Lecture 5 Flashcards
what is the nonspecific plaque hypothesis?
plaque control important in perio treatment
all plaque bacteria considered bad
any accumulation of micro-organisms at or below the ginginval margin causes inflammation
what is the specific plaque hypothesis?
specific organisms in dental plaque are the etiological agents
microbial composition of disease sites different from healthy sites
local debridement and systemic antibiotics could control LAP
what are the prereqs for disease initiation and progression
the virulent perio pathogen- strains no species important in disease?, pathogen must express virulence factors, pathogen must be in the right location in the site (adjacent to epithelium, apical part of pocket)
local environment- colonization by beneficial species, effect of local regulon (subgingival environment
host susceptibility- HIV infection, diabetes, smoking
what does colonization entail?
adhesins on bacteria bind to host receptors- type 1, 4 collagen, sialic acid, galactosyl residues, bacteria have fimbrae, outer membrane proteins
coaggregation
nutrient utilization- veillonella uses lactate made by streptococci, campylocbacter uses formate made by selenomonas, porphyromonas uses hemin from blood in sulcus
competitive inhibition- bacteriocins, hydrogen peroxide production
how does the bacteria overcome host defenses
desquamation of epithelium- invade epithelium, bind to underlying cells
antibody prevent binding- igg and iga proteases, mimic host antigens
phagocytic cells- leukotoxin, nonlethal suppression of immune cells
what are periodontal pathogens like?
complex microbial profile
several uncultivated species
microbial complexes
