Dental Plaque Specific Bacteria Theory Flashcards
Requires 3 Factors + Time
Tooth
Bacteria
Substrate (fermentable carbohydrates)
Sometimes referred to as the ___ ___because time is often considered to be the fourth factor. It depends on the author who is reporting or running the study.
Caries Quad
Infectious Disease Process can be transmitted from person to person true or false
true
Multi-species – the mouth is host to 150-800 different species of bacteria at any one time
Collectively called _____ – this refers to the groups, or colonies of bacteria
Involves destruction of mineralized tooth surfaces (enamel & dentin)
biofilm
The 3 major players of the infectious disease process
Main Player- streptococcus mutans
Main Player- lactobacillus acidophilus
Actinomyces israelii
Plays a role in root caries
Actinomyces
What is plaque formation
Microbial biofilm adapted to its environment
Plaque involves 2 different types of adhesion to surfaces
Produces extracellular coatings & ___ ____ to help more bacteria adhere to biofilm
- Physiochemical
- Biochemical
surface fibrils
Plaque requires what kind of removal
mechanical
Plaque Biofilm as an Infectious Disease:
other Infectious diseases:
- Heterogenous
- Community “Whatever benefits the whole”
- Higher Resistance
- Fluctuations in cell structure
Other:
- Homogeneous
- Non-community (in it to win it, its all about me)
- lowered resistance
• The _____ means that the group of bacteria has a higher resistance to the therapeutic agents that we use. Where as, in an infectious disease that has a single bacterium as the culprit means that the resistance to “attack” is much lower.
heterogeneity
There is communication between bacteria in the plaque community. This means that if one area is being “attacked” the other areas can ”__ ___” and fortify the area of attack. This makes bacterial plaque difficult to kill!
send help
Plaque Biofilm is
Naturally acquired from:
Composed of:
- Food
- Human Contact
- Pets
- Atmosphere
Composed of:
Salivary components
Microorganisms (organized into communities
Intracellular matrix
Cell-to-Cell Communication
- Micro-climates
- Resistance to exogenous antimicrobial agents
- Mechanical oral hygiene practices are critical
Prior to Tooth Eruption:
____ pellicle
- Exists prior to tooth
Subsurface
Prior to Tooth Eruption:
____ pellicle
- Exists prior to tooth ___
Consists of:
Considered Endogenous
Subsurface
Eruption
Reduced enamel epithelium
Basal Lamina
Considered Endogenous
The tooth erupted. Now what?
The REE is digested by salivary and bacterial enzymes
Within seconds a thin microscopic coating of salivary components become absorbed onto the tooth surface
The tooth erupted. Now what?
The REE is digested by salivary and bacterial enzymes
Within seconds a thin microscopic coating of salivary components become ADSORbed onto the tooth surface
ADSORPTION
vs
Absorbtion
ADSORPTION is the adherence of one substance to a dissimilar substance
Absorption is one substance being taken up by another
Acquired Pellicle
Acellular
Contains:
Salivary glycoproteins
Receptor sites
Fills MILLIONS of microscopic tooth voids
Provides nutrients
Takes about one week to fully reform after removal from prophylaxis procedure
Adds a protective quality for the teeth& fills in those small nooks and crannies
Acquired Pellicle are Acellular meaning
no cells no bacteria.
Plaque uses ___ pellicle to “stick to the teeth”
acquired
The pellicle is made up of salivary glycoproteins which are responsible for
innate immunology of the oral cavity, they bind calcium phosphate ions to help remineralize teeth, provide a food source for both beneficial and harmful bacteria, and contain alpha amylase to help the process of polysaccharide breakdown. As you can see, it is a complex layer that coats each tooth.
To clarify, after the pellicle is removed by a professional prophylaxis, it begins to re-form within seconds. However, it is not fully formed and mature for a full week.
Plaque Components
70-80% bacteria
20-30% polysacchrides and glycoproteins
The polysaccharides help ensure a continuous food source in the event of “starvation” (when we don’t eat for a long period of time or when we eat foods that do not feed the bacteria)
In dental terms, the bacterial glycoproteins are ____ _____ located on the cell membrane that help other bacteria to adhere to the plaque biofilm. And they also help the cells to communicate with each other. It’s like a telephone cord to the other areas of the bioflilm!
carbohydrate chains
Formation of Dental Plaque
Bacteria tend to accumulate on teeth in sheltered undisturbed environments.
But they also accumulate on:
- Pits and Fissures
- Interproximal surfaces
- Gingival sulcus
Also
- Lips
- Cheek
- Palate
- Tongue
- Restorative Overhangs
May find plaque in areas you wouldnt normally find due to dry mouth
Explain the formation of plaque in detail after a prophylaxis
Dental pellicle forms within seconds of prophylaxis
In about 2 hours, bacteria loosely binds to pellicle (adsorption)
Bacteria multiples exponentially and spreads
Microcolonies form within the plaque matrix
Streptococci (multiple strains) secrete a protective slime layer
Maturation of the biofilm colonies
Microcolonies join to form larger, more complex, mutually beneficial groups (biofilm!)
Development of a primitive circulatory system
Able to adhere to acquired pellicle
Generally NOT pathogenic (S. sanguis to S. mutans)
Normally aerobic or facultative anaerobic
Gram positive
Primarily made up of cocci & short rods
Provides substrate microclimate for…
Primary Colonizers
Colonize on an EXISTING bacterial layer
Much more pathogenic (Lactobacillus)
Anaerobic (oxygen can only penetrate plaque to 0.1mm)
Usually gram negative (except for Lactobacillus)
Made up of rods, filamentous forms, spirochetes, etc.
Secondary Colonizers
Colonization Competition: Bacteria compete for sites
Host responds to the presence of pathogenic bacteria with:
- Immunoglobulins (antibodies)
- Enzymatic lysozyme
- Complement proteins
These host proteins originate from saliva and crevicular fluid
Beneficial and pathogentic competing for sites. Explain the process and how it relates to perio?
We are talking and focusing a lot on the pathogenic bacteria. But there are a large number of beneficial bacteria that are also present. These beneficial and harmful bacteria compete for sites on the pellicle and in the plaque biofilm itself. The best case scenario is that the majority of the plaque biofilm is beneficial bacteria.
As the numbers of the pathogenic bacteria increase, the number of beneficial bacteria decreases. Thus, caries (and perio) risk goes up! And, most (if not all) of the beneficial bacteria are the cocci and short rod, gram positive, aerobic bacteria. The pathogenic bacteria tend to be anaerobic in some form (facultative or otherwise), rods, spirochetes, motile, etc.
Once the host detects the pathogenic bacteria, the body responds through a variety of “seek and destroy” measures to remove the pathogenic bacteria. The body produces immunoglobulins from WBC that serve to identify and mark a non-host cell for destruction, releases phagocytic cells that provide lysozyme to “dissolve” the bacterial cell walls, and initiates the inflammatory response through complement proteins. The role of inflammation is to bring more antibodies, more WBC, more immunoglobulins to the area until the offending pathogens have been removed.
long columns of bacteria seen in the picture above.
formed through the competitive colonization that was mentioned earlier and results in the entombment of the bacteria nearest the enamel by the IPM.
Palisades
Palisades form
through competitive colonization
_______ occurs by an intercellular plaque matrix, more superficial bacteria, and saliva itself
Entombment
collection of dead bacterial cells, sloughed-off host cells from the oral cavity, blood cells, and food particles.
Materia alba
2 different theories of plaque
Non-specific plaque theory
Specific plaque theory
- States that it is the number of all bacteria within plaque that has a positive, direct correlation with the caries rate
- Groups all bacteria of the oral cavity together
- Ignores the individual characteristics of each bacterium
Non-Specific Plaque Theory
- States that it is specific bacteria within plaque whose numbers influence the caries rate – not all bacteria
- Considers individual genus and species of bacterium separately
- Considers the defining characteristics of each bacterium
Specific Plaque Theory
Consumes acidic wastes and turns them into less acidic waste products
xtra fact:
, in terms of caries, is considered to be a beneficial bacterium. It helps to regulate the metabolic waste products of bacterium such as S. mutans and by using it as a food source. Its own waste by-product is a less acidic material.
Veillonella
Formerly known as S. sanguis
Keeps acid production low
Direct competitive colonizer
Has links to infective endocarditis
Streptococcus Sanguinis
What are the 2 good bacteria
Veillonella
Streptococcus Sanguinis
2 Bad bacteria
Streptococcus mutans
Actinomyces israelii
- Produces lactic acid from glucose
- Highly acidogenic and therefore, acid-tolerant
- Associated with advanced caries & carious dentin
Lactobacillus acidophilus
- Kicks beneficial bacteria off the teeth and takes their place
- Disengages the gums
- Causative agent in antibiotic resistance
Porphyromonas gingivalis
2 Aciduric Bacteria
Strep mutans
- First cariogenic bacteria that are laid down
- High amounts of lactic acid as a result of metabolic wastes, which attracts…
Lactobacillus
- Lowers the pH
- Displaces Strep mutans
- Continues tooth demineralization
Plaque require what energy source
Fermentable carbohydrates
Plaque: Aciduric microorganisms produce:
-Acid
-Intracellular polysaccharides (provide energy)
-Extracellular polysaccharides (provide an anchor point)
/Glucans (dextran)
/Fructans (levan)
Plaque Exist Under Adverse Conditions
pH Temperature Nutrition Competing organisms Host inflammatory response Anaerobic conditions/oxygen competition
