomycetemcomitans B. Bacteroides forsythus D. Bifidobacterium catenulatum A. Porphyromonas gingivalis

Actinobacillus actinomycetemcomitans

Describe Spirochetes

Anaerobic, gram -, helical shaped, motile, common in periodontal pockets

What liquid bathes the supragingival tooth surfaces

Bathes in saliva

As biofilm thickens it: A. Becomes more anaerobic B. It has an equilibrium between Gram positive and Gram negative C. Becomes more aerobic D. Increases in Gram positive population

Becomes more anaerobic

All the following statements are correct about calculus EXCEPT: A. It is a form of hardened dental plaque C. It is a product of bacterial metabolites D. Electro microscopic images are like corn-cob arrangements B. It is associated with bad breath, receding gums and gingivitis

C. It is a product of bacterial metabolites

What are the virulence factors of P. Gingivalis?

Collagenase - destroy tissue Hemolysins Hyaluronidase and phospholipase Fimbriae - adhesion Degradative enzymes Gingipain - trigger cell apoptosis

What are the roles of beneficial species in the mouth? (5)

Passively occupy niches (keeping pathogenic ones out) limits pathogens ability to adhere affects vitality or growth of pathogens affects the ability of pathogens to produce virulence factors degrade virulence factors

What are the virulence factors of spirochetes

Endotoxin ability to penetrate tissue inhibits lymphocyte activation blocks fusion of phagosomes destroys IgG's

What are the 3 extracellular polymeric substances (EPS) of biofilms?

Extracellular DNA Proteins Polysaccharides

All of the following virulent factor about P. ginvivalis are true, EXCEPT: A. Gingipains D. Fimbrae C. Hyaluronidase B. Produces superantigens (SAgs)

Produces superantigens (SAgs)

Describe Dental Plaque

Resilient clear/ yellow substance Primarily composed of bacteria Considered to be a biofilm

All of the following microorganism are associated with periodontal health EXCEPT: C. Veillonella parvulla D. C. ochracea B. S. sanguis or S. sanguinis A. Firmicutes species

Firmicutes species

Which of the following bacteria and/or species are predominant in the supragingival plaque: C. S. mutans B. Eubacterium species A. S. aureus D. Candida albicans

S. mutans

What are some examples of good bacteria in the mouth?

S. sanguis, Veillonella parvula, C. ochracea

Where is the Streptococcus Mutans group found?

Found on the tooth surface

What is the primary cause of gingival inflammation

bacterial plaque

What liquid bathes the subgingival tooth surfaces and epithelium lining of gingival crevice?

Gingival Crevicular Fluid (GCF)

Where is the Streptococcus Anginosus group found?

Gingival crevice

Describe oral microbial shift from healthy to pathogenic

Gram (+) to Gram (-) Cocci => Rods => spirochetes nonmotile to motile facultative anaerobes => obligate anaerobes fermenting => proteolytic

What type of bacteria predominantly cause gingivitus?

Gram (-), anaerobic, proteolytic, rod-shaped and spirochetes bacteria

When gingivitis occurs, what are some of the microbiological population changes?

Gram +: rods, and cocci decrease Gram -: rods and filaments increase Spirochetal and motile species increase

Describe prevotella intermedia

Gram -, non-motile, rods, strict anaerobes Require vitamin K associated with chronic periodontitis

Gingivitis and Periodontal disease present and increase amount of: D. Gram negative and Facultative B. Gram positive and Anaerobes A. Gram positive and Facultative C. Gram negative and Anaerobes

Gram negative and Anaerobes

Describe calculus

Hard deposit that forms by mineralization of dental plaque Generally covered by a layer of unmineralized dental plaque

What are the virulence factors of Actinobacillus actinomycetes?

adhesins - promote colonization Leukotoxin - kills neutrophils and macrophages immunosuppressive factors LPS activates alternate complement pathway collagenase- factors that destroy host tissue

What type of organism is mostly found in supragingival calculus?

Mostly Gram-positive organisms

What type of organism is mostly found on subgingival calculus?

Mostly gram-negative species

What are the 4 main streptococcus species found supragingivally?

Mutans group Salivarius group Anginosus group mitis group

What do bacteria in the mouth use to adhere to a surface?

Pili and fimbriae

Which of the following is not an ecological niche of the oral cavity? E. All of the above B. Tongue C. Skin D. Salivary ducts A. Supragingival tooth surface

Skin

What are some of the first pathogens identified in the oral cavity of newborns?

Streptococcus salivarius Streptococcus mitis

Ecologic plaque hypothesis refers to:

The amount of total microbial composition and its contribution to health and disease

True or false? Biofilm are adherent mixtures of bacteria composed of extracellular DNA, proteins and polysaccharides.

True

What are the virulence factors of prevotella intermedia?

Trypsin like protease -degrades IgG's Hemagglutinin-agglutinates RBC's Hydrogen sulfide - cytotoxic Proteases LPS

Which of the following species are predominant in the subgingival plaque: A. Veillonela species C. Roseburia species B. Mutant species D. Candida species

Veillonela species

Describe materia alba

White cheeselike accumulation lacks organized structure easily displaced with water spray soft accumulation of salivary proteins,