Plaque Biofilm (Final Review) Flashcards
A layer of living organisms that can attach to a solid object:
biofilm
Biofilm is:
- Composed of _____
- Encased within _____
- ______ in content
- Frequently contain ______
- microbial cells
- a matrix that acts as a barrier
- diverse
- microcolonies of bacterial cells
Surrounds the bacteria within the plaque biofilm (acts as a barrier):
Plaque matrix
The plaque matrix is composed of:
inorganic & organic components that originate from bacteria
The MAJOR components of plaque matrix:
Polysaccharides derived from bacterial metabolism of carbs
The MINOR components of plaque matrix:
salivary glycoproteins
List the organic components of biofilm:
- polysaccharides
- proteins
- lipid material
- glycoproteins
- DNA
List the inorganic components of biofilm:
- calcium
- phosphorus
- trace amounts of sodium, potassium & fluoride
Nonmineralized; naturally acquired biofilm that develops on teeth:
Dental plaque
Dental plaque is a ______ biofilm
multi-species
Sticky colorless film which constantly forms over teeth:
dental plaque
How may dental plaque be removed?
with mechanical force such as brushing or flossing
Supragingival plaque:
- The initial growth occurs:
- The later growth occurs:
- along gingival margins & interdental spaces
- further extension in the coronal direction
What does materia alba consist of?
- Salivary proteins
- bacteria
- desquamated epithelial cells
- disintegrating food debris
Plaque that becomes mineralized by calcium & phosphate salts from the saliva:
calculus
What components from saliva allow plaque to mineralize?
calcium & phosphate salts
_____ plays a major role in periodontitis because it keeps plaque close to gingival tissues & makes it difficult to remove the irritant
calculus
T/F: CALCULUS is NOT the irritant, PLAQUE IS
True
Can calculus be removed with a toothbrush or floss?
no- must be removed professionally
Mineralization of plaque starts in the _______ and eventually occurs within the _____
intercellular matrix; bacterial cell
Calculus is composed of _____% inorganic components & _____% organic components
70-90% inorganic
10-30% organic
What are the 4 main crystal forms of calculus?
- Hydroxyapatite (58%)
- Magnesium whitlockite (21%)
- Octacalcium phosphate (12%)
- Brushite (9%)
Mineralization starts between days _____ of plaque formation
1-14
T/F: All plaque eventually undergoes mineralization
False- all plaque does NOT undergo mineralization
What are the mineral sources that aid in the mineralization of calculus?
Supragingival: saliva
Subgingival: GCF & inflammatory exudate
The supragingival mineral source that aids in the mineralization of calculus:
saliva
The subgingival mineral source that aids in the mineralization of calculus:
GCF & Inflammatory exudate
Supragingival calculus is _____ to the gingival margin
coronal
Supragingival calculus is ____ in color
white or yellowish
Supragingival calculus derives minerals from:
the slaiva
Supragingival calculus is commonly found adjacent to:
salivary gland ducts
Approximately ____% of supragingival calculus is mineralized
30%
Subgingival calculus is located:
below the crest of marginal gingiva; not clinically visible
What is best for detecting subgingival calculus?
explorer & radiographs
Subgingival calculus derives minerals from:
inflammatory exudate
Describe the color of subgingival calculus:
dense, dark brown or black due to blood components and/or bacterial degradation
Subgingival calculus can be ____ & ____ to the tooth
tenacious & firmly attached
What percentage of subgingival calculus is mineralized?
approximately 60%
How does calculus form/attach to cementum?
- organic pellicle
- mechanical locking into surface irregularieies
- close adaptation to gentle depression or sloping amounts of unaltered cementum
- bacterial penetration into cementum surfaces
What are the phases of dental plaque accumulation?
- formation of pellicle on tooth surface
- initial adhesion/attachment of bacteria
- colonization/plaque maturation
Put the following phases of dental plaque accumulation in order:
-initial adhesion/attachment
-colonization/plaque maturation
-formation of pellicle on tooth surface
- formation of pellicle on tooth surface
- initial adhesion/attachment of bacteria
- colonization/plaque maturation
The formation of an acquired pellicle originates from the:
saliva
Within how long from being removed does an acquired pellicle begin to form?
within 1 min
The acquired pellicle is _____ in nature & consists primarily of _____
acellular; glycoproteins
Colonization of the acquired pellicle serves as a _____ for bacteria
nutrient
It takes approximately ____ for the acquired pellicle to develop into its condensed, mature form
7 days
The initial adhesion/attachment of bacteria to the acquired pellicle occurs:
as soon as the bacteria is introduced into the mouth
With the initial adhesion/attachment of bacteria to the acquired pellicle, primary colonizers provide:
binding sites for other bacteria
What are the three phases of bacterial colonization onto the acquired pellicle:
- transport to the surface
- initial reversible adhesion
- strong attachment
(TIS the season to colonize to this pellicle)
With maturation of the plaque, ______ occur because of bacteria attaching to primary colonizing bacteria
Coadhesions
With maturation of the plaque, coadhesions lead to growth of:
microcolonies & thus biofilm
List the following steps of plaque formation in order:
-maturation
-intiation adhesion
-pellicle formation
-dispersion
- pellicle formation
- initial adhesion
- maturation
- dispersion
List the four functions of the acquired pellicle:
- protection
- lubrication
- Nidus for bacteria
- aids in the attachment of calculus
Which of the four functions of the acquired pellicle is being described?
-Provides a barrier against acids, thus reducing dental caries attack
Protective
Which of the four functions of the acquired pellicle is being described?
-Keeps surface moist, prevents drying
Lubrication
Which of the four functions of the acquired pellicle is being described?
-Key role in the development of plaque
Nidus for bacteria
Stage 1 of biofilm formation:
pellicle formation
Stage 2 of biofilm formation:
bacterial colonization
Stage 3 of biofilm formation:
plaque maturation
What stage & day of biofilm formation is gingivitis clinically evident?
Stage 3- Plaque maturation; days 14-24
The initial colonizers of plaque formation:
Gram + aerobic & facultative organisms (actinomyces, streptococcus)
The secondary colonizers of plaque formation:
P. intermedia
P. gingivalis
Capnocytophaga
Spirochetes
Motile rods
Gram - anaerobic organisms
The secondary colonizers of dental plaque formation (P-intermedia, P-gingivalis, Capnocytophaga, Spirochetes, motile rods & gram negative anaerobic organisms) are the:
etiologic initiators of caries and periodontitis
Are the initial colonizers or secondary colonizers of bacterial species found in plaque the etiologic initiators of caries & periodontitis?
Secondary colonizers
When energy sources are introduced (sucrose) to the microganisms in the plaque biofilm, the microorganisms produce:
- acid
- intracellular polysaccharides
- extracellular polysaccharides
Factors affecting plaque accumulation include:
- mechanical removal
- availability of nutrients
- undisturbed environment
- interaction between bacteria & host response
T/F: Organisms in biofilm are 100x more resistant to antibiotics
False- 1000-1500x more resistant
What makes the bacterial species in a biofilm less susceptible to antibiotics?
slower rate of growth of bacterial species
How long does it take before plaque is clinically visible?
two days
T/F: Dental plaque is NOT a derivative of food debris
True
Summary:
- Plaque cannot be removed by spraying water
- As plaque matures it becomes resistant to mechanical removal
- biofilm forms in three stages
& matures within 14-24 days - as bacteria search for nutrients, they migrate subgingivally
- host defends itself via inflammatory response; gingivitis is initiated
