Flashcards in Oral Micro II Deck (142):
Bacterial populations adherent to each other and to the surrounding environment (surfaces or interfaces), and enclosed in a Matrix are called what?
Maintained bacterial biofilms in the mouth generally cause problems.
Biofilms are a complex, cooperating, and competing community
What is the protective matrix made of that surrounds microcolonies of biofilm?
*also secreted ECM
The primitive/simple communication system used by microorganisms can be thought of as...
Once a quorum is sensed, a colony turns certain genes on and the biofilm can become _____ to antibiotics.
What is the most conspicuous biofilm in the mouth?
What 2 things happen as plaque increases in thickness?
Becomes less permeable to oxygen and saliva
higher conc. of toxic products, acids, inflammatory bacterial components
Plaque alters the environment to promote growth of different species
Too much plaque can lead to dental caries, which leads to consistent loss of periodontal ligament
Three types of flora:
Supplemental (minority of pop., generally act like normal flora)
Transient (brought in)
***also, there are Opportunists (part of normal flora that become bad actors when things go wrong)
Most Transient Flora causes problems
*difficult time colonizing
Some Transient Flora contain true pathogens and will cause overt disease.
The indigenous flora is often site specific and tend to recolonize, and aren't usually pathogenic at that site
What role of Normal Flora leads to Innate Immunity?
The fact that some women carry Staph aureus in their vaginal flora that is benign for them would be an example of...
*flora that exists in some individuals
What is a major bacterial species important for seeding the epithelium (and mouth) at birth?
(candida, etc also colonizes)
Actinomyces israelii is transmitted _______.
When the teeth erupt, new ______ develop.
*4 new niches
Initial plaque colonizers must be able to do what?
Adhere to teeth
Dental plaque ecology becomes relatively stable with the eruption of what teeth?
Primary 2nd Molars (around 2 yrs)
What bacteria can't hold onto the hard surface of the teeth?
Why is competition for a foothold in the mouth fierce for bacteria?
Most surfaces have high turnover or are flushed with saliva.
What teeth pioneer species (2 species) provide binding sites that other bacteria can secondarily grow on (increasing plaque)?
There is a direct link between the mother's S. mutans and the baby's
What is generally the 1st pioneer species of the tooth?
What is the second (appearing in pits/fissures around 2 years)?
Why doesn't S. mutans appear on the teeth until around 2 years?
Doesn't adhere well to smooth surfaces of teeth erupted up until that time
What bacteria doesn't appear in the mouth until later in life?
Supragingival plaque contains what 2 G+ bacteria?
Subgingival plaque contains what 2 G- bacteria?
(obviously more are present, these are good examples)
Streptococcus and Actinomyces
Treponema and Fusobacterium
Subgingival bacteria contain mobile forms
Supragingival metabolic byproducts tend to be _____
Subgingival bacteria always use what as a food source.
**caries caused by acidic environment in supragingival
What class of molecules allow Streptococci to be one of the major bacteria in the oral cavity?
*allows Strep to colonize most niches
Bacteria tend to grow what direction from the tooth surface?
(these multispecies complexes are held together by linking polymers = Biofilms)
If a biofilm becomes large enough, what no longer works to combat them?
A complex grouping of various bacteria species that adhere to one another, bacteria products, and salivary proteins.
What did a classic study of poor oral hygiene find correlated with gingivitis?
(general type of bacteria)
Anaerobic forms and rods
*Reversible after 21 days
If brushing stops, what increases?
What occurs as plaque increases in complexity and density?
Food Chains develop
What glucose polymers make up a good amount of matrix?
What vitamin is associated with periodontal disease?
What does it do?
Many forms of subgingival bacteria stink
What is the inflammation of gingival tissues, typically due to plaque build-up?
What 3 things differentiate Gingivitis from Periodontitis?
No irreversible destruction of perio ligament
No bone loss
No apical migration of junctional epithelium
Healthy to Acute to Chronic gingivitis is all reversible
Chronic gingivitis to Periodontal disease is reversible
Fluctuations in host defense capabilities brought on by stress, drugs, disease, etc, contributes to gingival disease outcome
The factors enabling the progression of Gingivitis to Periodontal disease are largely known
What are the 2 major categories of Periodontal disease?
* a third one is associated with Systemic Disease
Most periodontis pockets display what?
Climax Community Flora
Why do most of us develop chronic gingivitis?
Gingival inflammatory response ensures Bacteria don't invade tissues
*and this is ongoing
The key to inducing a bleeding gingivitis is the introduction of what?
One or more G- anaerobic bacteria
*also leads to Periodontitis
Initially (before gingivitis), what two species are dominant on supragingival plaque?
What species increases as plaque load grows?
Strep. and Actino.
Actino. is Microaerophilic
What organisms need the heme that inflammation provides?
What does this organism produce once it has heme?
LPS (highly inflammatory type)
***this leads to Bleeding Gingivitis
In a very basic sense, the Loe experiment demonstrated what?
When Good bacteria decrease Bad increase
Chronic marginal gingivitis is a ________ inflammatory response to supra-gingival plaque
Who did the experiments that definitively laid out the relationship between oral hygiene, plaque, and progression of gingivitis?
*also found gingivitis reversible after 21 days
What might initiate gingival disease progression?
Interruption of "balance" of normal bacteria/host defense
Name 5 factors that influence Gingivitis
Hormonal changes (pregnancy)
Drugs (cyclosporin, Ca channel blockers)
Oral Habits (chewing, smoking, mouth breathing, etc)
The severity of gingivitis depends on the balance between what?
Plaque bacteria and Immune response to it
What is characterized by painful gingival lesion with gray pseudo-membrane that readily sloughs revealing bleeding and necrosis?
NUG - Necrotizing Ulcerative Gingivitis
aka Vincent's Infection
What is the onset time of NUG?
Where are the lesions usually found?
Interdental gingival tips (papillae)
What population is NUG found in and why?
***elevated corticosteroids suppress immunity
What was a classic case of NUG in history?
How is NUG different from most bacterial invasions in gingivitis?
What causes the bad breath?
Treponema spp (G- spirochete)
Prevotella intermedia (G- rod)
(they produce noxious sulfur)
NUG is most often seen in young adults from 16-30 years.
The more severe sub-saharan disease (90% mortality) is called NOMA and causes massive facial damage.
NUG is 70% Gram- Rod
What are the 3 main zones of a NUG lesion?
Red bleeding necrotic zone
Deeper tissue of tissue being invaded by G-
NUG is associated with decreased host immunity, especially in regard to _____.
One of the major causes may be increased levels of ______ in response to stress.
What % of americans have periodontal disease?
What is the most predictive factor?
Name 4 factors in Periodontal disease pathology
Age, Poverty, Tobacco, Systemic diseases (diabetes), medications, crooked teeth, pregnancy, Red complex bacteria, Heredity, and oral hygiene are all factors in Periodontal disease.
Two defining results of Periodontal disease.
Periodontal ligament destruction
Loss of collagen attachment persists after the active periodontal disease process has ceased
Can attachment loss indicate if perio disease is ongoing or a result of previous manifestation?
Most periodontis is due to what?
Loss over a lifetime
Periodontitis is a polygenetically influenced disease
Periodontitis could be due to multiple _____ or multiple ______.
synergistic factors in susceptible hosts
Why is it not clear what specifically causes active periodontal disease?
Bacterial products damage tissue
Inflammatory factors damage tissue
*Imbalance may cause perio disease
An as yet unknown oral organism may be the causative agent in perio disease.
Unique combinations of organisms along with impaired host immunity may cause perio disease
What are the 3 major hypotheses of Perio Disease?
Specific mechanisms, multiple bacteria
Multiple mechanisms, multiple bacteria
As far as treatment is concerned, what are the 3 Hypotheses of Perio Disease?
Nonspecific Plaque Hypothesis - all plaque bad (mow lawn)
Specific Plaque Hypothesis - Certain plaque pathogenic
Dysbiosis - Ecological imbalance causes biofilm and disease
What does Dysbiosis involve that disproportionally effects environment?
**may be part of Dysbiosis theory
List the 5 major suspected Periodontal pathogens, starting with the 3 that make up the Red Complex.
Which bacteria is most associated with Chronic perio?
Which bacteria is most associated with Aggressive perio?
Porphyrymonas gingivalis (chronic)
Aggregatibacter a. (aggressive)
3 damaging microbe products:
Toxic metabolites (ammonia)
Name 2 defense inhibitors deployed by microbes causing Perio disease?
decrease PMN migration
decrease T/B-cell function
Type I-IV immune hypersensitivity is kicked off by an unknown antigen in Perio disease. (?)
What is also bad?
Koch's postulates generally don't work with Periodontitis. What replaced these?
What gram stain tends to be good for Perio disease and bad for caries?
7 features of Aggregatibacter actinomycetemcomitans:
Caphophilic (loves CO2)
pH 7-8, slightly alkaline
Increased growth with Steroid Hormones
Pound for Pound, A.a. makes what?
The LPS vesicles (blebs) of A.a. do what 3 things?
LPS activates Macrophage
releases Leukotoxin (cytotoxic exotoxin for PMN's, Macrophage)
Stimulates osteoclasts (via protein)
A.a. is found in ___% of ___ in adult periodontitis
A.a. is found in 90% of _______
Aggressive juvenile Perio (localized)
5 features of Porphymonas gingivalis (P.g.)
Asaccharolytic (protein major food source for G-)
Name 5 virulence factors for P.g.
LPS (much much less inflammatory)
What is a major difference between A.a. and P.g.?
LPS is very stealthy in P.g.
In terms of A.a. and P.g., how does Periodontitis change with age?
A.a. dominant when young
P.g. dominant when old
Where are A.a. and P.g. found in the mouth?
A.a. - specific sites
P.g. - everywhere
P.g. and A.a. are found in what numbers in a healthy mouth?
Small numbers - .005%
A.a. is associated with what type of periodontitis?
LAP (localized aggressive perio)
GCP (generalized chronic perio)
LAP shows what ethnic bias?
There is a ____ fold difference between European population and African in the US of LAP
(and African American in the US)
P.g. dodges Antibody complement
Oxygen is removed from the sulcus by organic molecules, creating an anaerobic environment.
The low levels of saliva/food in the sulcus means most bacteria will dine on what?
Because salivary washing isn't much of a factor in the sulcus, what virulence factor is no longer very important?
The different surfaces of the gingival sulcus create what?
More complex environment
The major function of PMN's in the gingival sulcus is what?
What controls the mechanisms of attachment loss in perio?
Th cell direction
Why is tooth loss not a bad thing systemically?
Removes the insult
What is damaged with increased bacterial penetration into the sulcus?
The role of the large B cell buildup upon bacterial invasion of the junctional epithelium isn't well understood
IL-1 switches fibroblast function from collagen production to production of what 2 things?
(this is upon bacterial invasion of the junctional epithelium)
IL-1, TNF-alpha, and PGE2 switches bone repair to what?
(upon bacterial invasion of jct. epi)
North Africans have a higher rate of LAP that other populations due to what clone (bp deletion) in what species?
The JP2 clone in A.a. is more pathogenic why?
Leukotoxin production maxed
JP2 clone doesn't spread easily to Europeans.
What is the term for inflammation of the pulp?
Pulp tissue responds to insults with what process?
Why will pulp become quickly necrotic?
Poor collateral circulation
What is the most common way for pulp to become infected?
What are the initial bugs that make it through the dentin into the pulp?
*then taken over by Perio bugs like Pg and Aa
In a carious lesion, ______ chops at enamel and ______ is the first to hit the pulp.
Two forms of pulpitis:
Reversible (insult removed)
Name 3 mononuclear cells:
Macrophage, T-cells, B-cells (also NK cells)
Look for ____ in acute pulp infection and _____ in chronic infection.
*both these cells cause significant damage themselves
What is the term for microbial leakage out of the root apex and destroying surrounding bone tissue in pulp infection?
Dental pulp is generally free of viruses. What is one exception?
How was the bacterial damage in pulpitis definitively shown?
Germ free animals didn't develop
At what point in penetration of the tooth does bacteria reach the pulp?
Once Dentin reached, bacteria can travel down tubules
Infection precedes carie in this way
What type of inflammation usually occurs as infection precedes the carie reaching the pulp?
What occurs in Dentin during this process?
Chronic - mononuclear dominated (Macrophage, T/B cells)
Bacteria induce reactionary/reparative dentin
The type of pulpal inflammation tissue is capable of recovering from (once noxious stimuli removed) is called?
*during which time a tooth may be saved
Once ______ reaches the pulp, irreversible inflammation sets in.
Pulp infections are almost always polymicrobial
What type of microorganisms dominate infected pulp?
Subgingival, G-, facultative/anaerobic
The G- facultative/anaerobic bacteria infecting pulp is made up of how many species?
What is a G+ bacteria commonly associated with Pulpitis?
Name 5 G- bacteria commonly associated with Pulpitis
The bacteria infecting the root canal mirrors bacteria infecting _____
What identification problem is the same in Periodontal disease and Root pulp infections?
Instigator bacteria vs. follower bacteria
Describe the 2 step treatment course for Infected Dental Pulp.
Mechanical/chemical elimination of Agents
Bacteria in biofilms can be up to _______ less sensitive to anti-microbial agents.
How is this often achieved?
Communication (quorum sensing)
*latter may explain the smoldering effect followed by explosion in many infections