-          Intraoral, supragingival, hard surfaces (teeth implants, restorations, and prostheses).

-          Periodontal/periimplant pocket (with its crevicular fluid, the rool cementum or implant surface, and the pocket epithelium).

-          Buccal epithelium, palatal epithelium, and epithelium of the floor of the mouth.

-          Dorsum of the tongue

-          Tonsils

Subgingival uses tissue and cellular breakdown products and carbohydrates from GCF and serum

1.      Occupying a niche that may otherwise be colonized by pathogens.

2.      Limiting pathogens ability to adhere to tissues.

3.      Adversely affecting the vitality or growth of a pathogen.

4.      By affecting the ability of a pathogen to produce virulence factors.

5.      Directly degrading virulence factors produced by a pathogen.

The bacteria associated with periodontal health are primary gram-positive facultative  species and members of the genera Streptococcus and Actinomyces (S. sanguis, S. mitis, and A. viscosus)

which bacteria are associated with gingivitis?

*The microbiota of dental plaque induced gingivitis (chronic gingivitis) consists of approximately equal proportions of gram positive (56%) and gram negative (44%) species, as well as facultative (59%) and anaerobic (41%) microorganisms.

This condition is accompanied by increases in steroid hormones in crevicular fluid and dramatic increases in the levels of P. intermedia, which uses the steroids as growth factors and flourishes.

-          Microscopic examination of plaque from sites with chronic periodontitis has consistently revealed elevated proportions of spirochetes.

-          Bacteria most often cultivated at high levels:

1.      Actinobacillus aggregabacter

2.      Tannerella forsythia

3.      Porphyromonas gingivalis

4.      Treponema denticola (spyrocyte)

5.      Prevotella intermedia

6.      E. corrodens

7.      Camphlobacter rectus

8.      Peptostreptococcus micros (gram +)

9.      Fusobacterium nucleatum

10.  Eubacterium nodatum

 recent studies show an association between PD and viruses.

EBV-1 and HCMV

When present, higher levels of perio pathogens.

Role of viruses isn't clear however, they may contribute to pathogenesis.

A. aggregatibacter is present in almost all disease sites and is 90% of the total cultivable microbiota.

• Characterized by rapid and severe attachment loss occurring in individuals during or before puberty.

• Gram negative microbiota

• Anaerobic rods

• Treatment combines mechanical debridement with a combination of systemic antibiotics.

• Because A. aggregatibacter invades the tissues, mechanical therapy my not be enough to restore health to the periodontium.

1. P. intermedia- gram - rod

2. Treponema vincentii- spirochete

Necrosis of the marginal gingival tissue and interdental papillae.

Related to stress and HIV

Malodor, pain, fever, malaise.

Can invade necrotic tissue and apparently unaffected connective tissue.

Periimplantitis

Organisms: (similar to chronic PD)

A. aggregatibacter

P. gingivalis

T. forsythia

P. micros

C. rectus

Fusobacterium

capnocytophaga

*inflammation affecting the tissues around an already osseointegrated implant.

Actinobacillus aggregatibacter

used to be known as

actinobacillus actinomycetemcomitans

• Gram negative
  
• rod

• Nonmotile

• Anaerobic

• Virulence factors

  • Lipopolysacchride (LPS) (endotoxin)
  • Leukotoxin (LT) (exotoxin)
  • Collagenase - destroys connective tissue.
  • Protease -can cleave IgA.

  • Can invade connective tissue and collagen

• present in chronic perio, localised aggressive periodontitis, and periimplantitis
  

• gram -
• rod
• nonmotile
• obligate anaerobe
• virulence factors
  • LPS
  • proteolytic enzymes (destroys immunoglobins and components of the complement system)
  • induces apoptosis
• associated with chronic perio disease and periimplantitis

• gram -
• obligate anaerobe
• non motile
• virulence factors
  • fimbrae help with adhesion
  • capsule defends against phagocytosis
  • LPS
  • proteases- destroys immunoglobulins and complement factors
  • hemolysin- (exotoxin that can lyse RBCs)
  • collagenase
  • inhibits PMN chemotaxis- cant migrate across epithelial barrier
  • affects cytokine production
  • can invade soft tissue
• associated with chronic perio, LAP and periimplantitis

• gram -
• rod
• nonmotile
• virulence factor
  • LPS
• P. intermedia is associated with chronic perio disease, NUG/NUP, gingivitis and pregnancy gingivitis
• the prevotella are less virulent than porphyromonas gingivalis

campylobacter rectus

• gram -
• rod
• anaerobe
• motile
• virulence factors
  • luekotoxin
  • LPS- an exotoxin that is effect on its target from a distance. It forms pores in neutrophils, granulocytes, monocytes,and some lymphocytes causing cell death
• associated with gingivitis, chronic perio disease, LAP and periimplantitis
• less virulent than P. gingivalis

fusobacterium nucleatum

• gram -
• rod (cigar shaped with pointed ends)
• anaerobic
• virulence factors
  • LPS
  • apoptosis in PMNs
  • can trigger the release of cytokines, elastase and oxygen radicals
  • coaggregates w most oral microbes there for it is an important bridge btw primary and secondary colonizers
• associated with gingivitis, chronic perio, and LAP
  

peptostreptococcus micros

• gram +
• cocci
• obligate anaerobe
• virulence factors
  • lipoteicholic acid- an adhesion molecule on the cell wall
• associated with gingivits, chronic perio and periimplantitis

eubacterium

• gram +
• rod
• obligate anaerobe
• associated with chronic perio and LAP

eikenella corrondens

• gram -
• rod
• facultative anaerobe
• virulence factor
  • LPS
• associated with chronic perio, and LAP

spirochetes

• Spiral, motile organisms

• Gram negative

• Species include:

Treponema denticola (associated with PD)

Treponema vincentii (associated with NUG)

Treponema socranskii (associated with PD)

Treponema pallidum (associated with syphilis)

• Virulence factors:

Can migrate through viscous environments.

Can move through the GCF and penetrate both the epithelium and connective tissue

Can degrade collagen

Can degrade dentin

Can produce proteolytic enzymes that destroy IgA, IgM, IgG, or complement factors

Matrix Metalloproteinase

Family of zinc dependant enzymes.

Produced by many cells including:

Fibroblasts, macrophages, epithelial cells and neutrophils.

Released by PMNs after phagocytocisis.

Degrades collagen

Can be synthesized within seconds in response to inflammation, produced by most cells, but in inflammation neutrophils and macrophages are good sources.  Causes vasodilatation and increased vascular permeability, promote overproduction of destructive MMP’s and stimulates bone resorption.

1. transport to surface by fluid flow or movement of motile bacteria

2. initial adhesion via chemical attraction/reaction

3. attachment via adhesins and complementary receptors

4. colonization

1. helps with adherance to the surface
2. extracellular slimlayer protects the biofilm from antimicrobials/host defences
3. fluid channels allow for transport of nutrition and removal of wastes

1. attachment- can be inhanced by adhesins in saliva or inhibited by IgGs in saliva
2. metabolism/nutrition-
   

• stress on metabolism: if environment is not favorable bacteria has to spend a lot of energy to protect itself and to obtain nutrition. This is not condusive to bacterial proliferation.
• nutrition:Carbs such as sucrose and lactose are readily available in most of our diets for bacterial metabolism.
• pH variations: acidic environments favor pathogenic bacateria
• presence of O2- as plaque mature O2 is reduced favoring more anaerobic/pathogenic bacteria

3. mechanical removal - inhibits maturation of plaque

4. location- easiest ---> hardest

• lower jaw
• molars
• buccal surfaces
• interdental

5. gingival inflammation: ↑ inflammation= ↑ GCF which favors adhesion and growth of bacteria thus more plaque

6. age- does not increase quantity but can increase host response thus pts susceptability to disease

7. spontaneous cleaning- eg eating fibrous foods. Found to have very little affect on amount of plaque.

8. smooth vs rough surface: rough surfaces favor plaque adhesion and accumulation

9. dentin tubules: plaque can adhere inside tubules