Lecture 11 & 12 Flashcards
Biofilm is made of a ___ matrix
polymeric
TF? Biofilm can adhere to both inert or living surfaces.
T
TF? All bacteria live in biofilm.
F. most
premedication is important for:
arificial heart valve, prosthetic limb, etc., , bacteria attach and grow, leading to failure and death
Why not just medicate IF colonization happens, instead of premedicating?
Much harder to break down after colonization
TF? Bacteria are methanogenic.
T
Benefit to bacteria of living in biofilm:
provides protection against environmental stressors
Bacteria found in biofilm is __ times more resistant to antibiotics than free bacteria.
1000
Biofilm growth sites:
hot tubs, ships, cooling pipes of power plant, oil pipelines
Biofilms on heart valves cause:
Endocarditis
Site of pseudomonas biofilm growth in IC people?
Alveoli
This bacteria can grow on tampons:
Strep
What bacteria grows in the biofilm of IC ppl?
pseudomonas
This bacteria can cause toxic shock:
Streptococci
___% of all infections in developed countries caused by biofilms:
65
Most common forms of oral disease:
Dental Caries and Periodontal Disease
The most common forms of oral disease are caused by:
Oral Biofilms
Steps in biofilm formation:
attachment, EPS and “irreversible” attachment, growth and maturation, dispersion of planktonic bacteria
Which is more similar to oral biofilm, coral reef or yogurt?
yogurt
TF Biofilms are homogenous.
F
How does water flow through biofilms?
channels
Fxn of water in biofilm:
Clear waste, bring nutrients, bacterial growth
bacteria in biofilm talk to each other via:
quorum sensing
This is a type of decision making process in bioilm:
quorum sensing
Quorum sensing:
decision-making process in biofilms, work together, more virulent, coordinate gene expression, form a multicellular organism, send signals and produce pathogenic molecules
TF? Biofilm is hard to kill with chlorhexidine.
T
What prevents the rinse from entering the biofilm to get to bacteria?
Matrix
Biofilms protect bacteria from both:
antiseptics and antimicrobials
Biofilm matrix:
restricts penetration of, and binds antimicrobials, reduces effective concentration, impairs phagocytic cells
TF? Free-living bacteria are harder to kill than bacteria in biofilm.
F. Bacteria in biofilm are harder to kill (100-1000 times harder)
How are bacteria id’ed in plaque and how many have been found?
nucleic acid technology, about 1000
Oral Biofilm is aka:
Dental plaque, sessile microbial communities, structured, yellow-grayish
All free-floating bacteria are:
planktonic
Does plaque develop on hard or soft tissue?
either
What is dental plaque made of?
Living and non living bacteria, their products, and salivary compounds
Dental plaque adheres stronger to (hard/soft) tissues
hard
TF? All bacteria in dental plaque are alive.
F. some alive, some dead
Primary colonizer of heart valve:
strep
Composition of dental plaque:
Microorganisms in bacterial polysaccharide matrix and salivary glycoproteins, sticky, impossible to remove by rinsing
There are more than ___ different bacterial species
in dental plaque.
800
How many bacteria are there per milligram wet weight in dental plaque?
> 10^10 (10 billion)
What, besides bacteria, is in dental plaque?
viruses, protozoa, yeast, and ameobas
Plaque Dry Weight:
70-80 % bacteria, 20-30 % intercellular matrix
The intercellular matrix of plaque is mainly:
bacterial products (glucans)
What are bacterial products?
glucans
TF? The composition of dental plaque is the same, whether it is sub- or supragingival.
F.
How does dental plaque differ in the mouth?
surpragingival vs. subgingival, healthy (ask, healthy plaque? Aerobic bacteria?) vs. diseased, different types of diseased tissues
What is the matrix of plaque composed of?
extracellular polysaccharide
TF? Materia alba is easily rinsed or sprayed away.
T
What is materia alba?
soft accumulations of bacteria and other material
What is calculus?
hard deposits
mineralized, plaque covered by plaque
Materia alba is (soft/hard), whereas calculus is (soft/hard).
soft, hard
TF? Supragingval plaque is associated with caries, but not gingivitis.
F. both
Different Kinds of Supragingival Plaque:
fissure, smooth surface, approximal
Where is fissure plaque found?
mainly in molar fissures
Where is msooth surface plaque found?
buccal and palatal surfaces
Where is approximal plaque found?
contact points of teeth
TF? All supragingival plaque produce acid and can lead to decalicification.
T
TF? Caries cause more plaque to accumulate.
T
When will improving OH alone not be sufficient to reduce the severity of gingivitis?
Many caries along the crevice
How long does the initial colonization take in the formation of dental plaque?
1-2 hours
What type of organisms are involved in the initial colonization in the formation of dental plaque?
aerobes, generally non-pathogenic, gram positive cocci and rods
List 3 early colonizeres:
S. sanguis, S. mutans, Act. viscosus
Is the attachment in the initial colonization reversible or irreversible?
reversible
Which attachment is irreversible.
the secondary, strong attachment
Which is stronger, the intial or the secondary attachement?
secondary
What increases the strength of the attachment in the formation of dental plaque over time?
Initial, weak attachement gets stronger as it produces extracellular matrix that binds them together
What type of bacteria are the pioneer species in the formation of dental plaque?
planktonic bacteria, within an hour
Are the primary colonizers GENERALLY pathogenic or non-pathogenic.
non-pathogenic
TF? Plaque can attach to tooth, epitelial tissue and ct, but not bone.
F. can attach to all of these surfaces or remain unattached
Subgingival plaque is associated with:
gingivitis and periodontitis
Subgingival plaque lays between the:
tooth and the sulcular / pocket epithelium
Plaque against tooth surface has different _____ than that along the epithelial surface.
receptors
TF? The bacteria found in deeper pockets is different than bacteria found in shallow pockets.
T
Why is supragingival plaque bacteria different than subgingival?
exposed to different nutrients and saliva, subgingival: more blood, less oxygen, more anaerobic
Serous fluid leaks out of ______.
crevicular lining
What part of hemin does P. gingivalis use?
protoporhorin, reduced oxygen tension, more anaeroebic the deeper the pocket
Supragingival plaque mainly thrives on:
polysaccharides, sacchrolytic
Will the presence of sugar help P. gingivalis to grow?
No
What are produced in deep pockets?
Proteolytic enzymes, immunoglobins cleave via proteases and use peptides for growth
Where does plaque formation start?
gingival margin and interdental spaces, areas protected against shear forces
In which direction does plaque formation extend?
coronally (ask, why do we specify coronally? It extends into the sulcus (apically) as well, right?)
Stages of Dental Plaque Formation:
deposition of pellicle, initial bacterial colonization, late bacterial colonization, maturation (DILM)
Via what structures do bacteria bind to other bacteria?
Pili, fibria (receptors), or lipopolysaccharide sugars
What is the first step in the formation of dental plaque?
deposition of pellicle
What is pellicle?
salivary glycoproteins, thin, microscopic coating of (ask, only the first, thin layer of plaque?)
How long does it take for pellicle to absorb to enamel?
seconds (we always have a pellicle layer on our teeth, R?)
What type of film is the pellicle?
conditioning film, amorphous, acellular
What is the second step in the formation of dental plaque?
initial colonization
Mechanisms of bacterial attachment:
hydrophobic interaction, calcium bridging (divalent ion), extracellular polysaccharide, surface appendages (Fimbria will bind sugars on proteins via adhesins)
calcium + bacteria may lead to:
clumping
To which portion of the tooth will bacterial attachment take place?
mineralized portion (? because Ca or P is required?) is this always via divalent calcium interaction?) ask
What is the third step in the formation of dental plaque?
late bacterial colonization
Late Bacterial Colonization:
Gram-positives multiply, secondary colonizers (ask, are all secondary colonoizers gram negative? yes) attach and multiply, subgingival colonization starts
When do secondary colonizers attach?
1-3 days later
To what do the secondary colonizers attach?
gram-positive species
TF? Secondary colonizers can also be primary colonizers.
F.
What type of bacteria are secondary colonizers?
Gram-negative cocci and rods, facultative and obligate anaerobes (pattern to attachment? Facultative first, closer to oxygen? Ask)
3 examples of secondary colonizers:
Fusobacterium nucleatum, Prevotella intermedia, Capnocytophaga species
What is the primary etiology for periodontal diseases?
subgingival colonization of dental plaque
What is the fourth step in the formation of dental plaque?
maturation
Maturation step in the formation of dental plaque:
increased plaque, tertiary colonizers, complex structure (i.e. Corn cob)
What type of bacteria are tertiary colonizers?
Gram negative bacteria
5 examples of tertiary colonizers in the formation of dental plaque:
Porphyromonas gingivalis, Campylobacter rectus, Eikenella corrodens, Aggregatibacter, actinomycetemcomitans, Oral spirochetes (should this include the red complex? denticola, forsythus, P. gingivalis?)
spirochetes are:
mobile bacteria
In which step of dental plaque formation do corn cob bacteria appear?
Step 4: maturation, “test-tube brushes” or “corn-cob” adherence of cocci to filaments
Timeline for dental plaque development:
0-2 days: thin biofilm, easily disrupted, 2-4 days: increase mass, 4-7 days: goes subgingivally, 7-11 days: increase diversity, 21+ days: biofilm mass - relative stability
Bacterial shifts in dental plaque formation:
Gram-positive cocci and rods –> Gram-negative cocci and rods –>
Filaments, fusobacteria, spirils and spirochaetes
What surrounds fluid channels of plaque?
bacterial microcolonies, intermicrobial matrix, and pellicle
Bacteria are surrounded by:
intercellular matrix
What is the intercellular matrix composed of?
Polysaccharides from bacterial metabolism
Minor components of intercellular matrix:
Salivary and serum proteins/glycoproteins
TF? The type of food consumed affects the type of bacteria present in the oral cavity.
T
Bacterial metabolism leads to the formation of:
polysaccharides
What complexes are mainly associated with peio disease?
Red and Orange Complex
Red complex bacteria:
P. gingivalis, T. forsythensis, T. denticola
Orange complex bacteria:
P. intermedia, nigrescens, and micros, F nuc. vincentii, nucleatum, polymorphum, and periodonticum, Outer: C. gracilis, C. rectus, E. nodatum, C. showae, S. consellatus
TF? Bacteria act as individual species
F. as microbial complexes
TF? Bacteria act as microbial complexes.
T
TF? Plaque causes gingivitis.
T
3 hypotheses related to plaque and oral disease:
non-specific, specific, and ecological plaque hypotheses
non-specific plaque hypothesis:
disease results from masses of plaque bacteria, “dirty mouth”
“Specific plaque hypothesis”:
disease results from certain species of plaque bacteria
“Ecological plaque hypothesis”:
changes in the environment “turn on” plaque bacteria to become ‘pathogenic’, no specific etiology, dynamic relationship between host and microbiota, increase biofilm, increase inflammatory response, alters local environment, selecting for more proteolytic microbes that lead to greater inflammation
Theories as to why stress can lead to more PD:
more steroids in body, not brushing as well due to stress
Tx for ecological plaque hypothesis:
remove biofilm and interfere with selective pressures
Effects of Metronidozol:
kills more anaerobic, gram negative than aerobic, gram positive
TF? Listerine and chlorhexidine kill bacteria non-selectively.
T
Therapeutic Implications for Plaque Hypotheses:
“Non-specific plaque hypothesis”: oral hygiene, “Specific plaque hypothesis”: antibiotics, vaccines, “Ecological plaque hypothesis”: diet, buffers, chelators, oxygen (environmental approaches)
Host defenses that influence oral microbiota:
temp, atmosphere, pH, genetics, health, lifestyle, receptors, nutrients, host defenses, microbial interactions
What does high crevicular fluid result in?
more food for proteolytic bacteria
Is there more or less tissue turnover with strong inflammation?
more
Will there be more bleeding with low or high gingival crevicular fluid (GCF) flow?
high
Will there be a low Eh, a raised pH and C with low or high gingival crevicular fluid (GCF) flow?
low
TF? The obligatory anaerobic biofilm is saccharolytic.
F. proteolytic
Most common biofilm diseases are:
periodontal disease and dental caries
How to reduce periodontal disease and dental caries
Daily removal of biofilm, periodic professional cleaning, frequency of recalls, determined by professional
Name of the explorer:
EXD: 11-12
Type of perio probe we use:
Michigan O (University of Michigan probe)
What type of calculus is the sickle scaler designed to remove?
supragingival calculus
How many straight cutting edges does the sickle scaler have?
2
The pointed tip of a sickle scaler:
toe
Use this primarily for mesial surfaces:
11/12
This can be used for BL and distal surfaces:
13/14
These tend to be more angled, 60-70 degree:
Graceys’ (single cutting edge)
These have two parallel cutting edges that converge:
curettes
Shape of scaler and curette in crossection
triangle, semicircle
Shape of the toe of a curette:
rounded
Angle of face for the universal curette:
90d to terminal shank
TF? The universal curette adapts to all four tooth surfaces
T
Angle of face for the area specific curette:
60- to 70-d to terminal shank, 1 cutting edge
How many surfaces can be cleaned with an area specific curette?
one
Which is is the cutting edge used in instrumentation for a curette?
the lower edge (i.e., the longer outer curved edge)
most versatile periodontal instrument:
curette
Curettes are designed for:
subgingival areas
Area-specific curettes are aka:
Gracey curettes
Angle fo the blade for Gracey curettes:
60-70d to the shank
Angle of shank in relation to blade for universal curettes:
90d
Chisel scaler is used for:
tenacious calculus- cutting edge beveled at 45d
Primary objective in sharpening a tool:
70-80 d internal angle of blade
Benefits of sharp instruments:
Better calculus removal with fewer strokes, smoother root surfaces, improved tactile sensitivity, requires less lateral pressure, increase control of strokes, and reduce clinician fatigue
Proper angle for sharpening:
100 to 110d angle,stone and face of blade
True or False? All primary colonized are non pathogenic.
F. Most
EPS stands for:
Extracellular polymeric substances
