2. Biology of Dental Plaque II Flashcards
Numerous Distinct Microenvironments Within Biofilms
• Who came up with biofilm: \_\_\_\_ (Bosman, Montana) • Attachment of diff species of bac, as thickness of biofilm increases, changes in availability of nutrients: ○ Bathed by saliva - contains \_\_\_\_ - which is a carbohydrate; and proteins (if the bacteria are proteolytic) ○ Not all bacteria use carbohydrates, some are fermentative, some are proteolytic ○ Initial bacteria that bind are \_\_\_\_ bacteria • As biofilm gets thicker, there is a gradient for \_\_\_\_ • As gets thicker, avail of \_\_\_\_ decreases - getting to such a low level, anything that requires O2 won't do well • May be changes in \_\_\_\_ (\_\_\_\_ organisms will drop the pH) • Based on depth of plaque, as you go deeper in plaque there is a drop of O2 - in central mass there is virtually none - either \_\_\_\_ or \_\_\_\_ • Under diff nutrient avail - high carbs, there's a gradient; or can be in oxygen - in middle will be \_\_\_\_
Dr. Costaton sugar carb-loving carbs O2 pJ fermentative anaerobic facul. anaerobe fermenters
Primitive Circulatory System of a Biofilm
• Coral reef ○ Release ink on one side, as it disperses through, the ink will diffuse through all the channels ○ Will initially be dispersed uniformly • Channels are the "vessels" • Interactive network that affects different sites, and it is \_\_\_\_ • But bacteria that are close, it will be a \_\_\_\_ ○ Within the microenvironments, living right next to each
unidirectional
bidirectional
Primitive Circulatory System of a Biolfim
* Arrows - using carbohydrates, release \_\_\_\_ that affects what's happening downstream * What happens on one side, will have manifestations what's happening \_\_\_\_ (complete opposite of LV analogy) * Symbiotic, or mutualistic, or commensal, or antagonistic
acid
downstream
Metabolic Interactions within Oral Biofilms
The interactions can be commensal, synergistic, mutualistic or antagonistic
• Lactate (from carbohydrates from \_\_\_\_) can serve as GF for other organisms (\_\_\_\_) ○ Need these organisms present first ○ \_\_\_\_ relationship ○ Remember this! • Continues to build upon itself • Streptococcal that are \_\_\_\_, use oxygen, decreases the amount, and supports anaerobic organisms - \_\_\_\_, and \_\_\_\_ (strict anaerobe)
streptococcal vionella commensal facultative fusobacterium nucleatum p. gingivalis
Resistance to Mechanisms of Host Defense and Antibiotics
• What types of immune is important in removal of EC infections ○ \_\_\_\_ - IgA - prevent bacterium binding to \_\_\_\_, or can bind directly and activate \_\_\_\_ (IgG, IgM), and \_\_\_\_ acts as opsonin ○ Do neutrophils need Ab? No - can recognize presence by \_\_\_\_ and \_\_\_\_ on cells • Immune system has access to bugs in saliva, but to those deep in biofilm they are inaccessible • In biofilm, express \_\_\_\_ that allows to evade detection by immune system ○ Acts differently in \_\_\_\_ • Presence of biofilm and the matrix protects the bugs from immune and innate mechanisms of immunity • Green = antibiotic ○ Cxn in solution is high - \_\_\_\_ bugs are exposed to high cxn of antibiotic - die ○ As biofilm gets larger, and matrix develops, bugs in deeper parts are exposed to low cxn - they begin to become \_\_\_\_ or \_\_\_\_ due to low levels (immune inhibitory cxn?) § Resistance: selection of the bacteria that can evade the antibiotics
antibodies
surface
complement
C3b
MAMPs
DAMPs
genes
planktonic/biofilm
planktonic
resistant
unaffected
Resistance to Mechanisms of Host Defense and Antibiotics
• Living in biofilm alters geno/phenotype - become more apt to become \_\_\_\_ • Some orgs that grow at \_\_\_\_ - won't be affected by antibiotic • \_\_\_\_ - tolerate antibiotic, state that are unaffected (growth at slow rate) ○ When antibiotic that is no longer present, it will replenish the pop with \_\_\_\_ type • Transfer of genes, that transfers \_\_\_\_ - associated with how bugs live in biofilm • Bugs in biofilm are more resistant to antibiotics - clinical significance: don't use antibiotics to treat periodontitis, but when we do (17 yo with rampant bone loss) in cases with patients with a lot of bacteria; scaling and root planing (under ST to get tartar and biofilm off) in conjunction with antibiotics; do SRP \_\_\_\_, then do \_\_\_\_ ○ Disrupts biofilm, puts bugs in \_\_\_\_ state, where antibiotics can do their job ○ Direct clinical representation of this science
resistant
slow growth
persistors
resistant
resistance
first
antibiotics
planktonic
Interspecies Bacterial Communication within Biofilms
Mechanisms include:
physical interaction
physiological interactions
- metabolic cooperation/antagonism
DNA-mediated interactions
- genetic exchange
microbial intercellular signaling
- contact-dependent signaling
- qurom sensing• Bacteria can communicate
• Metabolic interactions
○ Cooperation/antagonism
• Quorum sensing; bacterial equivalent of ____ signaling
• Bacteriosin
○ Bacterial toxin that can affect ____ cells
cytokine
prokaryotic
Quorum Sensing:
A Mechanism of “Communication” Between Bacterial Cells
A process whereby small signaling molecules produced by bacteria are used by the cells to monitor the ____ of their population.
Typically, results in altered ____ expression and a subsequent change in bacterial “behavior” including increased ____.
• Bugs of \_\_\_\_ species or \_\_\_\_ species • As density gets higher, it would be beneficial for a bacterial cell to slow down process to make it favorable for themselves • VP - ability of bacterium to cause \_\_\_\_ ○ Deleterious to our survival, but beneficial to the \_\_\_\_
density
gene
virulence potential
same
different
disease
bacteria
Quorom Sensing
Cell density-dependent signaling system mediated by molecules known as ____ that are constitutively produced by bacteria during their growth.
Upon reaching a ____ concentration, binding of autoinducers followed by activation or repression of target ____.
The threshold concentration is reached only when cells are at a high ____; the bacteria sense that the population has reached a critical mass or ____.
Allows bacteria to display a ____ response that benefits the population.
* Release of signaling molecule - some affect same species, or some will affect other species - as long as they have the \_\_\_\_ * Can alter gene expression - can alter the overall behavior - slowing proliferation, resulting in a nutrient source won't be depleted and the bacteria will have more to eat
autoinducers threshold genes density quorum
“unified”
receptor
Quorum Sensing
• Types of behaviors that can be altered ○ \_\_\_\_, competence, \_\_\_\_, antibiotic production (toxin that one bug can produce to inhibit another), \_\_\_\_ (movement within the biofilm), and ability of bugs to form a \_\_\_\_.
virulence
conjugation
sporulation
biofilm
The EPS Matrix of Bacterial Biofilms
Composed of extracellular polymeric substances including ____, proteins, lipids and ____.
The contents of the EPS matrix are derived from ____, saliva and/or gingival crevicular fluid and the composition is highly variable depending upon the ____ of the biofilm.
- proteins, lipids, carbohydrates, extracellular DNA
- inorganic molecules
- ____, fungi, viruses, ____ - remnants of host cells• Spaces between the bacterial cells: EPS matrix
• Mainly produced by bugs in the biofilm
• GCF - liquid that is within the sulcus, that is derived from ____
○ Bacteria growing sub-gingivally, some of their ECM may be composed of proteins from ____
• ____ - may or may not be bacteria
polysaccharides
extracellular DNA
bacteria
microbial constituents
mycoplasma
protozoa
serum
GCF
mycoplasma
The EPS Matrix of Bacterial Biofilms
• Facilitates \_\_\_\_ of bacteria to substrate • Facitilates \_\_\_\_of additional orgs to biofilm • Bridging of bugs to species (\_\_\_\_) • Serves as \_\_\_\_ that holds the cells together ○ Reinforces \_\_\_\_ structure of biofilm
adhesions attachment aggregation cement 3d
The EPS Matrix of Bacterial Biofilms
• Do not memorize all of these • Can be a source of \_\_\_\_ to the bugs • Source of \_\_\_\_ information ○ EC DNA in EPS • \_\_\_\_ barrier ○ Relative to antibiotics and host immune system • Absence of this structure, the biofilm will not exist; NECESSARY FOR SURVIVAL OF \_\_\_\_
nutrients
genetic
protective
biofilm
Phases of Bacterial Biofilm Formation
The very first event in the formation of a bacterial biofilm is ____ of the surface onto which the bacteria will attach.
This is followed by: Phase 1: \_\_\_\_ Phase 2: \_\_\_\_ Phase 3: \_\_\_\_ Phase 4: \_\_\_\_ Phase 5: \_\_\_\_
"conditioning" initial attachment irreversible attachment growth maturation dispersal
Phases of Bacterial Biofilm Formation
Lag - ____
Log - ____
Stationary - ____
Death - ____
* Lag - early phases of attachment * Once attaches - proliferate * Cxn of cells is as high as it gets (nutirents, quorum sensing, competiton for mebtaolites) * Maturation - of the ECM * Depletion of nutrients, the biofilm falls apart and bugs fall into the \_\_\_\_ environment
attachment growth maturation dispersal fluid
A Few Basic Concepts About the Formation of Dental Plaque
- Dental plaque is a ____ biofilm the formation of which is a highly ____ process that gives rise to distinct microbial populations within its structure.
multispecies
ordered
A Few Basic Concepts About the Formation of Dental Plaque
- The specific bacterial organisms found in various types of plaque is dependent upon the ____ factors under which the plaque is developing.
- Plaque formation is a ____ process that is driven by constant ____ within the dentogingival environment and the plaque itself.
environmental
dynamic
ecological changes
Determinants of the Microbial Microenvironment 1. Host Factors: • \_\_\_\_ • gingival crevicular fluid (GCF) • \_\_\_\_ • oral hygiene habits • \_\_\_\_ • numerous others
• GCF - derived from \_\_\_\_ - contains proteins ○ \_\_\_\_ orgs • Saliva contains what you eat, and rich in carbohydrates ○ \_\_\_\_ bugs
saliva diet medical history/medications serum proteolytic carb-loving
Determinants of the Microbial Microenvironment 2. Bacterial Factors: • \_\_\_\_ • metabolic characteristics - oxygen requirements - preferred source of nutrients • production of toxins (\_\_\_\_) • coaggregation • factors affecting the \_\_\_\_
• Adhesins - critical to formation of \_\_\_\_
adhesins
bacteriocins
host response
dental plaque
Determinants of the Microbial Microenvironment
Potential Nutritional Interactions Between Plaque Bacteria (“____”)
food chains
Determinants of the Microbial Microenvironment 3. Local Physicochemical Factors: • pH • \_\_\_\_ (oxygen potential) • temperature • \_\_\_\_ availability
redox potential
nutrient
Determinants of the Microbial Microenvironment
• Cementum is apical to enamel ends • Soft tissue is attached to teeth - one component is \_\_\_\_, and the other is the \_\_\_\_attachment ○ JE/SE is only histologically seen • Apical to oral epithelium, tissue above red line is alveolar mucosa ○ Big histological difference: OE is \_\_\_\_, and AM is \_\_\_\_ ○ OE is bound to underlying bone, but AM moves (has a large number of \_\_\_\_ structures) ○ Structure that divides these two is the \_\_\_\_ • Probe slides into gingival sulcus (SE on lateral wall, tooth on other lateral wall and JE at the base) • Connective tissue attachment - collagen fiber bundles that impregnate in the cementum, covering the root of the tooth, that anchor the ST to this tooth • Distance between bone and base of JE is 2mm • With gingivitis there are changes: ○ Inflam cells, and disruption of JE and SE ○ All the tissue looks larger - \_\_\_\_ reaction in CT, BV dilate, and movement of fluid inducing edema - why it looks erythematous, swollen, etc. • Environment changes - deeper - living in GCF that has \_\_\_\_ from an inflam reaction, and the \_\_\_\_ cxn is much different (from the saliva, on the outside)
JE collagen fiber keratinized non-keratinized elastic MEJ inflammatory protein oxygen
Determinants of the Microbial Microenvironment
• With periodontitis: ○ Enviornmentally very different in the \_\_\_\_
periodontal pocket
Stages of an Infection
* Microbial infections dvelop * \_\_\_\_ first * Prolfieration, and invade * Induce \_\_\_\_ reaction * If inflam reaciton doesn't eliminate, then an \_\_\_\_ immune response
In a tooth…
• Enamel gets ____, bac attach to it
• As biomass increases in complexity, orgs start to inhabit biomass
• Can invade epithelial cells and get into gingival conn tissue
• And then an inflam reaction (____), and under adaptive immune response (develops into ____)
attachment
inflam
adaptive
conditioned
gingivitis
periodontitus
The Acquired Pellicle
1. Essentially ____ organic film that is deposited on teeth and facilitates ____
cell-free
plaque initiation
The Acquired Pellicle
- Salivary glands
- Oral mucosa
- GCF
- Oral bacteria• All of these provide molecules that can bind newly claend teeth and form the acquire pellicle
○ Salivary ____, salivary proteins, salivery ____, peptides and ____ from saliva, and oral mucosa and bacteria on teeth
• Major source - ____
glycoproteins
phosphoproteins
lipids
salivary glands
The Acquired Pellicle
- Essentially cell-free organic film that is deposited on teeth and facilitates plaque initiation.
- Formed mainly by ____ adsorption of ____ charged salivary proteins, glycoproteins and pep- tides to ____ charged phosphate groups on the surface of the tooth.
- The pellicle alters the ____ and ____ of the tooth surface thereby increasing the efficiency of bacterial adhesion.
- Selective process, not everything attaches to tissue surfaces
- Pellicle facilitates bumping of bugs onto tooth
selective
positively
negatively
charge
free energy
The Acquired Pellicle
- May contain minor components derived from ____ bacteria/host cells, ____ and food.
- Although it takes up to ____ days for the pellicle to fully mature, reformation starts ____ after tooth cleaning
dead
GCF
7
immediately
Components of the Acquired Pellicle
\_\_\_\_ Lysozyme Amylase Cysteine-containing Phosphoproteins \_\_\_\_ Proline-rich Proteins \_\_\_\_ Mucins
Many of these molecules can act as ____ for molecules found on the surfaces of bacterial cells.
* Don't memorize this * Moelcuels on bacterial cells are the \_\_\_\_ that stick to these structures * This list acts as ligands to which bacteria will attach themselves to
albumin
IgA
statherin
adhesions
Functions of the Acquired Pellicle
- ____ and protection against ____ damage.
- Regulation of mineral homeostasis; prevention of ____ and facilitation of ____.
lubrication
abrasive
demineralization
remineralization
Plaque Initiation
3 phases of bacterial attachment to the acquired enamel pellicle:
Passive transport:
Formation of ____
Reversible adsorption:
Weak, long range ____ attractive forces, ____ interactions and ____ bridging.
Irreversible adsorption:
Irreversible, specific, short range, interactions (____, ____ or ____ bonding) [facilitated by ____]
Random contact mediated through: - \_\_\_\_ transport in saliva - \_\_\_\_ -\_\_\_\_ bacterial movement
acquired enamel pellicle
van der waals
hydrophobic
calcium
ionic
covalent
hydroegn
adhesins
passive
sedimentation
active
Plaque Initiation Firm Attachment (Irreversible Adsorption)
Irreversible attachment of bacteria to a newly formed pellicle is initiated by ____ range, specific ____interactions between components of the pellicle (receptors) and ligands (____) on the surfaces of the bacterial cells.
Adhesins are ____ expressed on bacterial cells (some can adhere to acquired pellicle, and some cannot)
short
stereochemical
adhesins
differentially
Plaque Initiation Firm Attachment (Irreversible Adsorption)
Streptococcus Spp. - Adhesin: ____; Receptor: ____
Mutans Streptococci - Adhesin: ____; Receptor: ____
Actinomyces naeslundi - Adhesin: ____; Receptor: ____
antigen I/II
salivary agglutinin
glucan binding protein
glucan
type 1 fimbriae
proline-rich proteins
Plaque Initiation Firm Attachment (Irreversible Adsorption)
The EPS Matrix of Dental Plaque
____, a type of extracellular polysaccharide (EPS) that interacts with glucan-binding proteins (GBP) promote interactions between ____ cells and “____” their attachment to the developing plaque matrix.
____ released by bacterial organism, used in the biosynthesis of glucan molecules
In presence of this enzyme, glucan is made, other cells that have the GBP can bind to this bacterial cell; if enzyme is deposited on surface of tooth, it’s possible for the bacterial cell to interact with the pellicle
glucans
bacterial
reinforce
glycosyl-transferase
The Formation of Dental Plaque as Seen Through a Microscope
Identify individuals who needed crowns on their teeth > made temporary crown out of epoxy resin, and the patient wouldn’t brush their teeth for varying periods of time > plaque would form on the crowns
Following removal > process for ____ by light microscope/EM > would give snapshots over time of bacterial cells attaching to crowns
evaluation
Plaque Initiation: Days 0 to 3
THIS PROCESS STARTS ____!
Initial colonizers (____ species) of the acquired pellicle include:
- Streptococcus ____
- Streptococcus ____
- Streptococcus ____
- Streptococcus ____
- ____ naeslundii
These are ____, ____ cocci and rods that are ____-tolerated by the host.
actinomyces naeslundii is a ____-shaped organism
supragingivally
pioneer
gordonii sanguis oralis mitis actinomyces
gram-positive
facultative
well
rod
Plaque Initiation: Days 0 to 3
- Cell division leads to increased ____ and ____ spread of adherent bacteria.
- Subsequently, competitive growth leads to formation of ____ microcolonies composed of predominantly ____ cells.
Once they attach, and they begin to multiply and spread laterally until they bump into something that doesn’t allow them to go any further and ____ on top of one another
thickness
lateral
columnar
coccoid
proliferate
Plaque Initiation: Days 0 to 3
The Extracellular (EPS) Matrix of Developing Plaque
Matrix reinforces the overall structure of the developing plaque matrix, and other factors that are important in the maintenance/viability of the plaque
Following ____, you find large spaces between bacterial space; in situ, they’re filled up by EPS
dehydration
Plaque Initiation: Days 0 to 3
Components of the EPS Matrix of Developing Plaque
Organic Components:
• ____ proteins and glycoproteins
• lipids (derived from disrupted ____ and/or
____ cells)
• DNA
• bacterial polysaccharides (____ and ____)
Glucans/fructans are derived from simple ____
salivary/serum bacterial host glucans fructans
Plaque Initiation: Days 0 to 3
Components of the EPS Matrix of Developing Plaque
Inorganic Components:
• minerals (generally calcium and phosphorous
with trace amounts of sodium, potassium and fluoride)
—- supragingivally these are derived from ____ and subgingivally from ____
• subgingivally, blood “products” (e.g., ____ released from hemoglobin)
Dark plaque = close to ____/under margin (subgingivally) is due to the deposition of iron
saliva
GCF
iron
gingival margin
Plaque Initiation: Days 0 to 3
Functions of the EPS Matrix of Developing Plaque
- ____ to Surface
- Mechanical Stability
- ____ for 3-D Structure
- Nutrient Source
- Extracellular ____ System
- Reservoir of Genes for ____ Gene Transfer
- Protection (desiccation, oxidation,
biocides, antibiotics, host defense)
adhesion
scaffold
“digestive”
horizontal
Bacterial Interactions in Dental Biofilms
____ – adherence of two genetically distinct bacterial organisms, one of which is already attached to the ____ while the other is in it’s planktonic state. This is mediated via ____ specific receptor-ligand interactions between molecules on the surfaces of the bacterial cells.
Initially, this occurs between ____ species and between ____ species; this is followed by intergenic ____ between the two and with other species of bacteria.
Stereochemical interactions = ____ and ____
Require presence of ____ in order to attach; if you inhibit pioneer species you can stop plaque formation > ____ therapy (receptors for binding of additional bacteria are eliminated)
The bacteria that bind to the pioneer species are the ones that are involved with ____ and ____
coadhesion
biofilm
highly
streptococcal
actinomyces
coadhesion
adhesins
receptors
pioneer species
substitution
gingivitis
dental caries
Bacterial Interactions in Dental Biofilms
Coaggregation – adherence of two genetically distinct bacterial organisms while both are in their ____ state.
- the complex of coaggregated organisms can then ____ to the biofilm.
“Corncobs” – formed by interactions between ____ cells and ____-shaped or ____ organisms.
• at 3 days, organisms are most likely ____.
• at later stages, organisms tend to be ____.
planktonic
coadhere
coccoid
rod
filamentous
gram-positive
gram-negative
Bacterial Interactions in Dental Biofilms
Why coadhere or coaggregate?
- Increase probability that species that need to interact (cooperativity) will do so.
- Facilitate development of ____.
- Creation of environments needed for growth of particular species of bacteria (attachment of ____ anaerobes to ____ species).
- Facilitate cell to cell ____.
food chains
obligate
oxygen-consuming
signaling
Plaque Initiation: Days 0 to 3
____ and ____ contribute to diversification of the composition of the developing dental biofilm.
Not a random accumulation of bacterial cells on surface, it is an ____ process that gives rise to something with structural characteristics
coadherence
coaggregation
orderly
Plaque Initiation: Days 0 to 3
Early Supragingival Plaque
• Predominantly Gram-positive cocci and rods that tend to be facultative anaerobes.
Streptococcus \_\_\_\_ Streptococcus \_\_\_\_ Streptococcus \_\_\_\_ Streptococcus \_\_\_\_ \_\_\_\_ naeslundii \_\_\_\_ viscosus \_\_\_\_ spp. \_\_\_\_ parainfluenzae
- Organized as ____ microcolonies
- Well ____ by host
Includes the pioneer species of bacteria (the top 5), and there are 3 more that are included (they attach via ____ and ____, they require the presence of pioneer species)
oralis mitis gordonii sanguis actinomyces actinomyces veillonella haemophiulus
columnar
tolerated
coaggregation
coadherence
Plaque Initiation: Days 0 to 3
Early Supragingival Plaque
What’s happening to the local microenvironment as this process progresses?
____ O2 availability
____ temperature
____ CHO availability
Right > exposed to oral cavity
Deep down in plaque matrix: low O2 availability, at deepest recesses its an anaerobic environment; increase in temperature; carbohydrate availability is low deep within the tooth surface
decrease
increase
decrease
Plaque Initiation: Days 0 to 3
Coaggregation
____ have been found to coaggregate with the widest range of bacterial genera including early and late colonizers; but not with each other.
Since many late colonizers can not ____ with early colonizers it has been proposed that Fusobacteria act as a “bridge” between the two.
If not removed via mechanical forces > attachment of other organisms to supragingival plaque
The receptors used for attachment to ____ is different from those used to attach ____ to each other
fusobacteria
coaggregate
acquired pellicle
bacteria
Plaque Maturation: Days 3 to 60
- Increasing prevalence of ____ and-____ rods and filaments.
- Filaments, many of which are ____, grow into ____ plaque and eventually replace ____ cells.
Introduction of ____ bacteria during maturation
Called “bottle-brush” earlier, but you see an infusion of cell types deep down in matrix
Timeframe of maturation is highly ____ from individual to individual
gram-positive negative anaeorbic coccoid coccoid
gram-negative
variable
Plaque Maturation: Days 3 to 60
• Environmental changes within the developing plaque drive a transition towards an anaerobic microflora with the appearance of secondary colonizers:
- Streptococcus ____
- Streptococcus ____
- Actinomyces ____
- ____ nucleatum
- ____ intermedia
- ____ spp.
Bottom three are gram negative bacterium
sanguis milleri israelli fusobacterium prevotella capnocytophaga
Plaque Maturation: Days 3 to 60
• By approximately ____ weeks the plaque has fully developed. In the context of microbial ecology this is considered as a ____ and is referred to as ____ plaque.
3
climax community
mature supragingival plaque
Plaque Maturation: Days 3 to 60
In contrast to early supragingival plaque, mature supragingival plaque:
• is composed of a more ____ mixture of Gram-positive and negative organisms.
• contains ____, branching rods, filaments and ____.
• is composed of both ____ anaerobes and ____ anaerobes.
• is associated with the occurrence of ____ and ____.
equivalent cocci spirochetes facultative strict dental caries gingivitis
Plaque Maturation: Days 3 to 60
- Once supragingival plaque has developed into a “climax” community it is in a state of equilibrium between ____ and ____ of bacteria.
- Cells that detach from the plaque matrix enter the ____ state suspended in saliva and facilitate their being transported to colonize other sites in the oral cavity.
- If left undisturbed, the plaque can be “seeded” by mineralizing agents that lead to it developing into ____.
attachment
detachment
planktonic
calculus
Plaque Maturation: Days 3 to 60
Development of Subgingival Plaque
Subgingival environmental conditions are dramatically different from those found in the supragingival milieu:
• The O2 concentration is ____.
• It’s ____.
• Nutrients are derived primarily from ____ and are ____ as opposed to CHOs in saliva.
Appearance of ____ anaerobes, and ____ bacterial organisms will be apparent in subgingival plaque
low
warmer
GCF
proteins
strict
proteolytic
Plaque Maturation: Days 3 to 60
The conditions of the subgingival environment select for the growth of a unique microflora relative to that seen in supragingival plaque with the appearance of the [[late]] colonizers:
- ____ gingivalis
- ____ forsythia
- ____
- ____ spp.
- ____ spp.
- ____
porphyromonas tannerella AA selenomonas capnocytophaga spirochetes
Plaque Maturation: Days 3 to 60
The microbiota of subgingival plaque is:
- far less ____ than early or mature supragingival plaque.
- dominated by ____ organisms.
- dominated by ____ and ____organisms.
- composed of organisms that are mainly ____.
- associated with ____.
Capnophilic > like ____ in environment
organized gram-negative anaerobic capnophilic proteolytic periodontitis CO2
Plaque Maturation: Days 3 to 60
Development of Subgingival Plaque
Supra > ____ microcolonies, sub > highly ____, fully capable of forming on the surface of ____ (innocuous, except it’s a great nitus for formation of dental plaque)
Host cells are present, some are leukocytes and epithelial cells
columnar
unorganized
calculus
Dental Plaque
Plaque Maturation
It is not this clear as to where ____ ends and ____ starts!
Plaque Initiation
Formation of Acquired Pellicle
initiation
maturation
Dental Plaque
Please remember that although the diagram suggests the formation of dental plaque is a relatively static process, it is actually an extremely ____ series of events!
The composition of the microflora changes in response to alteration of the ____.
dynamic
local environment
Subgingiviaally, fusobacterium interacts with ____ and form subgingival plaque
late colonizers
Early Supragingival Plaque
• Predominantly ____ cocci and rods.
• Cells are organized as ____ microcolonies.
• Organisms tend to be ____.
Mature Supragingival Plaque
• Composed of a more equivalent mixture of ____ and ____ organisms.
• Contains cocci, branching rods, filaments and spirochetes.
• Composed of both ____ anaerobes and ____ anaerobes
Subgingival Plaque • Dominated by \_\_\_\_ organisms. • Dominated by \_\_\_\_ and \_\_\_\_ organisms. • Composed of organisms that are mainly \_\_\_\_.
gram-positive
columnar
facultative anaerobes
gram-positive
negative
facultative
strict
gram-negative
anaerobic
capnophilic
proteolytic
Considering dental plaque as a biofilm offers opportunities for the development of novel approaches to treat oral diseases.
Conventional Approaches:
- ____ plaque removal
- antimicrobials that either inhibit growth of or kill bacteria
Potential Approaches:
- development of “antimicrobials” that inhibit ____ formation,
plaque initiation, matrix biosynthesis and/or ____
- development of “antimicrobials that enhance ____ of
cells from the biofilm
mechanical
pellicle
quorum sensing
detachment
Determinants of the Microbial Microenvironment
____ never changes
With gingivitis: no change in position of alveolar bone/CEJ, what potentially can happen is ____ of junctional epithelium > now creates a microenvironement for formation of ____ plaque that is different from plaque that gave rise to gingivitis is growing; diamond: slight change in position of ____
With periodontitis: loss of ____ bone, remnants of JE, but it is positioned more ____ to where it was originally (clinical hallmark is loss of bone)
cementoenamel junction
apical migration
subgingival
JE
alveolar
apical
