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Chapter 6 Biofilms and perio inf
Terms in this set (88)
plays an important role in the initiation and progression of carious lesions and periodontal diseases
are the simplest organisms and most are harmless
species of bacteria that are not harmful
pathogenic or virulent
species of bacteria capable of causing disease
single cell membrane wall stains purple
double cell membrane wall, more resistant to destruction, releases endotoxins when they die also stains red
require oxygen to survive
cannot live in presence of oxygen
can exist in presence or absence of oxygen
mobile until land and adhere to a surface
can attach to tooth surface or to each other
it has been estimated that more than ? of all bacteria on earth live as attached bacteria.
a living film, containing a well organized community of many species of bacteria as well as other organisms and debris that grows on any wet surface
bioforms can form in nature and can exist on any ? surface that is exposed to a bacteria-containing fluid
attachment, growth and detachment
3 stages in the life cycle of a biofilm?
how many different bacterial species and subspecies are capable of colonizing the mouth?
between 100 and 1000
how many bacteria can be cultured from one healthy sulci?
~75% of bacteria
% of bacteria found in healthy sites are gram+ facultative rods and cocci
~13 % of population
% of bacteria that is gram- rods in healthy sulci
most bacteria found in health are ?
are there periodontal pathogens found in healthy sulci?
how much bacteria can be cultured from an ind site associated with gingivitis
equal portions of gram+ and gram- bacteria
bacteria found in chronic gingivitis consists of almost?
gram- rods account for what % of bacteria found in gingivitis
bacteria that can be cultured from an ind site with periodontitis
comprise of about 74% bacteria ass with periodontitis
associated with high proportions of gram- and motile bacteria
strongly associated with aggressive periodontitis but has been implicated in chronic perio, but less freq and in lower #'s.
gingival CT and bone
Agg actin. is capable of evading normal host immune response and of destroying ?
non-motile and gram-
Agg actin is?
the most commonly detected species on or in the epithelial cells recovered from perio pockets and the risk of perio attachment loss is higher in adoloescents who are colonized by T. forsythia than those in whom the species is not detected
gram - and nonmotile
tannerella forsythia is?
found in low #'s in health or gingivitis but more freq detected in aggressive forms of periodontits, in patients exhibiting perio disease progression, in sites that exhibit recurrance of disease of disease or in deep pockets that persist afte perio therapy.
induce an elevated host response in periodontits
P. gingivalis can inhibit migration of leukocytes across an epithelial barrier and?
periodontal disease is a ? infection caused by multiple bacteria!
perio pathogens are ? can be transferred from oral cavity of one person to another and kissing is the primary means by which saliva/bacteria is transmitted
phase 1: film coating
within min after tooth cleaning, a thin transparent bacteria-free coating the acquired pellicle forms
salivary glycoproteins and antibodies
acquired pellicle is composed of? It adheres to tooth surfaces, calculus,restorative materials and dental prosthesis
-protects enamel from acid attacks
-serves as a lubricant for tooth surfaces
-alters the charge and energy of the tooth suface, faciliatating bacterial adhesion
-mode of attachment for calculus
-able to reform within min of its removal
sig of the aquired pellicle
sicky surface that adheres to tooth on one side and provides a sticky surface on other side that facilitates bacterial attachment to tooth
serves as a nutrient source for bacteria and influences their colonization on tooth
features of acquired pellicle
Phase 2: initial attachment of bacteria to pellicle
bacteria begin to attach to outer surface of pellicle a few hours after its formation, bacteria attach with hair-like structures called fimbriae
phase 3: new bacteria join in
attached bacteria begin to produce substances that stimulate other free-floating bacteria to join the community(start mult)
phase 4: extracelluluar slime layer and microcolony formation
bacteria attaching to tooth surface stimulates bacteria to excrete a slimy, gluelike substance called the extracellular slime layer
-helps anchor bacteria to tooth and provides prot for attached bac
-once tooth surface covered with att bact, biofilm grows primarily through cell division of adherent bact
-proliferating bac begin to grow away from tooth
-bac blooms occur(specific species or groups grow at rapidly acc rates)
phase 5: mature biofilm: mushroom shaped microcolonies
bacteria cluster together to form mushroom-shaped microcolonies that are attached by a narrow base to the tooth surface
results in formation of complex coll of different bacteria linked together
each microcolony is a tiny indep comm containing? of compatible bacteria, different microcolonies may contain diff combo of bacteial species
may vary in co2 concentration, pH, and temp
environmental cond in each microcolony may ? this leads to a biodiversity that helps to ensure survivabliity of the biofilm in widely varying oral cond
shield protecting bacterial microcolonies
extracellular slime layer acts like? from antibiotics, antimicrobials and the bodys immune system
of saliva surround and influence shape of biofilm, can result in ext of biofilm that can break free and cell-to-cell collisions of bacteria facilitating exchange of genetic info among bact
form and penetrate extracellular slime layer and this directs fluids in and around biofilm bringing nutrients and O2 to bacteria and waste products away
chemical cell to cell comm and exchange of ? transfer among bacteria
produces signaling proteins that trigger adhesion of add bacteria and formation of extracellular slime layer
stacking one bacterial speiceies on top of another bac speicies
biofilm develops how?
cell to cell adherance of one bacterium to another. it is not random, each bac strain only has a limited set of bact to which they are able to adhere
rod shaped bacteria are surrounded by many cocci
gram- rods form in shape of bristles on a brush
first bact to colonize tooth are?
ealiest bact colonizers release ? that indicate cond are favorable for next group of bact to join biofim
free-floating bacteria ? biofilm until cond are favorable
intermediate and late colonizers
fusobacterium nucleatum, intermediate joiner then coaggregates with last colonizers
primary colonization (days 1-2)
a few hours after cleaning gram+ cocci adhere and penetrate into acquired pellicle
intermediate coaggregation(days 2-4)
gram+ cocci and rods coaggregate and mult, gram+ rods mult and outnumber cocci
coagreggaation of gram- bact(days 4-7)
gram - bact sucha s F. Nucleatum, Prevotella int. and other anerobic bact.
gram - bact coaggregate with gram +cocci and rods at gingival margin
plaque biofilm spreads coronally and it is dominated by cocci
diverse array of gram - organisms(days 14-21)
#'s and diversity of biofilm increase adn include large #'s of gram - bact and thrive in protected environment
mature plaque biofilm(days 14-21)
is very complex, gingivitis evident
disease causing potential of bacteria in a biofilm is much greater than in ind pathogenic species
blue, purple,yellow an green complexes
are early colonizers and thought to be compatinle with health
orange and red complexes
are comprised of speicies thought to be major etiologic agents of perio disease and are late colonizers
can free floating perio pathogens cause perio disease?
tooth surgace, pocket ep, or other bacteria attached to one of these surfaces
bacteria attaches to?
most pathogenic bacteria attaches to?
biofilm always have to reform from the beginning
biofilm adequately disrupted by daily self-care and rountine prof care has to ?
sequence of attachement
-acquired pellicle-early colonizers attach to tooth surface
-tooth surface covered in bact and biofilm begins to grow away from tooth forming a supragingival biofilm
by 3-12 weeks after supragingival plaque biofilm starts to form the subgingival biofilm is mature with predominately gram- anaerobic bact
as inflammation progresses the gingival margin becomes inflamed and swells and results in ? gingival enlargement, supragingival biofilm now subgingival biofilm
tooth associated plaque biofilm, tissue-associated plaque biofilm, and unattached bacteria
what are the 3 bacterial attacment zones?
tooth associated plaque biofilm
attached to tooth surface from ging margin almost to JE
subging bact appear to have ability to invade dentinal tubules of cementum if explosed
gram+ rods and cocci predominate
associated with calculus formation, root caries and root resporption
tissue associated plaque biofilm
-loosely attached to picket wall ep
-layers closest to soft tissue contain large #'s of spirochetes and flagellated bact, gram - cocci and rods also present
-bacteria can invade the gingival CT and lay on surface of alveolar bone
tissue associated plaque biofilm
most pathogenic of subgingival plaque
80% water, 20% organic and inorganic solids(with 70-80% being microorganisms
compostition of biofilm
organic solids in biofilm
primarily made up of carbs, proteins and lipids
Carbs-glucans,fructans, from dietary sucrose
proteins-supragingival(saliva), subgingival(gingival crevecular fluid)
inorganic solids in biofilm
calcium, phosphorus, magnesium, and flouride concentration are higher in biofilm than saliva with lingual of mand teeth having highest calcium and phosphorus
supragingival(gingivitis), subgingival(perio), pits and fissures of teeth and att gingiva and ext surfaces of oral ep
location of biofilm
heaviest and begins at ging margin, typically interproximal surfaces then going 1/3, middle 1/3 of tooth, least seen on lingual of max teeth
surface for biofilm to be on
the bodys immune response to plaque biofilm(host response)
primary cause of perio destruction
bacterial virulence factors
minor cause of perio dest
short amino acid chains found in living bact cell walls that control transport of mol in and out. T cells can ID the peptides lock into the peptide and then alert the rest of the immune system to the bacterial invader
lipopolysaccharides making up gram- cell membranes are released when bacteria are killed
harmful proteins released by bacteria that act on host tissues at a distance
cytotoxic agents harmful to host cells
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