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PER 1001 > Biofilm & Plaque Formation Pt. 2 > Flashcards

Biofilm & Plaque Formation Pt. 2 Flashcards

1
Q

When can colonizing bacteria be detected?

A

detected within 3 minutes after the introduction of sterile enamel into the mouth.

Immediately after introduction to oral cavity

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2
Q

When bacterial cells are in loose contact with the pellicle, what is important?

A

The proteins and carbohydrates that are exposed become important with this interaction

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3
Q

The specific interactions between microbial cell surface “adhesin” molecules and receptors in the salivary pellicle determine what?

A

whether a bacterial cell will remain associated with the surface.

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4
Q

What organims are the most abundant bacteria in biofilms on tooth enamel shortly after cleanings and why?

A

Only the relatively small proportion of oral bacteria possess adhesins that interact with receptors in the host pellicle

Adhesion ability of bacteria makes them specific to person

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5
Q

After the first 4-8 hours what genus of bacteria dominates in attachement?

A

genus Streptococcus
accounting for >20% of bacteria present.

+ obligate aerobes(nesseria) & faculative aerobes (actinomycyes & veillo

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6
Q

What 5 species are the primary colonizes of tooth surfaces

A
  1. Streptococcus spp.
  2. Haemophilus spp.
  3. Neisseria spp.
  4. Actinomyces spp.
  5. Veillonella spp.

Seek Help Not Attention it’s Vain

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7
Q

What do primary colonizers do for other bacteria?

A

Coadhesion
* provide new binding sites for adhesion by other oral bacteria.
* Metabolic ativity can inflience abolity of other bacteria to survive in dental plaque biofilm

eventually develop into biofil

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8
Q

Explain a metabolic way that primary colonizers of dental plaque help growth of obligate anerobes

A

byremoving oxygen, the primary colonizers provide conditions of low oxygen tension that permit the survival and growth of obligate anaerobes

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9
Q

What are the 3 phases of attachment of bacteria

A
  1. Transport to surface
  2. Inital Adhesion
  3. Strong attachment
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10
Q

Explain the 1st phase of bacterial attachment

A

transport of bacteria to the tooth surface
* Saliva flow and mechanical contact btwn oral soft tissue allow for primary colonizng bactera to contact teeth

most bacteria is not motile

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11
Q

Explain the 2nd phase of bacterial attachment

A

an initial reversible adhesion of the bacterium
* Bacteria comes in close contact w/surface 50nm
* Long and short range foces occur (van der wall attractive, and electorstatic repulsive)
* Van der wall result in net attraction of bacteral cell 10nm away from surface
* Stronger binding occurs via bacterial adhesions and receptors in the salivary pellice.

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12
Q

How many ligand-receptor interactions are required to attain essentially irreversible binding of a bacterial cell to the pellicle?

A

10-50 ligand receptor interactions

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13
Q

Explain the 3rd phase of bacterial attachment

A

firm anchorage between the bacterium and the surface is established.
* rough surface= bacterai more protected from forces that could displace them.

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14
Q

What is a specific quality of Capnocytophaga spp?

A

They prefer areas of high CO2 levels, found a little deeper.

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15
Q

Explain

A

primary colonizers
* Blue= gram + facultative anerobes
* Red= gram - anerobes

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16
Q

Secondary Colonnizers

A

**Gram - Anerobes / Facultative anerobes
Rods & spirochetes . **

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17
Q

Explain the relationship of S. gordonii and A. Oris

A

They coagreggate
* A .oris will only grow if you have S. gordoni with it. Bind to each other and aggregate

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18
Q

What complexes do primary colonizers come from?

A
  • Yellow (strep. spp)
  • Purple (a. odontolyticus
  • Blue (actinomyces spp)
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19
Q

What complexes do secondary colonizers come from?

A

Green, Orange, Red comeplexes

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20
Q

What are 3 spp. in green complex?

A
  1. Eikenella corroden
  2. Capnocytophaga spp.
  3. A. actinomycetemcomitans serotype a
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21
Q

What are 3 spp. in orange complex?

A
  1. Fusobacterium
  2. Prevotella
  3. Campylobacter spp.
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22
Q

what 2 complexes nclude species recognized as pathogens in periodontal and nonperiodontal infections.

A

Green and Orange complexes

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23
Q

3 Members of Red complex?

A
  1. T denticola
  2. P gingivalis
  3. T forsynthia
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24
Q

Explain this

A

Start with a plaque free subject with clinically non-inflamed ginigva
1. Plaque will slowly develope if all mechnical palque control is stopped
2. First few days= mostly gram + cocci & rods
3. Later on= shift toward gram - rods & filaments
4. Finally= Gram - spirochetes
5. Within few days mild ginigivities ensues
6. Once oral hygiene plaque control is restablihsed plaque composition returns to intila gram + situation and gingivitis dissapears

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25
Q

Where does dental plaque growth start?

A

areas that are protected from shear forces such as the
* gingival margin
* interdental space
* along grooves, cracks, pits, and fissures.

Plaque is stained red
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26
Q

Explain biofilm growth and planktonic growth and how it affects antimicrobial resistance

A

Planktonic grow suspended in liquid enviroment, while biofilm bacteria grow while attached to somthing.

The resistance of bacteria to antimicrobial agents is dramatically increased in the biofilm. 1000x more

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27
Q

What are some facors that affect resistance of bacteria to antibiotics?

A
  • Nutritional staus
  • Growth rate
  • temp
  • pH
  • Prior exposure to antimicrobial
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28
Q

What is an important mechanism of resitance of of biofilm bacteria?

A

slow growth rate
* makes them less susceptible to many but not all antibiotics.

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29
Q

Why is it hard for antibiotics to penetrate biofilms

A

Biofilm can act as an ion-exchange resin that removes the strongly charged/ chemically reactive agents of the antimicrobial= fail to reach deep zones.

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30
Q

What can happen to antimicrobial extracellular enzymes like
* β-lactamases
* formaldehyde lyase
* formaldehyde dehydrogenase
when they encounter a biofilm?

A

become trapped and concentrated in the extracellular matrix, and as such inactivate some antibiotics

positively charged hydrophilic antibiotics

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31
Q

What antibiotic is resitant to being traped in the extracellular matrix of biofilms and why?

A

Macrolides
* Positivley charged hydrophobic
* Uaffected by process!

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32
Q

Explain Supperresitant bacteria

A

These cells have multidrug resistance pumps that can extrude antimicrobial agents from the cell.

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33
Q

What do superessitant bacteria pumps specifcially do and target?

A

place the antibiotics outside of the outer membrane

  • all for resitance against antibiotics that targer cell wall synthesis
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34
Q

How does antibiotic resistance spread through a biofilm?

A

intercellular exchange of DNA

35
Q

consists of mineralized bacterial plaque that forms on the surfaces of natural teeth and dental prostheses

A

Calculus

can be seen on x-rays

36
Q

is located coronal to the gingival margin and therefore is visible in the oral cavity

A

Supragingival Calculus

37
Q

Explain color, consitancy, removal of supragingival calculus

A
  • Whute or whitish yellow
  • Hard, clay like consistency
  • Easily detachable from tooth surface BUT easily recurring.
  • Can be localized to a tooth or generalized
38
Q

Where is supragingival plaque most commonly reoccuring?

A

the lingual area of the mandibular incisors

39
Q

What influences the color of supragingival calculus?

A

Color influced with substances like tobacco and food pigments.

40
Q

What is the fundamental cornerstone to tx of chronic periodontitis?

A

Mechanical removal of subgingival plaque and calculus

41
Q

locatedbelow the crest of the marginal gingiva and therefore is not visible on routine clinical examination

A

Subgingival plaque

42
Q

Explain color, consitancy, removal of subgingival calculus

A
  • Location and extent evalulated by instriment
  • Hard dense
  • Dark brow/ greenish
  • Firmly attached to tooth
43
Q

Explain relationship of sub and supra gingival calulus and they occurance

A

generally occur together, but one may be present without the other.

44
Q

What happens to the classification of subgingival calculus when gingival tissue receads?

A

subgingival calculus becomes exposedand is therefore reclassified as supragingival

Thus Supra calculus can be composed of both the initial supra calculus and previous sub calculus

45
Q

What can be noted after removal of subgingival palque and calculus?

A
  • Reduction in gingival inflammation + probing depth
  • Gain in clinical attachment of gingiva
46
Q

radiopaque projections that protrude into the interdental spaces
are what?

A

Highly calcified interproximal calculus deposites

*note that detection levels are inconsitant**

47
Q

Location of calculus does not indicate the what? and why?

A

does not indicate thebottom of the periodontal pocket
because
* most apical plaque is not sufficiently calcified to be visible on radiographs

48
Q

Explain general compostion of calculus

A

Inorganic= 70-90%
Organic= the rest

49
Q

What makes up the major inorganic component of calculus?

A
  • Calcium phosphate (7.6%)
  • Calcium carbonate
  • magnesium phosphate
  • carbon dioxide
    + other trace element

Similar to that of other calcified tissues in the body

50
Q

What hard tissue in the body has the most inorganic content?

A

Calculus! 70-90%

51
Q

What makes up the major organic component of calculus?

A

mixture of
* protein–polysaccharide complexes
* desquamated epithelial cells
* Leukocytes
* various types of microorganisms.

Carbs, Salivary protiens, lipids

**all present in salivary glycoprotien

52
Q

How does attachment manner of calculus affect ?

A

affect the relative ease or difficulty encountered during its removal

53
Q

What are the 4 modes of calculus attachment?

A
  1. Supra
  2. Sub
  3. Attachment by means of organic pellice
  4. Mechanical locking on to surface irregularties like caries lesion or reorbtion lacunae
54
Q

What does this picture depict?

A

Calculus attached to the pellicel on the enamel surface and the cementum.

55
Q

What does picture depict?

A

Calculus attached to enamel surface, just coronal to CEJ

56
Q

How is soft plaque harden into calculus?How long to calcify? Does this always occur?

A
  • Hardened by the precipitation of mineral salts, which usually starts between the 1st and 14th days of plaque formation
  • Calcification starts within 4-8 hrs
  • 50% minerlaized by 2 days, 60-90% in 12 days
  • BUT all plaque does not undergo calcification
  • microbes not always essential in formation
57
Q

Plaque that does not develop into calculus reaches a plateau of maximal mineral content within how many days?

A

2 days

58
Q

Does calculus contribute directly to gingival inflamation?

A

NO
It retains dental plaque which contributes to gingival inflammation.

Open room by tissue= BAD

59
Q

What is the primary source of mineralization for supragingival calculus

A

Saliva!

60
Q

What is the primary source of mineralization for subgingival calculus?

A

gingival crevicular fluid (GFC, transudate; albumin) furnishes the minerals for subgingival calculus

61
Q

Compare calcium content in calculus to that of saliva

A

Calcium in calculus is 2-20x higher than saliva

62
Q

What mineral is more critical in plaque mineralization and why?

A

Phosphorous!

Early plaque of heavy calculus formers contains more calcium, 3x more phosphorus, and less potassium than that of noncalculus formers,

63
Q

What does calcification of dental plaque entail?

A
  • Binding of calcium ions to carb-protien complex of organic matrix in plaque
  • precepitation of cyrstilline calcium phosphate salts
64
Q

Explain trend of crystalization location in calculus formation

A
  • 1st in intracellular matirx + bacterial surface
  • then within bacteria
65
Q

The calcification of supragingival plaque and the attached component of subgingival plaque begins where?

A

along the inner surface**adjacent to the tooth structure. **

66
Q

What do foci of calcification do?

A

increase in size and coalesce to form solid masses of calculus

67
Q

What is required for intital mineralizationt to occur?

A
  1. Calcium-phosphate supersaturation
  2. membran asc. components
  3. regulation of nuclear inhibitors
68
Q

What can sometimes accompaany calcification?

A
  • alterations in the bacterial content
  • staining qualities of the plaque.
69
Q

As calcification progesses what is the trend in bacteria content

A
  • number of filamentous bacteria increases
  • foci of calcification change from basophilic to eosinophilic (more acidic)
70
Q

groups that exhibit a positive periodic acid–Schiff reaction show what?

A

a reduction in the staining intensity

71
Q

What is the 1st theoretical mechanism by which plaque becomes mineralized

A
  1. Mineral precipitation results from a local rise in the degree of saturation of calcium and phosphate ions
72
Q

What factors can elevate the pH of saliva

A
  • Loss of CO2
  • Formation of amonioa by dental plaque bactera though protein breakdown during stagnation of saliva
73
Q

Explain the relationship of collodial protiens and calcium phosphate

A
  • Normally Colloidal proteins in saliva bind calcium and phosphate ions and maintain a supersaturated solution
  • When saliva stagnates, collodies settle, supersaturated state no longer maintained= precipitation of calcium phosphate salt.
74
Q

Enzymes like phosphatase and esterases released by dental plaque, epithelial cells, or bacteria can also do what?

A

precipitates calcium phosphate by hydrolyzing organic phosphates in saliva.

75
Q

What is the 2nd theoretical mechanism by which plaque becomes mineralized?

A

heterogeneous nucleation
Seeding agents induce small foci of calcification that enlarge and coalesce to form a calcified mass.

The carbohydrate–protein complexes may initiate calcification by removing calcium from the saliva (chelation) and binding with it to form nuclei that induce the subsequent deposition of minerals.

76
Q

Role of Microorganisms in the Mineralization of Calculus

Explain locational trend in minerlaization

A
  • Start extracellularly both gram +/-
  • But may also start intracelllarly
  • Filamentous organims can form intracellular apatite crystals
  • Mineralization spreads until matrix and bacteria are calcified
    **Bacterial plaque may actively participate in the mineralization of calculus by forming phosphatases, which change the pH of the plaque and induce mineralization **
77
Q

an accumulation of microorganisms, desquamated epithelial cells, leukocytes, and a mixture of salivary proteins and lipids, with few or no food particles;

A

Materia Alba
* No internal plattern
* Yelow-grayish soft white sticky
* less adhearent han dentlal plawur

78
Q

what is The irritating effect of materia alba on the gingiva is caused by what?

A

bacteria and their products

79
Q

Most food debris is ____ and cleared from the oral cavity by salivary flow and the mechanical action of the tongue, cheeks, and lips.

A

rapidly liquefied by bacterial enzymes

80
Q

Compare clearance of aqueous vs sticky substnaes in mouth

A

Aqueous cleared= 15 min
Sticky= more than 1hr to clear

81
Q

Pigmented deposits on the tooth surface are called?

A

Dental Stains

82
Q

Do stains cause inflammation?

A

NO! they are an aesthetic problem

83
Q

The use of tobacco products coffee, tea, certain mouthrinses, and pigments in foods can contribute to what?

A

Stain formation

84
Q

Explain how a rise pH can result in mineral precipitation of calcium and phosphate ions

A

Arise in saliva, pH causes precipitation of calcium phosphate, salt by lowering the precipitation constant

PER 1001 (9 decks)

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