Periodontal microbiology Flashcards
What are the mucosal infections?
- Thrush
- Angular cheilitis
- Denture stomatitis
What are the periodontal infections?
- Gingivitis
- Periodontitis
What are the influences on the oral microflora?
- Host factors
- Diet
- Saliva
- Gingival crevicular fluid
- Microbial interactions
- Gaseous environment
What is meant by host factor influence on oral microflora?
- Systemic disease
- Antibiotic use
- Oral hygiene methods
What is included in diet influence on oral microflora?
- Chemical composition
- Physical consistency
- Frequency of intake
What is included in saliva influence on oral microflora?
- Flow rate
- pH balance
- Antimicrobial factors
What is included in gingival crevicular fluid influence on oral microflora?
- Antimicrobial components
- Humoral immunity
What is included in microbial interactions influence on oral microflora?
- Competition
- Co-operation
What is included in gaseous environment influence on oral microflora?
- Oxygen conc
What are the periodontal classifications?
- Gingivitis
- Chronic perio
- Aggressive perio
- Necrotising periodontal disease
- Peri-implantitis
What is included within active disease microbiologically and immunologically?
- Cytotoxins
- Proteinases
- LPS
- H2S
- Pathogenic bacteria
- Non-protective immune responses
- Disruption of tissue homestasis
What are host factors for development of periodontal disease?
- Smoking/tobacco use
- Genetics
- Pregnancy/puberty
- Systemic disease
- Nutrition
In a healthy tooth what bacteria is present within tooth pocket?
- Colonisation of normal oral flora
- Healthy gums (gingiva)
In tooth with gingivitis what is present within pocket?
- Proportion of periodontopathogenic bacteria increases
- Mild inflammation at edge of gum
In tooth with periodontitis what is present within pocket?
- High conc of periodontopathogenic bacteria
- Severe inflammation and pocket formation
- Degradation of soft and bone tissue
What are the development phases of bacteria?
- Naked surface with no bacteria
- Conditioning film with host salivary glycoproteins
- Linking film e.g. streptococcus
- Coaggregation, re-conditioning film e.g. Actinomyces and Streptococcus
- Accumulation, Shedding e.g. Actinomyces, Streptococcus and Fusobacterium
What type of bacteria is present in health, gingivitis and periodontitis?
Health = gram-positive aerobic
Gingivitis = on its way to gram-negative anaerobic
Periodontitis = Gram-negative anaerobic
How does the biofilm develop?
- Adhesion of bacteria
- Colonisation of bacteria
- Accumulation of different bacteria
- Creates a complex community
- Then dispersal of bacteria occurs
What bacteria is present in health?
- Oral streptococci,
- Actinomyces
- Fusobacterium
What bacteria is present in gingivitis?
- Actinomyces
- Prevotella intermedia
- Bacteroides
- Fusobacterium nucleatum
What bacteria is present in periodontitis?
- Porphyromonas gingivalis
- Prevotella intermedia
What is a commensal community compared to disease community?
Commensal has constraint and exclusion of pathogens
Disease has overgrowth of pathogens
How is a multi-species biofilm formed?
- Colonisations occurs through adhesion molecules
- Early colonisers of various streptococcal species bind to acquired pellicle
- Actinomyces and Veillonella species associate closely with Streptococcal species
- Form primary layer of bioflilm
- Intermediate colonisers like F. nucleatum adhere to primary complex members
- Pathogenic bacteria like P.gingivalis and A.actinomycetemcomitans bind to intermediate colonisers
- Forms multi-species biofilm
What is Porphyromonas gingivalis?
- Oral pathogen
- Gram-neg non-motile rod, strict anaerobe
- Black pigmented from iron accumulation from hemin
What are virulence factors ?
- Refer to the components or structure of microorganism that helps in establishment of disease of infection
What are some examples of virulence factors?
- Fimbriae adhesins
- Different proteases (Collagenase, fibrinolysin, phospholipase A, Phosophatases)
- Endotoxin (LPS)
- Capsular polysaccharides
- Tissue toxic metabolic by-products (hydrogen sulphide, ammonia, fatty acids)
What are gingipains for?
- Provide peptides from heme from nutrition
- Possess haemaglutanin (HagA) domains for attachment
- Activate matrix metalloproteases (MMP’s)
- RgpA (arginine specific)
- Kpg (lysine specific)
How do gingipains manipulate host defences?
- Degradation of innate receptors
- Degradation of cytokines IL-8 and ICAM-1
How does P.gingivalis cause bone resorption?
- Encounters saliva and salivary molecules
- Leads to subgingival colonisation and adaptation
- Production of proteases, toxins and toxic by-products in pocket
- Leads to disruption of innate immunity and tissue and bone homeostasis
