Periodontal Microbiology #4 Flashcards
Roughy how long does it take (without brushing) for the average person to get gingivitis?
14 days
There are more than ______ species of bacteria found in the mouth.
700 (most individuals has about 60)
What is a plaque biofilm?
Organized cooperating community of organisms with specific inter-bacterial and host-bacterial interactions. (not just one type of bacteria)
Is gingivitis only bacteria induced?
NO! viruses and fungi have been implicated too
You remove ____% of plaque when you brush?
40
What are the stages of plaque formation?
Pelllicle formation? Attachement Growth Maturation Ecological succession
What is the difference between rapid and slow attachers?
- Rapid have specialized methods of attachment structures (fimbriae)
- Slow attachers have no specific mechanism for attachment.
When does co-aggregation and co-adhesion occur?
During the growth stage!
_____ is cell-to-cell recognition of genetically distinct/different cell types.
Co-aggregation ** This is mediated by protein or glycoprotein receptors on one cell and carbohydrates on the other.
_____ is the interactions between suspended and already adhering micro-organisms.
Co-adhesion
What factors influence Co-adhesion?
Increase in Lactose = decrease in co-adhesion
Temperature = no co-adhesion greater than 37 degrees
What is the purpose of Co-aggregation?
To form clumps of bacteria that can attach to the pellicle.
* This is mediated by protein or glycoprotein receptors on one cell and carbohydrates on the other.
Describe what happens during the Maturation stage of biofilm formation.
- Increase in diversity
- Replication and matrix formation
- Ecological succession
What types of bacteria are Primary or Early colonizers?
Gram + and Gram -
Streptococci bind pellicle proteins from saliva
*Primary colonizers are associated with health!
What Types of bacteria are Secondary colonizers?
Gram Negative bridge species (F. Nucleatum Prolific coaggregator) bind to other bacteria
What types of bacteria are Tertiary colonizers?
Gram negative bacteria (prophromonas gingivalis)
What occurs environmentally when the biofilm increases in thickness?
- Difficulty in diffusion join and out of the biofilm
- An oxygen gradient develops
- Completely anaerobic (no oxygen) conditions emerge in the deeper layers which can lead to fermentation.
- Reverse gradients of fermentation products develop as a result of bacterial metabolism.
What is the nutritional source for supra gingival plaque?
Dietary products dissolved in saliva
What is the nutritional source for sub gingival plaque?
Blood and Periodontal tissues
The structure of the biofilm can be described as ________ + _________.
Micro-colonies (15-20% volume) + inter-bacterial matrix
What makes up the inter-bacterial matrix of the biofilm?
- Dead bacterial cells
- Saliva
- Gingival exudate
_______ are considered the backbone of the biofilm.
Exopolysaccharides
What are the 3 layers of a biofilm?
- Lower layer = dense layer of microbes w/ steep concentration gradient.
- Loose layer
- Fluid layer = nourishes the biofilm by molecular diffusion
How does the physical structure of plaque differ?
Shape of colonies depend on shear force exposure.
- Interproximal (Supra gingival) = towers or mushrooms due to low shear force.
- Buccal side of teeth (supra) = elongated colonies capable of oscillation and withstanding high shear force.
- Subgingival plaque is similar to supragingival plaque in structure.
