4- etiology 2

What is the Socransky criteria? (5)

Associated with a disease- more pathogens at disease site

Eliminating pathogen should eliminate disease

Demonstrates a host response

Capable of causing disease in animal models

Demonstrates virulence factors

What are characteristics of periodontal disease?(identification, condition, etiology, importance of …)

Impossible to identify all bacterial species

Chronic condition combines continuous progression and outbreaks- asynchronous

Mixed bacterial etiology

Amount of pathogens more important than presence

How is periodontal disease a multifactorial disease?(reduced, complicated, strain, quality, ? or ?)

Has reduced specificity- just because a pathogen is present, doesn’t mean disease is

Complicated etiology- no standardised threshold of how much causes disease

Need genotype level to estimate strain

Quality of host response- hard to estimate

Endogenous or exogenous

How is the type and number of specific microorganisms that colonise something determined by?

The type and quantity of nutrients there are- so oral ecosystem is dynamic

What is the difference between allogeneic and autogenic succession?

When change in bacterial composition is determined by environmental change (abiotic) vs biotic factors, interactions between bacteria or virus

What is the difference in percentage of Gram + cocci and faculative bacilli vs gram - bacilli?

Healthy- 75, 13

Gingivitis- 44, 40

Periodontitis- 10-13, 74

When there is disease present, what can we see morphologically under a microscope?

Periodontal pathogens are immobile bacilli, fewer cocci

What are the 2 main factors that cause periodontal disease?

Host susceptibility

Presence of pathogenic bacteria

What are some factors of host susceptibility?

Partially genetic- link between genetic markers- increased interleukin 1

Influenced by environment- smoking, stress, diabetes- reciprocal relationship

Why do smokers suffer worse than healthier individuals with periodontal disease?

Have lower igg2 serum levels and antibodies against actinomyces comitans

Have lower implant success, heal worse after periodontal and muco gingival therapy and tissue regeneration

Which virus has been linked to higher incidence of chronic periodontitis and necrotising forms?

HIV

Changes host response to local subgingival microbiota

What are the key periodontal pathogens (Socranky red complex) and what are they related to?

Actinobacillus actinomycetemcomitans

Tannerella forsythia

Porphyromonas gingivalis

Treponema denticola

Periodontitis, unsuccessful therapy

If their concentration passes the threshold, which bacteria can cause periodontal disease? (Putative periodontal pathogens)

Prevotella intermedia and nigrescens

Campylobacter rectus

Fusobacetrium nucleatum

What are characteristics of Actinobacillus actinomycetemcomitans?

facultative anaerobic bacillus, non-mobile, gram negative

Role in progressive destructive periodontitis

Hard to eliminate, only with mechanical treatment

Genetic component

Large number of virulence factors- induce bone and ct destruction

What are characteristics of Porphyromonas gingivalis?

anaerobic bacillus, non-mobile, gram negative

Related to chronic periodontitis

Absent or small numbers in healthy sites, large in active

Virulence factors induce bone resorption, destruction of ct, inhibit host protection mechanisms

What are characteristics of tannerella forsythia?

Gram negative anaerobic bacillus

Pleomorphic

In subgingival plaque, deep pockets, aggressive periodontitis

What are characteristics of fusobacetrium nucleatum?

In adult periodontitis

Produces infections in other body parts

More when it progresses

What are characteristics of spirochaetes?

Anaerobic gram negative mobile helical

Common in pockets, can cause necrotising form

Indicator of treatment results- if present in healthy sites- high risk

How can some bacteria be beneficial?

Passively occupying a site that could be colonised by pathogens

Prevent pathogens ability to adhere and produce virulence factors

Affect pathogen growth

What is the evolution of periodontal diseases caused by?

Mixed infections

Composition of bacterial plaque differs among patients and locations within same patient

What is an example of a beneficial bacteria?

Streptococcus sangria- produces hydrogen peroxide

What viruses are related to periodontitis?

CMV, ebv, papilloma, herpes