unit 25+26 ecology of the oral microbiota

ecology

study of the relationship between living organisms and their environment

organism

any living thing

environment

the surroundings of an organism

habitat

type of natural environment in which a particular species of organism live

ecosystem is composed of

microbial communities living on specific sites surrounded by different physical and chemical elements

oral microbiota is acquired from (what age)

from birth

do new-born babies have any bacteria

no

what happens to the oral cavity after birth

it becomes colonized by different strains of bacteria

the individual is also exposed to…….. of bacteria

external sources

……… of the oral cavity increases, to a point where …… is reached

biodiversity

stability

biodiversity of the oral cavity increases, to a point where stability is reached is called

climax community

the oral ecosystem mainly comes from the

saliva

(but also food and water)

when is the oral ecosystem consumed

within the first few hours of life

what is vertical transmission in the oral ecosystem

majority comes from their mothers

what is horizontal transmission in the oral ecosystem

children interact with their peers

Buccal mucosa and dorsum of the tongue

the ……. surface of the tongue is highly colonised

papillary

Buccal mucosa and dorsum of the tongue

why is the papillary surface of the tongue highly colonised

because of the safe refuge provided by the papillae

Buccal mucosa and dorsum of the tongue

what controls microbial load on mucosal surfaces

Epithelial desquamation

Buccal mucosa and dorsum of the tongue

what happens during epithelial desquamation

epithelial squames loaded with bacteria are dislodged and swallowed with resident bacteria

teeth

what accumulates on tooth surfaces to produce dental plaque biofilm

microbes and their metabolic products

teeth

how does the bacterial community vary on teeth

it depends on the tooth and exposure to the environment

teeth

what surfaces are more anaerobic

subgingival or supragingival surfaces

subgingival surfaces

crevicular epithelium and gingival crevice

what role do microbes in the gingival crevice play

they initiate and propagate gingival and periodontal disease

crevicular epithelium and gingival crevice

what does gingival crevicular fluid provide

essential nutrients for many obligate anaerobes

crevicular epithelium and gingival crevice

what helps maintain homeostasis in the crevicular microbiome

antibodies

lysosomes

lactoferrin

prosthodontic and orthodontic appliances

how can dental appliances affect oral health

they act as inanimate reservoirs of bacteria and yeasts

prosthodontic and orthodontic appliances

what can poor denture fitting and hygiene lead to

candida-associated denture stomatitis

anatomical factors

saliva

gingival crevicular fluid

antimicrobial agents and inhibitors

miscellaneous factors (ph, diet, antimicrobial therapy)

host defences

host genetics

nutrient of oral bacteria

these are factors that relate to what?

factors modulation microbial growth

what remnants of the host diet are available for oral microflora

sucrose and starch

what salivary constituents serve as resources for oral microbes

glycoproteins, mineral and vitamins

what does crevicular exudate provide

serum proteins and related chemicals, including breakdown products of haemoglobin

what does inflammation exudate in periodontal pockets supply

blood components such as haem (mainly for anaerobes)

how do epithelial cell components contribute to nutrition

by-products of desquamated epithelial cells may accumulate and serve as a source of nutrition

what gaseous environment do most oral microbes require

very low level of oxygen

what extracellular resources do microbes use

extracellular microbial products of neighbouring bacteria

what intracellular resources do microbes store

glycogen granules

what is the effect of producing inhibitory factors like bacteriocins and hydrogen peroxide ?

it affects the viability of invading microbes

how do metabolic end products influence invading microbes

they lower the ph and create unfavourable conditions for growth

what is the role of quorum sensing molecules ?

they maintain the quality and quantity of resident bacteria in biofilm and dissuade colonisation by invaders