microbiology of periodontal disease 2 Flashcards
What is the etiology of gingivitis?
healthy tissues then with plaque and biofilm it goes to gingivitis
what are the stages in plaque formation?
formation of acquired pellicle
primary colonization by gram-positive facultative cocci and rods (streptococcus sanguis, Actinomyces spp.)
subsequent adherence of gram-negative, strictly anaerobic bacteria (fusobacterium nucleatum, prevotella intermedia)
more gram-negative strictly anaerobic bacteria colonize secondarily and contribute to an increased pathogenicity of the biofilm (Porphyromonas gingivalis, Capnocytophaga sp.)
What is supragingival plaque like?
plaque found at or above the gingival margin
stratified organization of a multilayered accumulation of bacterial morphotypes
what is subgingival plaque like?
plaque found below the gingival margin, between the tooth and the gingival pocket epithelium
in general the microbiota differs in composition from the supragingival plaque mainly at deep periodontal pocket
what is subgingival plaque like?
plaque found below the gingival margin, between the tooth and the gingival pocket epithelium
in general the microbiota differs in composition from the supragingival plaque mainly at deep periodontal pocket
what are the three zones of subgingival plaque biofilm ?
tooth attached plaque, unattached plaque, epithelium attached plaque
what happens with periodontitis as it goes from gingivitis to periodontitis?
plaque biofilm becomes more gram negative and anaerobic, epithelial attachment migrates apically, destruction of connective tissue, resoprtion - bone loss
lesion is no longer limited to gingival tissue. Bone and periodontal ligament fibers are damaged and destroyed. Host is overwhelmed by pathogenic insult and collateral damage from immune inflammatory response.
Host tissue is not replaced. Resolution results in changed architecture.
what did the specific plaque hypothesis basically state?
not all bacteria are cariogenic and pathogenic in the oral cavity
what are the robert koch’s postulates?
causative agent must be routinely isolated from diseased individuals
must be grown in pure culture in laboratory
must produce a similar disease when inoculated into susceptible laboratory animals
must be recovered from lesions in a diseased laboratory animal
what are sigmund socransky criteria for identification of periodontal pathogens?
must be associated with disease (increased numbers)
must be eliminated or decreased in sites that demonstrate clinical resolution of disease with treatment
must demonstrate a host response
must be capable of causing disease in experimental animal models
must demonstrate virulence factors responsible for enabling the microorganism to cause destruction of the periodontal tissues
what are the periodontal pathogens?
Aggregatibacter actinomycetemcomitans porphyromonas gingivalis tannerella forsythia spriochetes prevotella intermedia
what are the periodontal pathogens?
Aggregatibacter actinomycetemcomitans porphyromonas gingivalis tannerella forsythia spriochetes prevotella intermedia
For dental plaque-induced chronic gingivits what are the most common types?
gram-positive (56%)
gram-negative (44%)
facultative (59%) and anaerobic (41%)
predominant gram-positive include S. sanguis, mitis, intermedius, oralis, A. viscosus, naeslundii, and P. micros
gram-negative: F. nucleatum, P. intermedia, V. parvula, Campylobacter species
what is the microbiology of chronic periodontitis?
anaerobic (90%) and gram-negative (75%)
bacteria most often cultivated: P. gingivalis, T forsythia, P. intermedia, C. rectus, E. corrodens, F. nucleatum, A. actinomycetemcomitans, P. micros and Treponema and Eubacterium species
What is A. actinomycetemcomitans?
small short straight or curved rod with rounded ends
nonmotile and gram-negative
multiple biotypes and five serotypes (a to e) based on differences in polysaccharide composition
strains fro patients in Africa seem to have an increased leukotoxin production
