Etiology Flashcards
What are the 3 major factors of periodontal pathogenesis?
Environmental factors
Host factors
Microbial factors
The structurally and functionally organized, species-rich microbial biofilms that form on teeth
Dental plaque
What is the main etiology for periodontal disease and dental caries?
Dental plaque
•White cheeselike accumulation •A soft accumulation of salivary proteins, bacteria, desquamated epithelial cells, and food debris •No organized structure •Easily displaced with a water spray
Materia Alba
•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
Dental plaque
•Mineralized dental plaque forms the hard deposit •Generally covered by a layer of unmineralized dental plaque
Calculus
What accounts for 70% of plaque?
Water
What accounts for 70% of dry weight of plaque (30%)?
Microorgs
What accounts for 30% of dry weight of plaque (30%)?
INtracelluluar matrix
Organic component Dental Plaque Polysaccharides Proteins Glycoproteins Lipids
Inorganic component Calcium Phosphorous Other minerals Sodium Potassium Fluoride
Intracellular matrix
More than ___ distinct microbial species
can be identified with highly sensitive
molecular techniques
500
What is dental plaque?
A. It is a non organized structure with soft accumulation of salivary
proteins, bacteria, desquamated epithelial cells, and food debris.
B. It is the structurally and functionally organized, species‐rich
microbial biofilm that form on teeth.
C. It is the hard deposit on the teeth surface which can be formed
by the mineralization of the matrix of salivary glycoproteins and
bacterial products.
D. It is the ornamental tablet in commemoration of the contribution
of the dentistry.
B. It is the structurally and functionally organized, species‐rich
microbial biofilm that form on teeth.
______ plaque
Gram+ cocci and short rods
Aerobic environment
Slight diversity
Supragingival plaque
_____ plaque
Gram- rods and spirochete
Anaerobic environment
Great diversity
Subgingival plaque
What are the 3 steps of formation of dental plaque?
- Formation of Pellicle
- Initial colonization of bacteria
- Secondary colonization and plaque maturation
Adsorption of a conditioning film
- An organic material layer coated on all surfaces in
the oral cavity, including hard and soft tissues.
- Components derived from saliva and crevicular
fluid.
- Gram+ facultative microorganisms are involved
Initial stage of the development of the plaque
•Acquired pellicle:
What are the 5 bacterial species seen as primary colonizers?
- Streptococcus spp.
- Hemophilus spp.
- Neisseria spp.
- Actinomyces spp.
- Veillonella spp.
What are the 4 bacterial species seen as Secondary colonizers?
- Prevotella intermidia.
- Capnocytophaga spp.
- Fusobacterium nucleatum
- Porphyromonas gingivalis
- Secondary colonizers adhere to the bacteria that
are already in the plaque mass - A significant feature can be seen by naked eye
Coaggregation
- Through further colonization and growth of additional species - Quorum sensing: cell-cell signaling - Environment modification - metabolic interaction
Maturation
__________ results in bacterial resistance
Quorum sensing
Quorum sensing results in _______
bacterial resistance
- Direct relationship between the total amount of plaque and the amplitude of the pathogenic effect
- Concept inherited: Control of periodontal disease depends on control of plaque accumulation
- Standard of care: oral hygiene measures, non-surgical/ surgical debridement
- All plaque are not equally pathogenic
- Not all Gingivitis develop into destructive periodontitis
- Site specificity in the pattern of disease was demonstrated in some individuals with periodontitis
Non-specific plaque hypothesis
- The pathogenicity depends on the presence of or increase in specific microorganisms - A. Actinomicetemcomitans in localized aggresive periodontitis - Targeted treatment strategies aim to control or eliminate the particular pathogenic organisms
Specific plaque hypothesis
- Both the total amount of dental plaque and the specific microbial composition of plaque may contribute - Microbial homeostasis: the state of the dynamic equilibrium
Ecologic plaque hypothesis
What are the 3 pathogenic bacteria that play a large role in periodontal disease?
P. gingivalis
B. forsthus (T. forthysia)
T. denticola
Criteria for Identification of Periodontopathogens •Be routinely isolated from diseased individuals •Be grown in pure culture in lab •Produce a similar disease when inoculated into susceptible lab animals •Be recovered from lesions in a diseases lab animal
Kochs Postulates
Criteria for Identification of Periodontopathogens •Be associated with disease •Be eliminated or decreased in sites that demonstrate clinical resolution •Demonstrate a alteration in host cellular or immune response •Be capable of causing disease in experimental models •Demonstrate virulence factors
Socransky’s criteria
_____ bacteria
Association
-Increased in localized aggressive periodontitis
lesions. Some in chronic periodontitis
lesions.
Elimination
- Suppressed or eliminated in successful
therapy, can be found in recurrent lesions
Host response
-Increased serum and local antibody levels
Animal studies
-Capable of inducing disease in gnotobiotic
rats
Virulence factors
-Host tissue cell adherence and invasion,
leukotoxin, protease, collagenase,
epitheliotoxin, FIF, bone resorption inducing
factors
AA: A. Actinomycetemcomitans
______ bateria
Association
-Increased in periodontitis lesions, found
associated with the crevicular epithelium
Elimination
-Suppressed or eliminated in successful
therapy, can be found in recurrent lesions
Host response
-Increased systemic and local antibody levels
Animal studies
-Important in experimental mixed infections
Virulence factors
-Host tissue cell adherence and invasion,
trypsin-like enzyme, collagenase, fibrinolysis,
phospholipase A, endotoxin, gingipains,
factors that affect PMN function
Pg: P. gingivalis
(virulence factors)
• Bacterial products that promote tissue destruction:
lipopolysaccharides(LPS), leukotoxin, gingipains,
collagenase, protease
Toxins and enzymes
(virulence factors)
• Factors that promote
colonization: fimbria,
gingipains
Adhesins
(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: lipopolysaccharides(LPS)
Evading mechanisms
Bacteria of \_\_\_\_\_\_\_ Actinomyces spp. Capnocytophaga spp. Campylobacter spp. Streptococcus spp. Parvimonas micra Fusobacterium nucleatum Prevotella intermedia Treponema spp.
Gingivitis
Bacteria of \_\_\_\_\_\_\_\_: Specific Bacteria in Disease Aggregatibacter actinomycetemcomitans (Type b) Porphyromonas gingivalis Prevotella intermedia Parvimonas micra Fusobacterium nucleatum Tannerella forsythia Treponema denticola Spirochetes
Periodontitis
Bacteria of \_\_\_\_\_\_\_\_\_: Fusobacterium nucleatum Prevotella intermedia Treponema spp. Spirochetes
Necrotizing Periodontal DIsease
Bacteria Associated with ______ and _______
Prevotella intermedia
Capnocytophaga spp.
Pregnancy and Puberty
Bacteria in \_\_\_\_\_\_\_\_: Fusobacterium nucleatum Parvimonas micra Prevotella intermedia Porphyromonas gingivalis Spirochetes
Abscess of the Periodontium
Do the following characteristics describe healthy or disease state bacteria? Gram +ve Cocci Nonmotile Facultative anaerobes Fermenting
Health
Do the following characteristics describe healthy or disease state bacteria?
Gram -ve Rod Motile Obligate anaerobes Proteolytic
Disease
Which one is correct for the specific bacteria
observed in correlated periodontal disease?
A. In diseased sites, more gram positive, nonmotile cocci are
observed
B. In healthy sites, more orange and red complex bacteria are
observed
C. A. actinomycetemcomitans and P. gingivalis are highly related to
periodontitis
D. Capnocytophaga spp. is usually found in periodontal abscess
C. A. actinomycetemcomitans and P. gingivalis are highly related to
periodontitis
P. gingivalis is known as a notorious periodontal pathogen. Which complex of color does it belong to? A. Yellow complex B. Green complex C. Orange complex D. Red complex
D. Red complex
Periodontal pathogens are _______ but not readily ________
communicable; transmissible
