Week 3 Flashcards
Steps in colonization of the oral cavity starting with birth?
Day 1- facultative and aerobic bacteria from birth
Day 2- anaerobic bacteria found
Day 14- mature microbiota established in gut
2 years- whole microbiota formed 10^14 total
Tooth eruption = more complex flora
Is the oral microbiota harmful?
No most are commensal and or beneficial
How much bacteria do we have in and on our bodies?
~ 2 kg
How many different types of bacteria are found in the mouth?
Over 600
When infection with a microbe happens what are the choices and how much damage happens over time?
Commensalism- no damage over time unless it gets out of control and leads to disease- in which case it damage amount goes up over time.
Colonization- damage goes up over time and can lead to clearing the infection, disease, or persistence.
Both colonization and disease can lead to persistence where damage level is constant and high over time
Disease has two outcomes: death or eradication by immune or tx
Name the 6 major ecosystems in the mouth?
- Keratinized intraoral supragingival tissue and hard surfaces
- Perio pocket (including around implants)
- Non-K tissues- buccal, palate and floor of mouth
- Dorsum of tongue
- Tonsils
- Saliva
3.
Describe plaque and the locations it is found?
Structured, layered, yellow grey,
Found on hard surfaces of teeth and restorations both above and below gums
What is materia alba?
White cheesecake like substance that is soft and easily sprayed off with water made from salivary proteins, bacteria, dead epithelial cells and some occasional food debris.
No organizational structure
What is plaque made of?
Bacteria in a matrix of salivary glycoproteins and extra cellular polysaccharides
It is a biofilm
Can plaque be removed by sprays or rinsing?
Nope impossible needs physical scraping
What is dental pellicle?
A substance that coats every surface of the mouth derived from saliva made of glycoproteins, proline rich proteins, phosphoproteins, histidine rich proteins and enzymes
Aka proteins that are a mix of glyco, phospho, histidine and proline combined with enzymes
How does dental pellicle adhere to teeth?
Electrostatic, Vanderwalls and hydrophobic forces
How fast does pellicle form after cleaning teeth?
Within nanoseconds
3 major phases of plaque formation?
- Pellicle forms
- Initial adhesion and attachment of bacteria
- Colonization and plaque maturation
Three phases of bacterial attachment?
- Random contact of bacteria with hard surface aka transport of bacteria to the tooth surface
- Initial reversible adhesion
- Attachment with a firm anchorage by reactions between bacterial adhesins and pellicle receptors
After Step 3 it needs to be scraped off aka physically removed
Which phases of bacterial attachment are non specific?
Phase 1 and 2 are random and phase 3 depends on specific interactions between bacterial surface proteins (adhesins) and pellicle receptors
Why are teeth so good at accumulating plaque?
Hard non-shedding surface to attach to
A part of our ectoderm that doesn’t shed providing a home and “port of entry” for perio pathogens
When full mouth extractions are done does the type of bacteria in the mouth stay the same?
No key perio pathogens disappear
Describe the specific location of plaque growth on teeth?
Starts at gingival margin and interdental spaces and grows toward the corona
What is Supragingival plaque?
Plaque located outside of the perio pocket that starts at the gingival margin (touch’s the margin)
What type of bacteria makes up the first layer (touching the tooth) of supragingival plaque?
Gram positive cocci and short rods
What type of bacteria makes up the outer layer (surface) of supragingival plaque?
Gram negative rods and filaments, spirochetes
What is a major factor is causing plaque to stick to the surface of teeth?
The roughness of the surface.
Fine polishing paste or glycine powder for air polishing
What does thicker plaque contain and is it more or less pathogenic?
More pathogenic
Contains more motile bacteria like spirochetes and is packed denser so more organisms
What areas of the mouth does plaque form the fastest?
Lower, interproximal, buccal areas of molars…
IP is faster than straight buccals and lower molars traps food easier
Does plaque form at the same rate on people?
Nope varies a lot
What can explain 90% of the variations in the rate of plaque formation?
Salivary induced aggregation and relative flow
Does more or less saliva cause plaque to form faster?
More saliva= faster
Other than amount of saliva what are some other factors in plaque formation?
Diet, Chewing fibrous foods, Smoking, Brushing tongue and palate, Antimicrobial factors in saliva, Inflamed gingiva
Does age influence plaque formation?
No
Does plaque in older or younger people leave to more gingivitis?
Older
Does eating remove plaque?
Nope
What makes sub gingival plaque different?
Different environment,
Availability of blood products and an anaerobic environment
Do strict anaerobes contribute to initiation of periodontal disease?
Most likely very little but it is under debate
Not sure yet what exactly causes the consequences of the disease
Can sub gingival plaque be removed completely?
No it is really hard to do so
What is left allows for recolonization
Can some sub gingival plaque pathogens penetrate soft tissue and dentin?
Yes they can
How fast does sub gingival plaque recolonize after a cleaning?
7 days it is back to pretreatment levels
How does tooth associated sub gingival plaque versus tissue associated sub gingival plaque vary throughout the pocket?
Tooth associated subgingival plaque is more like Supragingival plaque than tissue associated.
What bacteria does TISSUE associated sub gingival plaque contain?
Mostly- gram negative rods and cocci
Others- filaments, flagellated rods and spirochetes
Do plaque colonies share resources?
Yes there are fluid channels that nutrients run though
Plus they communicate with each other via quorum sensing
What binds lower layers of plaque together?
Polysaccharide matrix with both organic and inorganic materials
Can perio and cariogenic pathogenic bacteria be transmissible to other people?
Yes both are transmissible- most common is vertical transmission in families.
Familial horizontal is less common
Can pathogenic bacteria be translocated from one place in the mouth to another?
Yes is can be spread with things like proxa brushes
List non bacterial organisms that live in the mouth too?
Viruses,
Fungi/yeast,
Protozoa,
Archaea
3 plaque hypotheses that have been discarded by now?
- Non-specific plaque hypo- control plaque and you control the disease
- Specific plaque hypo- only certain plaque is bad and if you have it then you get the disease
They still didn’t know if it was causal or correlation - Ecological plaque hypo- little deeper both plaque levels and specific bacteria along with the disease along with some host factors
What is the current accepted hypothesis on perio and plaque?
Keystone Pathogen Hypothesis
What does the Keystone Pathogen Hypothesis say?
A specific pathogen P. gingivalis is present in low numbers but it can disrupt the perio microbiota leading to dysbiosis.
What type of bacteria is associated with health?
Mostly Facultative- Gram positive rods and cocci
With a few anaerobic both pos and neg rods along with positive cocci
What type of bacteria is associated with gingivitis?
Main point- The levels of anaerobic bacteria gram negative rods and facultative gram negative rods increases
There are gram positive rods and cocci around along with negative cocci
Extra details-
Levels of facultative gram + rods and cocci decrease
Small amounts of anaerobic + cocci turn into - cocci
Anaerobic + rods decrease
What type of bacteria is associated with periodontitis?
Anaerobic gram negative rods 75%
Anaerobic gram positive rods ~12%
Spirochetes as well now
The rest are facultative gram positive rods and cocci
Take away- during gingivitis anaerobic gram neg rods increase in numbers along with facultative gram neg rods then the anaerobic neg rod take over in Periodontitis
90% of the bacteria present in Periodontitis is anaerobic
Gram positive rods and cocci = good
What does the rate of plaque growth on unbrushed teeth look like?
Exponential at first
First 24 hrs slow,
Next 3 days rapid
After 4 days it slows and shifts to anaerobic and gram negative
How much of the bacteria present is periodontitis is anaerobic
Most approximately 90%
List common bacteria associated with gingivitis names?
Don’t have to know this yet but made this card to start to get familiar with them.
Gram +: streptoccus, actinomyces, eubacterium and parvimonas
Gram - : capnocytophaga, fusobacterium, prevotella, campylobacter gracilis, C. consisus,B. parbula, E. corrodens