32-Oral biological system + Oral ecology Flashcards
Ecology
The scientific study of interactions among organisms + their environment
such as interactions organims have w/each other + their abiotic environment
Ecosystem
- Composed of microbial communities living on specific sites surrounded by different physical + chemical elements
- Ecosystem produces ⇢ nutrients, niches + regulates fluxes of energy and matter in the environment
Niche
Describes how an organism responds to distribution of resources + competitors + how in turn it alters these same factors
It is a way of life of a species
Oral microflora
Community of organisms coexisting in oral cavity as 1° habitat
They colonise oral surfaces + communicated between each other via complex signalling processes
The body own defences maintain a balanced + healthy oral environment
Resident flora
Found in eco-niche
MOs are grouped according to unequal conditions of life
Functions:
- Digestion
- Nutrition
- Competition w/pathogenic microflora
Transient microflora
These microbes just pass through but can colonise the niche of resident microflora
Can persist for a long time
Opportunistic microbes
Can become opportunistic pathogens + cause disease
Endogenous microflora
Already present in body but in a dormant form
eg. Bacterial flora
Exogenous
MOs introduced in body from external world
Can be benign or pathogenic
Origin of microflora
Microflora ⇢ acquired from birth as newborns have no bacteria in their mouth
- Sources ⇢ Saliva, H2O, food
- Overtime these create a climax community
- Point of stability is reached w/ ⇡ biodiversity in oral cavity
- Children acquire resident flora from their mother ⇢ possess identical strains of bacteria (vertical transmission)
Formation of ecosystem
Development of a microbial community ⇢ comprises of an alternation of populations
- Colonisation of environment by pioneer species/1st microbial population
- They modify new site + make conditions more habitable for new microbial populations
- As new communities grow ⇢ process of alternation of populations continue until there are no available niches for new species to colonise in
Periods of formation of oral ecosystem
- Neonatal period ⇢ aerobes obtained from mother + environment (mostly C. Albicans)
- Before eruption period ⇢ Facultative anaerobes + anaerobes ⇢ Mainly streptococcus
- Teeth eruption ⇢ colonisation by S.mutans + S.sanguis ⇢ require non-epithelial surfaces for colonisation + persist until teeth are present
3. After eruption period
- Actinomyces
- Lactobacillus
- Veillonella
- C. Albicans
Pathogenicity of microflora
- Microflora is usually non-pathogenic + forms integral part of host
- Also contributes to body defence against pathogen = colonisation resistance
3 main genera of oral microflora:
- Streptococci
- Actinomyces
- Lactobacillus
Functions of microflora:
- Achieving colonisation resistance for less available niche by saturating them w/pre-existing resident flora
- Resident flora inhibits infections by creating unfavourable conditions for microbes
Oral surfaces
Microflora in mouth is distributes according to types of surfaces present:
- Mucosal surfaces
- Dental surfaces
Mucosal surfaces
Palate, Cheeks + tongue
Sites available
- Smooth exfoliating surfaces
- Epithelial cells
- Multi-species intracellular flora
Main MOs present
Mucosal surface
- S. Oralis + S, Sanguis
- Neisseria, Haemophilus + Veilonella
Tongue surface
- S. Salivarius + S. Mitis
- Veillonella, Pepto streptococcus, G+ + G-ve rods
