Microbio Module 11

Front 1

Question 1: state how periodontal diseases are classified.

Back 1

- The rate of disease progress (chronic vs. aggressive)
- Lesion distribution (localized vs. generalized)
- Age Group
- Association with Systemic or Developmental Disorders

Front 2

Question 2: define
a) Localized aggressive periodontitis
b) Calculus
c) Chronic periodontitis

Back 2

a) Localized aggressive periodontitis
Localized (LAP), also termed juvenile periodontitis, which has onset at puberty and involves the incisors and first molars, with responses largely based on hyper-humoral (IgM, IgG, IgA) immune responses.

b) Calculus
Dental calculus is calcified dental plaque, composed primarily of calcium mineral salts deposited between and within the remains of formerly viable microbes.

c) Chronic periodontitis
Chronic periodontitis is the loss of connective tissue and alveolar bone support of the teeth that is the result of both the direct activity of pathogenic bacteria and plaque-induced inflammation.

Front 3

Question 3: name 3 diagnostic features of both chronic and aggressive periodontitis

Back 3

Chronic Periodontitis
Found mostly in adults
Presence of plaque and calculus - always extends into the cementum and are thicker than those associated with gingivitis.
Slow to moderate progression of tissue destruction - progression can be accentuated by diabetes or host conditions such smoking.
Filamentous Gram positive and Gram negative motile bacteria predominate.

Aggressive periodontitis
The severity of disease is not consistent with the occurrence of local factors such as plaque and calculus.
The progression of tissue destruction is rapid.
Genetic factors are involved
Alveolar bone may be damaged significantly
Not concurrent with systemic disease

Front 4

Question 4: describe the ecological plaque hypotheses

Back 4

The ecological plaque hypothesis has also been proposed and postulates the following process:
Inflammatory response to plaque accumulation,
Increased GCF flow provides nutrition to Gram negative anaerobes,
Gram negative anaerobes suppress other species leading to a population shift.
New Periodontopathic flora establishes a pathogenic consortium of microbes causing invasion and tissue destruction.

Front 5

Question 5: briefly describe periodontal microbe complexes

Back 5

Studies based on the detection of 40 different species in around 15,000 plaque samples identified 5 major bacterial complexes, where bacteria are found in association in different clinical conditions and plaque environments.

Front 6

Question 6: state at least 4 species associated with sub-gingival plaque

Back 6

Porphyromonas gingivalis,
P. intermedia,
Spirochetes,
Tannerella forsythia

Front 7

Question 7: give an overview of how antibodies both promote and prevent periodontal disease.

Back 7

Neutrophils are the major host defence
But it can destroy tissues with lysozymes

Ab opsonises and promotes phagocytosis, complement, agglutination
But it can also attract neutrophils to destroy tissues

Front 8

Question 8: describe immune complex reactions and hypersensitivity in periodontal disease.

Back 8

Anaphylactic reaction (type I):

- IgE antibody on basophils and mast cells bind with antigens and histamine,prostaglandins and other effectors are released.
- Localized, respiratory, GI, systemic, or shock.

Cytotoxic reaction (type II):
- Activation of complement and lysis of RBC (main Ab involved IgM).
- ABO Blood groupings are based on antigens on RBC surface.
- O (no) antigen, A antigen, B antigen, AB antigens.
- Involves Drugs (haptens) binding to RBC and inducing Ab against them.

Immune complex reaction (type III):
Immune complexes are too large to be phagocytised. Instead of being removed by phagocytes, they attach to the basement membrane of blood vessels attracting neutrophils, complement proteins. Neutrohpils destroy the tissues.

Cell mediated reactions (type IV, delayed hypersensitivity):
- Involves T cells – Td, delayed hypersensitivity T cells via activation of memory cells, involved in skin reactions. Also called contact allergy.

Front 9

Question 1: Define Dentoalveolar infections.

Back 9

Dentoalveolar infections are defined as pus-producing (pyogenic) infections associated with the teeth and supporting structures such as the periodontium (i.e. gingivae, periodontal ligament, cementum, and alveolar bone). (Lecture A).

Front 10

Question 2: Name 4 factors affecting the kinds of bacteria isolated from root canal infections.

Back 10

- Extension of caries
- Mechanical Exposure
- Trauma
- Association with periodontal disease

Front 11

Question 3: State what virulence factors are essential for opportunistic pathogens in the oral cavity to cause endodontic disease.

Back 11

Infections of the pulp are almost always secondary to other tooth infections. The bacteria associated with pulp infections are typically endogenous oral microbes, which simply gain access to the pulp tissue (ie dental caries). These microbes do not express virulence factors such as invasins, or toxins, and it is only bacterial growth in the rich nutrient environment of the pulp that causes inflammation and damage.
Therefore, the characteristics of dental caries causing bacteria (ie adhesion to tooth surface, demineralisation of hard tissues with acidic metabolic products, formation of biofilm/plaque) are essential in causing endodontic disease.

Front 12

Question 4: Define 4 key elements to managing endodontic infections.

Back 12

The primary treatment of endodontic infections is to establish and maintain surgical drainage and to remove the cause of infection.
Maintaining drainage in combination with antibiotics is the correct treatment.
Without adequate local drainage, fatal brain abscesses are possible.
Persistent pain is indicative of a continued need for drainage. Apical healing can take months.

Front 13

Question 6: Name 6 species commonly isolated from root canal infections.

Back 13

bacteroides
prevotella
lactobacillus
streptococci
clostridium
fusobacterium

Front 14

Question 7: State how you would collect a clinical sample from a peri-apical abscess and how you would use this sample to determine the ideal treatment option for a patient.

Back 14

- Collection of pus by needle aspiration or after excision
- Aseptic technique
- Swabs are highly prone to contamination by saliva and dental plaque flora
Since most infections are due to strict anaerobes samples must be appropriately handled and dispatched

Once the pathogen is identified, specific antibacterials can be prescribed???

Front 15

Question 8: Give 4 possible clinical presentations of suppurative Osteomyelitis of the Jaws.

Back 15

Inflammation of the bone leads to venous stasis, ischemia and pus formation.
May cause soft-tissue abscesses on the oral mucosa.
Acute form-pain and fever
Chronic form-tenderness

Front 16

Question 9: Describe the affect of calcium hydroxide (in seals in endodontics) on oral microbes.

Back 16

high alkalinity to kill bacteria.