Etiology Flashcards
what are the factors involved in periodontal pathogenesis
- environment factors
- microbial factors
- host factors
what bacteria lead to gingival inflammation
gram positive
gingival inflammation alters:
subgingival environment
what causes gingivitis
host immune and inflammatory reactions together with genetic predisposition and environmental influences able to contain infection
what causes periodontitis
host immune and inflammatory reactions together with genetic predisposition and environmental influences unable to contain infection
what is dental plaque
the structurally and functionally organized species rich microbial biofilms that form on teeth
dental plaque is the main etiologic agent for:
- periodontal diseases
- dental caries
describe materia alba and what is it made of
- white cheeselike accumulation
- a soft accumulation of salivary proteins, bacteria, desquamated epithelial cells and food debris
- no organized structure
- easily displaced with water spray
describe dental plaque
- resilient clear to yellow-grayish substance
- primarily composed of bacteria in a matrix of salivary glycoproteins and bacterial products
- considered to be a biofilm
- impossible to remove by rinsing or spraying
describe calculus
- mineralized dental plaque forms the hard deposit
- generally covered by a layer of unmineralized dental plaque
what is dental plaque composed of
- 70% water
- 70% microorganisms
- 30% intracellular matrix
what are the organic components of the intracellular matrix of dental plaque
- polysaccharides
- proteins
- glycoproteins
- lipids
what are the inorganic components in the intracellular matrix of dental plaque
- calcium
- phosphorus
- other minerals such as sodium, potassium, fluoride
1 gram of plaque contains approximately:
10^11 bacteria
more than ______ microbial species can be identified with highly sensitive molecular techniques
500
what are the sites of accumulation of dental plaque
- gingival thirds
- cracks, pits and fissures
- under overhanging restorations
- around malaligned teeth
what is the classification of dental plaque based on
the position on the tooth surface toward the gingival margin
what are the classifications of dental plaque
- supragingival plaque
- marginal plaque
- subgingival plaque
what are the types of subgingival plaque
- tooth attached plaque
- unattached plaque
- epithelial associated plaque
what type of bacteria are in supragingival plaque
gram positive cocci and short rods
what is the environment of supragingival plaque
- aerobic environment
- slight diversity
what is the environment and type of bacteria in subgingival plaque
- gram negative rods and spirochete
- anaerobic environment
- great diversity
what does supragingival plaque lead to
calculus formation and root caries
what does marginal plaque lead to
direct contact with gingival margin
- initiation and development of gingivitis
what does subgingival plaque lead to
tissue destruction
what are the steps for formation of dental plaque
step 1: formation of the pellicle
-step 2: initial colonization of bacteria
- step 3: secondary colonization and plaque maturation
what is the acquired pellicle formed by
adsorption of a conditioning film
what is the acquired pellicle
an organic material layer coated on all surfaces in the oral cavity including hard and soft tissues
acquired pellicle components are derived from:
saliva and crevicular fluid
what microbes are involved in the acquired pellicle
gram positive facultative microorganisms
how long does it take for the pellicle to form
1 minute
how is the pellicle formed
reversible adhesion between microbial cell surface (adhesins) and the conditioning film (receptors)
what does the reversible adhesion between microbial cell surface (adhesins) and the conditioning film (receptors) alter
the charge and the free energy of the surface which increases efficiency of the bacterial adhesion
how long does the reversible adhesion between microbial cell surface (adhesins) and the conditioning film (receptors) take
2 hours
what happens in initial colonization
adherence and coadhesion
what happens in initial colonization
- bacterial mass continue to grow
- alteration in the oxygen gradient, anaerobic conditions emerge in the deeper layers of the deposits
- there are primary colonizers to secondary colonizers
how long does initial colonization stage take
4-8 hours
what are the primary colonizers
- streptococcus spp.
- hemophilus spp.
- neisseria spp.
- actinomyces spp.
- veilonella spp.
what are the secondary colonizers
- prevotella intermedia.
- capnocytophaga spp.
- fusobacterium nucleatum
- porphyromonas gingivalis
what happens in colonization and maturation
- coaggregation
- maturation
how long does coaggregation
4-8 hours
what happens in coaggregation in plaque
- secondary colonizers adhere to the bacteria that are already in the plaque mass
- a significant feature can be seen by naked eye
what happens in maturation of plaque
- through further colonization and growth of additional species
- quorum sensing: cell-cell signaling
what does quorum sensing do
- environment modificatino
- metabolic interaction
how long does maturation of plaque take
12 hours
what is the structure of dental plaque
- open fluid filled channels running through plaque mass
- distinct microenvironment produced by matrix
- step chemical gradients for oxygen and pH
- quorum sensing results in bacterial resistance
what is corn cob formation
- coccal shaped cells attach along the tip of gram negative filamentous organisms
- an example of inter-bacterial adherence or coaggregation
what is the nonspecific plaque hypothesis
- direct relationship between the total amount of plaque and the amplitude of the pathogenic effect
- control of periodontal disease depends on control of plaque accumulation
- all plaque are not equally pathogenic
what is the standard of care in the nonspecific plaque hypothesis
oral hygiene measure, non- surgical/surgical debridement
what is meant by “all plaque are not equally pathogenic” in the nonspecific plaque hypothesis
- not all gingivitis develop into destructive periodontitis
- site specificity in the pattern of disease was demonstrated in some individuals with periodontitis
what is the specific plaque hypothesis
- the pathogenicity depends on the presence of or increase in specific microorganisms
- targeted treatment strategies aim to control or eliminate the particular pathogenic organisms
what specific organisms increases pathogenicity in the specific plaque hypothesis
A. actinomicetemcomitans
what is the ecologic plaque hypothesis
- both the total amount of dental plaque and the specific microbial composition of plaque may contribute
- microbial homeostasis: the stae of the dynamic equilibrium
what are Kochs postulates
- be routinely isolated from diseased individuals
- be grown in pure culture in lab
- produce similar disease when inoculated into susceptible animals
- be recovered from lesions in a diseased lab animal
what are the criteria for identification of periodontopathogens
- Kochs postulates
- Socransky’s criteria
what are Socransky’s criteria
- be associated with disease
- be eliminated or decreased in sites that demonstrate clinical resolution
- demonstrate an alteration in host cellular or immune response
- be capable of causing disease in experimental models
- demonstrate virulence factors
what is the association of A. actinomycetemcomitans
increased in localized aggressive periodontitis lesions, some in chronic periodontitis lesions
what is the elimination of A. actinomycetemcomitans
suppressed or eliminated in successful therapy, can be found in recurrent lesions
what is the host response to A. actinomycetemcomitans
increased serum and local antibody levels
what did the animal studies on A. actinomycetemcomitans show
capable of inducing disease in gnotobiotic
what are the virulence factors for A. actinomycetemcomitans
host tissue cell adherence and invasion and leukotoxin! - main ones
-protease, collagenase, epitheliotoxin, FIF, bone resorption inducing factors
what is the association for p. gingivalis
increased in periodontitis lesions, found associated with the crevicular epithelium
how is p. gingivalis eliminated
suppressed or eliminated in successful therapy, can be found in recurrent lesions
what is the host response to p. gingivalis
increased systemic and local antibody levels
what did the animal studies in p. gingivalis show
important in experimental mixed infections
what are the virulence factors of p. gingivalis
- host tissue cell adherence and invasion, endotoxin, gingipains- main ones!
- trypsin-like enzyme, collagenase, fibrinolysis, phospholipase A, factors that affect PMN function
what are the toxins and enzyme bacterial products that promote tissue destruction
- LPS
- leukotoxin
- gingipains
- collagenase
- protease
what are the adhesins and what do they do
- promote colonization
- fimbria
- gingipains
what are the evading mechanisms bacteria use as virulence factors
- the production of an extracellular capsule
- proteolytic degradation of host immunity components: gingipains
- modulate host response: bind serum components on bacterial cell surface
- invasion of gingival epithelial cells: LPS
what are the bacteria of gingivitis
- actinomyces spp.
- capnocytophaga spp.
- campylobacter spp.
- streptococcus spp.
- parvimonas micra
- fusobacterium nucleatum
- prevotella intermedia
- treponema spp.
what are the bacteria of periodontitis
- aggregatibacter actinomycetemcomitans (type B)
- porphyromonas gingivalis
- parvimonas micra
- fusobacteria nucleatum
- tannerella forsynthis
- treponema denticola
- spirochetes
what are the bacteria of necrotizing periodontal disease
- fusobacterium nucleatum
- prevotella intermedia
- treponema spp.
- spirochetes
what are the bacteria associated with pregnancy and puberty
- prevotella intermediia
- capnocytophaga spp.
what are the bacteria in abscess of the periodontium
- fusobacterium nucleatum
- parvimonas micra
- prevotella intermedia
- porphyromonas gingivalis
- spirochetes
what are the bacteria of peri-implantitis
comparable microbiota to that of periodontitis
what are the healthy bacteria
- gram positive
- cocci
-nonmotile - facultative anaerobes
- fermenting
what are the types of bacteria in disease
- gram negative
- rod
- motile
- obligate anaerobces
- proteolytic
what is the source of transmission of periodontal pathogens
saliva
what are the bacteria involed in the transmission of periodontal pathogens
- A-. actinomycetemcomitans
- p. gingivalis
what is the donor-recipient in the transmission of periodontal pathogens
- parent to child
- spouse to spouse
what percentage of transmission of periodontal pathogens between spouses
20-30%
is periodontal disease always the result in the transmission of periodontal pathogens from spouse to spouse
no
is there stronger bacterial transmission from spouse to spouse or parent to child
parent to child
