Lecture from (9/14) Flashcards
What is the formula for periodontal disease?
pathogenic flora,
lack of beneficial bacteria,
and a susceptible host
Periodontal pathogens:
- aggregatibacter actinomycetemcomitans (AA)
- Porphyromonas gingivalis
- Prevotella intermedia
- Tannerella forsythia
- Fusobacterium nucleatum
- Peptostreptococcus micros
- Campylobacter rectus
Beneficial species:
- Actinomyces spp.
- Strep mitis
- Strep sanguis
- Capnocytophaga spp.
- V. parvula
What are some characteristics of a susceptible host?
- impaired neutrophils
- inadequate immune response
- LPS responsiveness
- AIDS
- Diabetes
- Smoking
- Drugs
Steps in plaque formation:
- pellicle formation
- attachment
pellicle formation
a thin, bacteria-free layer of salivary proteins attach to the tooth surface within minutes of a professional cleaning.
Attachment of bacteria:
Within hours, bacteria begin to attach to the out surface of the pellicle. (via fimbriae on bacteria)
Typically begins with beneficial bacteria
Supragingival plaque
- Coronal plaque
- Marginal plaque
*usually aerobic bacteria
2 types of subgingival plaque:
-attached plaque:
tooth, epithelium, connective tissue
-unattached
*
What is attached (tooth-associated) subgingival plaque, where is it attached?
the zone of subgingival plaque directly attached to the surface of the tooth or calculus in the sulcus and pocket.
What is unattached (epithelial) subgingival plaque?
- not directly attached to tooth.
- gram-negative, motile bacteria
- in direct contact with junctional and sulcular epithelium.
What types of bacteria are found in young supraginival plaque?
- Mainly gram positive cocci and rods.
- some gram negative cocci and rods.
What types of bacteria are found in aged supragingival plaque?
An increase in gram negative anaerobic bacteria.
Characteristics of supragingival plaque:
- 50% matrix
- mostly gram +
- Few motile bacteria
- Aerobic
- Mostly carb metabolism
Characteristics of subgingival plaque:
- little to no matrix
- mostly gram -
- Motile bacteria are common
- High anaerobic
- Mostly protein metabolism
Characteristics of tooth-associated sub-gingival plaque:
- gram +
- does not extend to the JE
- Associated with calc and root caries
Characteristics of epithelium-associated plaque:
- gram+ and gram-
- extends to JE
- may penetrate epithelium and CT
- associated with gingivitis and periodontitis
Bacteria with a very strong association with periodontal disease:
A.a.
P. Gingivalis
T. forsythia
Bacteria with a strong association with periodontal disease:
P. intermedia E. nodatum Treponema sp. Eubacterium sp. C. rectus
Bacteria with a moderate association with periodontal disease:
S. intermedium
F. nucleatum
E. corrodens
P. micros
Bacteria associated with Localized Aggressive Periodontitis (LAP):
A.a
P. intermedia
P. gingivalis
Bacteria associated with Acute Necrotizing Ulcerative Gingivitis:
P. intermedia
intermediate sized Spirochetes
What bacteria are associated with Refractory Disease:
T. forythia
P. gingivalis
P intermedia
C. recta
What bacteria are associated with chronic periodontitis?
P. gingivalis P. intermedia F. nucleatum A.a. C. recta T. forsythia Treonema spp. E. corrodens
HIV associated gingivitis:
Candida albicans P. gingivalis P. intermedia F. necleatum A.a. C. recta
What are the characteristics of Aggregatibacter actinomycetemcomitans (A.a.)
- small, non-motile
- gram negative
- facultative anaerobe
- saccharolytic
- coccobacillus
- small convew colonies with a “star shaped” center
What is A.a. commonly associated with?
-aggressive periodontitis
What is a unique ability of A.a?
Has the ability to invade host epithelial cells.
What are exotoxins?
extracellular substances produced by bacteria which are toxic to certain cells or tissues of the body.
examples: botulinum, tetanus, diphteria
What exotoxin does A.a. produce? What does it do?
Leukotoxin.
Kills PMNs and monocytes in blood and pocket.
What are endotoxins?
-
What is lipopolysaccharide (LPS)?
is a virulence factor associated with many gram-negative bugs.
LPS is an integral part of the outer membrane and is released with bacteria dies.
**Causes/promotes tissue damage.
What happens with LPS release?
- has cytotoxic effects
- complement activation
- bone resorption (direct or indirect)
Characteristics of Porphyomonas gingivalis:
- gram negative
- anaerobic
- non-motile
- asaccharolytic
- rod shaped (bacillus)
- “black pigmented bacteroides”
- *invades epithelial cells
- forms dark brown/black colonies
