Oral Micro: Oral Ecology & Bacterial Plaque Biofilm Development

Front 1

Biofilm

Back 1

-multi-cellular, multispecies complexes held together by linking polymers
-matrix-enclosed bacterial populations adherent to each other and/or to surfaces or interfaces
-as long as normal flora biofilm are fed well/maintained they generally cause little problem
-if fed improperly (too many sweets, no oral hygiene) disease follows

Front 2

Basic Biofilm Properties

Back 2

-cooperating and competing community of different microorganisms
-microorganisms are arranged in microcolonies
-microcolonies are surrounded & attached together by protective matrix
-w/in & b/w the microcolonies are differing environments
-microorganisms have simple communicating system

Front 3

Quarum Sensing

Why Important?

Back 3

-pre-ordaining organisms reach certian # --> make community decisions
-bacteria send out signals get enough in # to change as a group
-want to target for theurapeutics

Front 4

Dental Plaque Biofilm

Back 4

-plaque like a well cared lawn (weeds can grow)
-as plaque grows thicker = less permeable to O2 & saliva, higher [toxic products], [acids], [inflammatory bacterial components]
-supragingival = less aerobic, dominant bugs are still strep and actinomyces

Front 5

Increased Inflammatory products on gingival crevice causes...

Back 5

1. gingivitis
2. pseudopcket
3. real pocket w/ increased gram negative
4. deep pockets & loss of attachment = periodontal disease

Front 6

Normal Flora
Supplementary Flora
Transient Flora
Pathogens

Back 6

-is of value and well behaved
-minority of population generally act like normal flora
-microorganisms brought to area from somewhere else (difficult time colonizing and competing)
-overt disease

Front 7

Microbial Flora

Back 7

-indigenous flora: space, nutrition, pH, anti-microbial factors
-difficult to clear, biofilm anywhere, very defensive, re-colonize easily

Front 8

Roles of Normal Flora

Back 8

1. Competition - competes against more pathogenic for space
2. VitK - we absorb what they make
3. Immune stimuli - LPS -> Gut
4. Source of opportunists (major but not only)
5. Etiologic agents of caries, pulp infections, & chronic inflamm. perio disease

Front 9

Oral Bacterial Colonization

Back 9

1. in utero = sterile
2. birth = yeast & lactobacillus
-saliva: kisses, nursing >from tongue/mucosa
>strep salivarious & actinomyces
3. Teeth erupt - non-shedding surface
-strep. sanguis
4. 19-33 months **Strep Mutans
-change in diet (increase sucrose, care giver)

Front 10

How is oral stable "bug pool" subject to change?

Back 10

life changes:
-puberty
-leave home environment (diet change)
-major disease (diabetes, etc)

Front 11

C-Section vs. Vaginal Birth

Back 11

30%+ born via C-section
-vaginal births delayed strep mutans colonization ~1month compared to c section
-hypoth: prob due to competition
>might make difference in not colonized by yeast or lactobacillus (better at fighting off strep mutans)

Front 12

Where Bugs Hang-out:
1. Tongue Papilla & Crypts
2. As Teeth Emerge W/in Days
3. Acquired as 2nd Molars Erupt
4. What is the oral cavity mainly?

Back 12

1. S. Salivarius
-Veillonella
-Fusobacterium
-Actinomyces
2. S. Sanguis & Group
-hard surface "olympics" (competitive environment)
3. (19-33mths) Mutans Group
-sucrose
4. Gram + Strep >50%

Front 13

1. Relation bw bacteria colonizing vs. tooth eruption occurs.

2. Relation bw mother's flora vs. child's colonization?

3. What is the pioneer bacteria upon tooth eruption?

Back 13

1. sanguis & tooth erupt = linear

2. if mother's high strep mutans = child colonized earlier

3. strep sanguis

Front 14

When do these bacteria appear:
1. S. salivarius
2. S. sanguis
3. S. mutans
4. A. viscosus

Back 14

1. immediately @ birth (mother kisses child)
2. colon w/ 1st tooth eruption, until teeth removed (elderly - dentures)
3. colon w/ 2nd molars, until teeth removed
4. appears at puberty

Front 15

How mother can drop Strep. mutans?

Back 15

1. diet & brushing
2. clorahexidine
3) xylitol

Front 16

Oral Ecology

Back 16

-some strep such as mutans appear dependent on enamel surface for colonization, other salivarius are not
-oral bacterial species are not evenly distributed but rather find their own ecological niche

Front 17

What bacteria are typically found in...
1) supragingival
2) subgingival

Back 17

1. gram +
-S. salivarius, sanguis, mutans, lactobacillus, actinomyces

2. gram -
-fusobacterium
-treponema
-prevotella
-porphyromonas gingivalis
-actinobacillus a.
-veillonella

Front 18

Characteristic of Supragingival

Back 18

-mostly gram +
-cocci, branched rods
-facultative & some anaerobes
-carbs (fermented)
-firmly adhere to plaque
-caries & gingivitis

Front 19

Characteristic of Subgingival

Back 19

-mostly gram neg
-mostly rods and spirochetes
-mostly anaerobes & facultative
-proteins (crevicular fluid)
-adhere less pronounced w/ many motile forms (flagella)
-gingivitis and periodontitis

Front 20

What is the #1 colonizer in the oral cavity?

Back 20

multiple surface adhesion molecules expressed by strep species allow them to adhere to many substrates

Front 21

How to bacterial plaque biofilms grow?

Back 21

slowly and perpendicular to tooth surface in small micro-colonies
-bacteria not evenly spread, leads to pathologies on small areas
-tooth is like state of az and bacteria ppl, population like viewing cities from a plane

Front 22

How to build a plaque biofilm?

Back 22

-complex grouping of various bacteria species that adhere to 1 another, bacteria products, and salivary proteins
-as plaque matures -> excludes saliva, O2, & food sources (further away & doesn't wash away or buffer acid = dental caries)

Front 23

Gingivitis vs. Periodontal Disease

Back 23

effects of poor oral hygiene: not mowing the lawn
-gingivitis reversible
-perio damage irreversible
tooth -> ionic bond -> pellicle protein -> saliva -> gram + branch forms = insoluble gel barrier

Front 24

Describe Harold Loe's experiment...

Back 24

-subjects stopped brushing for 21 days, plaquue quantified and gingivits measured
-as time % of gram neg anaerobic increased & aerobic bacteria decrease
-increase in gingivitis as increase in gram neg.
-once oral hygiene resumed #s reverted to normal and the gingivitis reversed

Front 25

Plaque Food Chains

Back 25

-some bacterial end products provide substrate or conditions beneficial for other bacteria
Supragingival:
1. pioneer species: Strep
-dextrans (glue, holds biofilm)
2. actinomyces: hangers on
-lactate -> veillonella
-veillonella -> acetate and formate (for 5)
3. secondary feeders
4. Vigilante Flora
-bactericins, NH4, H2S
Subgingiva
5. Climax Community - Spirochetes
-fusobacteria, eubacteria, bacteriodes, peptococcus, peptostreptococcus
>release thiamine, putrescine, isobutyrate, CO2
>subgingival = asaccharolytic