To understand that bacterial colonization begins at birth.

a.   Within hours of birth

b.   Anaerobic bacteria can be found in an infants mouth within 48hrs

c.   Mature microbiota can be found within 2wks

d.   Completely formed microorganisms 1x1014

   Most bacterial colonization is a commensal relationship which  is beneficial to both parties

1.) Increase bacterial load

2.) Increased pathogenicity

3.) Reduced host response.

Understand that once a tooth erupts into the oral cavity, bacterial colonization begins.

1.)   Teeth and implants:

a.     Provide hard not shedding surface for bacteria to hold onto.

b.    Allow the development of extensive structured bacterial deposits.

c.     Teeth are the primary habitat for periopathogens!

d.    With full mouth extractions –pathogens are low in concentration.

To be able to identify the major ecosystem for periodontal pathogens.

Hard surfaces that are supragingival.

Periodontal Pocket

Buccal epithelium, palatal epithelium, floor of the mouth

Dorsum of the tongue

Tonsils

 To understand the difference between dental plaque and materia alba.

a.     Plaque is primarily composed of bacteria in a matrix of salivary glycoprotein's and extracellular polysaccharides

b.    Materia alba = soft accumulations of bacteria and tissue cells that lack the organized structure of dental plaque. It is easily displaced with a spray of water.

To understand the differences between supragingival and subgingival plaque.

Supragingival plaque: Gram+ cocci and short rods/gram - rods and filaments on the outer surface of mature plaque.  Uses circulating carbs from saliva and GCF

Subgingival plaque:  Anaerobic uses tissue and cellular breakdown products and carbs from GCF and serum

To understand the differences between the nutritional sources for supragingival and subgingival plaque.

n  Supragingival: uses circulating carbohydrates from the saliva and GCF.

n  Subgingival: uses tissue and cellular breakdown products and carbohydrates from GCF and serum.

To identify where subgingival plaque attaches.

Below the gingival margin

To identify which group of subgingival bacteria are the most virulent.

 To understand the four stages of bacterial adhesion and attachment

1. Transport to the surface
2. Intial adhesion
3. Attachment
4. Colonization of the surface and biofilm formation

To understand how a “corn cob arrangement” is formed.

   Long-standing supragingival plaque near the gingival margin demonstrates "corncob" arrangement.  A central gram-neg. filamentous core supports the outer coccal cells, which are firmly attached by interbacterial adherence or coaggregation

To understand how “biofilm” helps bacterial plaque.

• Adhere to the tooth
•  Embedded in an extracellular slime layer-protects the colony from antibiotics, antimicrobial, and host defense mechanisms
• Has fluid channels-brings in nutrients

1. Bacterial Attachment

Enhanced – Adhesins in saliva

Inhibited – IgA secreted in the saliva.

2. Bacterial Metabolism and Nutrition

Stress on cellular metabolism

Availablity of nutrients

PH variations

Presence of oxygen

3. Mechanical cleaning.

Describe the affect that variations within the dentition have on bacterial load.

Early plaque forms more easily:

Lower jaw

Molar areas

Buccal tooth surfaces

Interdental regions

Describe the affect that gingival inflammation has on bacterial load.

• Gingival inflammation = increase GCF.
• Increased GCF favors both adhesion and growth of bacteria.
• SO…..the more inflammation a patient has = more plaque formation .

• Studies show that age has nothing to do with bacterial load
• However, when subjected to the same amount of plaque the older patient will have higher inflammatory response.
• Increased susceptibility to gingivitis with age.

Understand the difference between mechanical and spontaneous cleaning and their affect on bacterial load.

Spontaneous cleaning is negligible 

Mechanical cleaning is the only why the physicaling remove plaque

The smoother the tooth surface the less bacterial load

The rougher the higher the bacterial load

Clearly define transmission, translocation/cross-infection of bacteria.

 Transmission:  Movement of bacteria from one person to another….mother to child

 Translocation:  Intraoral transmission of bacteria from one niche to another niche….cross infection

a.   Susceptibility of host

b.   Presence of a large quantity of pathogenic species

c.   The absence or a small proportion of beneficial bacteria

1. Susceptibility of the host.

2. The presence of a large quantity of pathogenic species.

3. The absence or a small proportion of “beneficial “ bacteria.

These types of bacteria can….

                                         i.    Occupy a niche that may otherwise be colonized by pathogens

                                        ii.    Limiting pathogens ability to adhere to tissue

                                      iii.    Adversely affecting the vitality or growth of a pathogen

                                      iv.    By affecting the ablity of a pathogen to produce virulence factors

                                       v.    Directly degrading virulence factors produced by a pathogen

Understand how the 3 models for disease have changed over the years.

• 1965 -1975…..non-specific response
• 1975 –1985….bacterial specificity
• Today….altered host response

Understand today’s concept for periodontal disease.

 Specific bacteria signal a normal host response

Which bacteria are present in gingivitis? Give examples.

Primarily gram positive bacteria of the streptococcus and actinomyces species.

                                                                                 i.    S. sanguis

                                                                               ii.    S. mitis

                                                                             iii.    A. viscosus

Which bacteria are present in pregnancy-associated gingivitis? Give examples.

  P. intermedia

Which bacteria are most cultivated at high levels in active sites of chronic periodontitis?

• Gram negative bacteria 75%
• Anaerobic bacteria 90%
• Spirochete numbers have consistently been elevated in sites with chronic periodontitis. (Eg. Treponema denticola)

 Why are antibiotics often needed when treating localized aggressive periodontitis?

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

What systemic problems are associated with necrotizing gingival and periodontal diseases?

Malodor, pain, fever, malaise

What bacteria are associated with necrotizing gingival and periodontal diseases?

P. intermedia

Spirochetes:  Treponems vincentii

 Which spirocyte is associated with necrotizing gingival and periodontal diseases and why is it so virulent?

Treponems vincentii

Because it can invade necrotic tissue and apparently unaffected connective tissue

What is periimplantitis?

Inflammotory affecting the tissues around an already osseointgrated implant

What bacteria are associated with periimplantitis?

Gram –rods

Motile organisms

Spirocytes

Anaerobic microbes

What is the difference between facultative and obligate anaerobes and aerobes?

Facultative anaerobes can survive w/ O2 but can prefer w/o

Obligate can only survive one way

Gram + cocci and short rods on the tooth surface

Gram - rods and filaments on the outer surface

Gram -...rods, cocci, motile organisms, spirocytes

These can invade gingival connective tissue and be found on alveolar bone and in dentinal tubules

1. Adhere to the tooth

2. Embedded in the extracellular slime layer which provides protection against

       antibiotics

       antimicrobials

       host defense

3. Fluid channels which allow nutients to come and go

Smoking

Diabetes

Stress

Interleukin 1 genotype positive

gram neg anaerobic spirochetes

Treponema denticola

gram neg anaerobic rods

Actinobacillus aggregatibacter

1. P. gingivalis
2. E. corrodens
3. C. rectus
4. F. nucleatum
5. B. capillus
6. Eubacterium brachy
7. Capnocytophaga

P. intermedia

Spirochetes:   Treponema vincentii

What bacteria would you find around implants?name the 7 organisms

Gram-negative rods

Motile organisms

Spirocytes

Anaerobic microbes

1. A. aggregatibacter
2. P. gingivalis
3. T. forsythia
4. P. micros
5. C. rectus
6. Fusobacterium
7. capnocytophaga

• On the cell walls of gram + bacteria
• Thought to be an adhesion molecule
• Shows signs of virulence

Endotoxin

On the cell wall of gram - bacteria

Exotoxin

Leukotoxin is effective at a distance from its target cell.

What does Collagenase do?  

 destroys connective tissue

What does Collagena Protease do?

Cleaves IgA and breaks down protein.

Describe Prevotella intermedia and Prevotella nigrescens

Nonmotile

Gram-negative rods

Virulence factors:   LPS

Prevotella species are less virulent than p. gingivalis. P.I is associated with Pregnancy Gingivitis

Campylobacter rectus

One of the rare motile organisms

Gram-negative rod

Virulence factors:

Leukotoxin

LPS

C. rectus is less virulent than p. gingivalis

Fusobacterium nucleatum

Gram-negative rod (cigar shaped with pointed ends)

Anaerobic

Virulence factors:

LPS

Induces apoptotic cell death in PMN’s

Can trigger the release of cytokines, elastase and oxygen radicals.

Fusobacteria coaggregate with most oral microorganisms therefore they are an important “bridge” between the primary and secondary colonizers.

Peptostreptococcus micros

One of the rare cocci in periodontitis

Also one of the rare gram +

Obligate anaerobe

Lipoteicholic acid is an adhesion molecule on the cell wall of gram+ bacteria. Thought to be a virulence factor.