Host defences against microbial plaque Flashcards
1
Q
The balance between what 4 things prevents the formation of periodontal diseases?
A
- Presence of pathogen
- Absence of beneficial species
- Host response
- Conducive environment around the oral cavity
2
Q
What are the functions of the host defences?
A
- To keep bacteria out out of the periodontium
2. Destroy any foreign microbes which succeeded in entering the system
3
Q
What does plaque accumulation begin with?
A
Begins with pioneer species attach to the pellicle of a clean tooth surface
4
Q
What are the stages of plaque formation
A
- Pioneer species attach to the pellicle surface of a clean tooth
- These multiply to form micro colonies
- Resulting in confluent growth of biofilm
- This increases species diversity
5
Q
Name the 5 things that help defend us from plaque
A
- Saliva
- Gingival epithelium
- Inflammation
- Immune system
- Mediators
6
Q
What are the functions of saliva?
A
It has a washing effect
It is a vehicle for swallowing bacteria
It also has an antimicrobial effect
7
Q
Approx how many bacteria do we swallow?
A
10^8 bacteria in every mL of saliva we swallow
8
Q
Name some antimicrobial substances in saliva
A
- Peroxidase/ Hypothiocyanate
- Lysozyme/ Lactoferrin
- Antibodies (IgA)
9
Q
What occurs if there is a lack of saliva?
A
Xerostomia
10
Q
What are some factors that may cause Xerostomia?
A
- Patients who are out breathers
- Drugs/ alcohol
- Radiotherapy
- Patients who have had their salivary glands removed surgically
11
Q
What are people with xerostomia more susceptible?
A
Gingivitis
Cervical caries
12
Q
What is the gingival epithelium comprised of?
A
The oral gingival epithelium
The oral sulcular epithelium
The junctional epithelium
13
Q
Describe how the gingival epithelium provides a mechanical barrier
A
- Seals against bacterial
- Has keratinocytes
- Has langerhans cells
14
Q
What is the junctional epithelium permeable to?
A
- Bacterial products that need to go in
- Crevicular fluid and neutrophils that need to go out
- It becomes more permeable in disease
15
Q
Describe the junctional epithelium in periodontal health
A
Has an intact junctional epithelium
16
Q
Describe east happens to the junctional epithelium as periodontal health deteriorates
A
Junctional epithelium migrates apically
This eventually forms a pocket between the junctional epithelium and root surface
17
Q
What is associated with the formation of a pocket between the junctional epithelium and root surface
A
Loss of connective periodontal attachment and loss of alveolar bone
18
Q
What is inflammation?
A
It is a response of living tissue to injury and provides a rapid first line of defence
19
Q
What are the 2 types of inflammation?
A
- Acute
2. Chronic
20
Q
What is acute inflammation?
A
It is non specific and has both fluid and cellular components
21
Q
Describe chronic inflammation
A
It is slower to establish than acute inflammation §
22
Q
What are the functions of the inflammatory response?
A
- To dilute by increasing crevicular fluid
- To wall off the inflammatory cells
- Destroy the inflammatory cells and the damaging pathogens
23
Q
Describe the sources of the fluid response of inflammation
A
- Vasodilation
- Increased permeability of endothelial cells
- Fluid and plasma proteins are release into the tissues and through GCF
24
Q
What is the inflammatory exudate
A
plasma proteins like antibodies and compliment that are released into the tissues and through GCF
25
How many proteins are involved in the compliment system?
9
26
Why does the compliment system play an important role in the fluid response of inflammation?
1. It is responsible fro mass cells producing histamine
2. Chemotaxis for neutrophils
3. Responsible for lysis and inhibition of a few species off bacteria
4. Can lead to opsonisation for phagocytosis
27
What do we expect to see as the fluid response of inflammation is occurring ?
1. Increased crevicular fluid flow
2. Gingival erythema
3. Oedema and selling of the gingiva
28
Name the key components of the cellular response of inflammation
1. Neutrophils
| 2. Macrophages
29
Why are neutrophils important?
1. They form the first line of defence
2. They can prevent bacteria from entering the gingival crevice
3. They form a layer on the surface of plaque
30
Describe the function of neutrophils in response to UNATTACHED bacteria
1. They recognise and bind to bacteria
2. They perform phagocytosis
3. They produce antibacterial agents
4. They digest micro organisms
5. They expel remnants
6. Contributes to bystander damage
31
What can bystander damage cause?
A little bit of damage to the surrounding tissues
32
Describe the function of neutrophils in response to bacteria in the plaque matrix
1. Neutrophils attach to the plaque matrix
2. They secrete antibacterial enzymes
3. They kill bacteria
4. They dissolve the plaque matrix
5. Contributes to bystander damage
33
Name some antibacterial enzymes neutrophils secrete
1. Hydrogen peroxide
| 2. Hypochlorous acid
34
What is a recognised side effect to the host defence system?
Bystander damage
35
Where do macrophages develop?
They develop from monocytes in the blood
36
What do macrophages play an important role in?
Both immunity and inflammation
37
Where do macrophages emigrate too?
They emigrate to inflamed gingival tissue
| Few of them enter the gingival crevice
38
What role do macrophages have in inflammation?
1. Phagocytosis
2. Secrete tissue degrading enzymes
3. They secrete compliment components
4. They secrete mediators
39
Name some functions macrophages secrete in relation to inflammation
IL-1
TNF
Prostaglandins
40
Name some functions macrophages secrete in relation to immunity
1. They process and present antigens
| 2. They secrete IL-1
41
What type of inflammation is periodontal disease implicated by?
Both acute and chronic
42
What is gingivitis usually characterised by biochemically?
An increase in leukotriene B4 in the gingival crevicular fluid
43
What is leukotriene B4 a product of?
Degranulating neutrophils in the sulcus
44
What is periodontitis usually characterised by biochemically?
```
An increase in :
1. prostateglandin E2
2. IL-1 beta
3. tumour necrosis factor alpha
All three of these represent an activation of macrophages and lympohcytes within the tissue
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45
Describe the immune response
It is stimulus specific and has memory
It is initiated by antigens
Antigens are recognised by lymphocytes
46
What are the 2 aspects of the immune responses?
1. Humoral
| 2. Cell mediated
47
Which cells are involved in the humeral response?
B lymphocytes undergo differentiation to give:
1. Plasma cells
2. Immunoglobulins
48
Which cells are involved in the cell mediated response?
T lymphocytes there are 2 types:
| 1. T helper cells 2. T cytotoxic cells
49
What activates the humoral response?
1. Bacteria
2. Toxins
3. Other plaque antigens
50
What initiates the humoral response?
An antigen presented by the macrophages
51
Describe the humoral response
1. Antigen presented by the macrophages
2. B lymphocytes recognise foreign antigens and undergo clonal expansion
3. B lymphocytes differentiate into plasma cells under T lymphocytes are initiated
4. Antibodies are produced
52
What type of antibodies make up the majority of the humoral response?
IgG makes up 75% of the antibodies in the humoral response
53
Describe the antibody production in the saliva
1. Bacteria is swallowed in the saliva
2. Antigens recognised in the gut
3. IgA secreted into the saliva
54
Describe the antibody production in the gingiva
1. Antigens penetrate gingiva
2. Antigens carried to lymph node outside the ginigva
3. Antibodies IgG and IgM are secretes into the plasma pass to GCF
55
What are the 2 mechanism by which antibodies fight off antibodies?
1. Binding to the bacteria
| 2. Binding to the soluble factors secreted by the pathogens
56
Describe how the antibodies fight off pathogen by binding to the bacteria
1. Inhibits attachment
2. Opsonisation
3. Activating complement
4. Inhibiting metabolism
57
Describe how the antibodies fight off pathogen by binding to the soluble factors
Neutralising toxins
| Inhibiting enzymes
58
What does the cell mediated immune response regulate?
Regulates plasma cell differentiation
59
What are some defects in the host response?
1. Reduction in neutrophil number
| 2. Defective neutrophil function
60
What can a reduction in neutrophil number cause?
1. Cyclic neutropenia
2. Agranulocytosis
these can have a clinical effect on gingiva and periodontal tissues
61
Name some genetic conditions that can result in defective neutrophil function
```
Downs syndrome
Diabetes
Papillon- Levfevre syndrom
Chediak-Higashi syndrom
Leucocyte adhesion deficiency
```
62
What causes down syndrome?
Trisomy chromosome 21
63
What can be seen in SOME patients who have down syndrome
They can have advancing forms of periodontitis in both the primary and secondary dentitions
64
How can having Down syndrome increase you chances of having periodontitis?
There can be defects in the:
1. neutrophil chemotaxis
2. neutrophil Killing
3. phagocytosis
65
What can poorly controlled diabetes be associated with?
An increase in susceptibility to periodontitis
66
How can having uncontrolled diabetes increase you chances of having periodontitis?
1. Decreased neutrophil function
2. Decreased collagen synthesis
3. Increased collagenolytic activity
4. Increased periodontopathogens in sub gingival biofilm
67
How many people in the uk are affected by diabetes
1.8 million
68
How many people in the uk are affected by papillion-lefevre
1 in 4 million
69
What is papillion-lefevre syndrome associated with?
Palmer plantar keratosis which means the palms of the hands and feet are scaley
70
What is a key feature of papillion-lefevre syndrome?
Rapid and aggressive periodontal destruction
71
How can having uncontrolled diabetes increase you chances of having papillion-lefevre syndrome?
Defective neutrophil function
| Genetics
72
What can happen to your gums if you smoke?
1. Smoking disguises onset of many diseases
2. Associated with the rapid progression of periodontal diseases
3. Connective tissue loss
4. Periodontal pocketing
5. Alveolar bone loss
73
How does smoking make it harder to detect periodontal disease?
Gums look normal so it is harder to see the symptoms of periodontal disease
74
How many people suffering fro refractory periodontitis were smoker?
90%
75
How can smoking make it harder to treat a periodontitis sufferer?
Makes them resistant to treatment
| Means they have a poor response to non surgical and surgical therapy
76
How can smoking increase you chances of having periodontitis?
1. It inhibits the neutrophil function
2. Impaired neutrophil oxidative bursts
3. Reduced antibody number
4. Depressed number of helper lymphocytes
77
How can having HIV increase you chances of having periodontitis?
1. Reduction in number of t helper cells
78
What can some people suffering from advanced HIV / AIDS have?
Necrotising ulcerative periodontitis
79
Name some mediators?
1. Histamine
2. Bradykinin
3. Cytokines
4. Prostaglandins
5. Metalloproteinases
80
What are histamine and bradykinin associated with?
Vasodilation
| Increased vascular permeability
81
Describe Cytokines
They are soluble proteins
They are secreted by cells
They transmit signals
82
What do Cytokines co ordinate?
The inflammatory and immune response
83
Give examples of Cytokines
IL-1
| TNF
84
What is the role of Cytokines?
To amplify inflammatory response
85
How do Cytokines amplify the inflammatory response
1. They activate macrophages
2. Activate lymphocytes
3. Causes cells to release prostaglandins and more Cytokines
4. Causes endothelial cels and fibroblast proliferation
5. Causes fibroblasts to release collagenase
6. Indices bone resorption
86
What do Prostaglandins do?
1. They cause capillary dilation
2. Increase endothelial permeability
3. PGE2 causes bone resorption
87
What are Prostaglandins produced by
Produced from arachidonic acid in cell membranes of inflammatory cells
88
Give examples of
1. Collagenase
| 2. Gelatinase
89
What are metalloproteinases involved in?
Connective tissue destruction
90
What are metalloproteinases produced by?
Fibroblasts
Monocytes
Neutrophils
91
What are metalloproteinases induced by?
IL-1
92
What are the major regulators of immunoinflammatroy responses that categorise periodontitis?
Cytokines
Chemokine
Prostaglandins
93
What is bystander damage a prominent feature of?
Of chronic inflammatory disease
94
How can we identify risk patients
1. Medical history
2. Social history
3. . Family history
4. Smokers
5. Host response based diagnostics kits
95
What can we do once we have identified a high risk patient
Tailor treatment to the patients' needs
96
How can we tailer treatment to high risk patients
1. Liaison with there GP
2. Give the oral hygiene aids
3. Give them smoking advice
4. Be selective about our use of adjunctive antibiotics
5. Prognosis of periodontal surgery
6. Put into place regular supportive programmes are available for the patient
97
What do Cytokines, Chemokine ,Prostaglandins have a major role in
They are major regulators of immunoinflammatroy responses that categorise periodontitis
