History and Science Biofilms Flashcards
Dental Plaque as a Biofilm
- ¡Dental plaque is an oral biofilm composed of ____bacteria per ____
- ¡Teeth form a unique surface in the human body
- ____
- ___
- ____
- ____ is key for plaque initiation
- ___________ remove ____ bacteria
¡Dental plaque is an oral biofilm composed of 108 bacteria per milligram
¡Teeth form a unique surface in the human body
§Non-shedding
§Fluid
§Non-sterile environment
¡Adherence is key for plaque initiation
§Saliva flow/shear forces remove planktonic bacteria
General Plaque Concepts
- ¡Supragingival plaque-forms_______
- ¡Subgingival plaque-forms_______
- ¡Calculus- plaque that becomes ____
- ___%_______________
- ____% ____________
- ¡Formation of plaque associated with_______
- ____ associated with ____
- _______associated____
¡Supragingival plaque-forms above gumline
¡Subgingival plaque-forms below gumline
¡Calculus- plaque that becomes calcified
§80% mineralized material
§20% organic material
¡Formation of plaque associated with oral diseases
§Caries associated with supra-gingival
§Gum diseases associated subgingival
Early studies of plaque composition
1683
Dental Plaque:
Healthy plaque:
white matter thick as if it were batter
Many animicules moving
Biggest sort: strong swif motion
2nd sort spun round like a top (much more in number)
Healthy Plaque
Antique plaque continued
He repeated observations on 2 old men who had never cleaned their teeth
Great company of animalcules
Biggest sort: bent body into curves on going fwd
Such enormous number that all water seemed to be alive
Gross
Germ Theories of Disease
1800’s
Microorganisms, which are too small to be seen without the aid of a microscope, can ____ ____ ___ and cause____ ____
•___ ____ ____
- •
___ ____ ___
- •Bacteria are associated with ___ ___
- _____of wounds improves ____
- Washing ___ and ____ before surgery is a good idea
- ___ and___ ______
___ _ ____
_____ _____ ____ of _____
___ ___ of ____
•“Micro-organisms of the human mouth: the __ and ___ diseases which are caused by then ” published ___
•
•
Microorganisms, which are too small to be seen without the aid of a microscope, can invade the body and cause certain diseases
•Joseph Jackson Lister
•Inventor of compound microscope
•
•Baron Joseph Lister
•Bacteria are associated with wound infections
•Disinfection of wounds improves healing
• Washing hands and instruments before surgery is a good idea
• Listerine and Listeria monocytogenes
•
•Willoughby D. Miller, DDS.
•Chemo-parasitic theory of caries
•Focal Theory of Infection
•“Micro-organisms of the human mouth: the local and general diseases which are caused by then ” published 1890
•
•
What changes occur in dental plaque to produce gingivitis?
People started to believe that plaque
But they thought that
___ matters ___ doesnt
People started to believe that plaque causes oral disease.
But they thought all microbes were bad and caused disease
They thought it type of bacteria didn’t batter, only number
Experimental Gingivitis Model
Start with
No __ ___ until ____ ____
Measure ___ and ___ of bacteria at ___ ___ using ___ ___
Once gingivitis develops, ___________
Continue to observe bacteria until
§
§
§Start with healthy individuals with no gingivitis
§
§No oral hygiene until gingivitis develops
§
§Measure number and type of bacteria at gingival margin, using Gram Stain
§
§Once gingivitis develops, return to standard oral hygiene measures
§
§Continue to observe bacteria until gingival health returns
Results from Experimental Gingivitis Study
- Gingivitis develops in ____ days
- Bacterial flora goes through ___ stages after cleaning stops
- ____ days :
- §Bacteria are mainly _________
- ___ ____
- ___ days:
- ___ days :
- ____ days :
- •After cleaning resumes
- §Health returns within _ days
- §Flora returns to mainly___
- §No ___, ____ bacteria§
- §
Gingivitis develops in 6-15 days
•Bacterial flora goes through 3 stages after cleaning stops
§1-2 days :
§Bacteria are mainly Gram-positive cocci
§few leukocytes
§2-6 days:
§Gram-positive cocci
§Long filamentous rods
§some leukocytes (WBC)
§6-15 days :
§Gram-positive cocci
§Long filamentous rods
§Spirochetes/vibrios (long and short motile, curved rods)
§Gram-negative rods
§gingival bleeding
§heavy leukocyte infiltration
§
•After cleaning resumes
§Health returns within 7 days
§Flora returns to mainly cocci
§No spirochetes, Gram-negative bacteria§
§
Modern Plaque Studies
- ¡The EGM study showed:
- §Early colonizers are mostly _________
- §Intermediate stage of _________
- §Late stage of mostly ________
- ¡Modern studies were done to determine ___ ___, ____ ____
- ¡Modern Molecular Microbiology
- ____ ____ ____ _____
- ____ ____
¡The EGM study showed:
§Early colonizers are mostly Gram positives, cocci
§Intermediate stage of long filamentous bacteria
§Late stage of mostly Gram negative bacteria
¡Modern studies were done to determine species involved, biofilm appearance
¡Modern Molecular Microbiology
§16S rDNA Direct sequencing
§Confocal Microscopy
16s rDNA analysis of DNA
- ¡Many oral bacteria can not be __________
- §Instead we detect them through ___
- ¡16s is a ribosomal sub-unit ___
- ¡Highly ___ at the ___ level
- ¡Surrounded by ___ ___ ___, allowing ___ of ___ ___ 16s genes in same sample
- ¡Used to identify over ____ species of bacteria in plaque
- ¡Most___ __ __ ____ ___
¡Many oral bacteria can not be cultured in the laboratory
§Instead we detect them through DNA
¡16s is a ribosomal sub-unit gene
¡Highly unique at the species level
¡Surrounded by highly conserved DNA, allowing PCR of many different 16s genes in same sample
¡Used to identify over 900 species of bacteria in plaque
¡Most accurate method to identify species
Species specific 16S region
Bacterial 16s DNA
How many species of bacteria are in the oral cavity?
1179
24% named
8% cultured but not named
68% cant be cultured
