Plaque mediated disease

Question 1

Where on the tooth do we find oral plaque

Answer 1

Occlusally - around the top

Buccally/ligually - on the side either on the tongue or gum side

Smooth surface plaque - around the tooth

Aproximal plaque - plaque between teeth

Fissure plaque - inside the dents in the tooth

Gingival crevise plaque - found on the gum margin

If the plaque is above the gum its called supraingival plaque and if its below its called subgingival plaque

Question 2

How do caries form

Answer 2

Initial phase is the “white spot”
Good news: The white spot is reversible at this stage
Some harder to reach areas are more vulnerable (molars)
The cavity is the last part of the process

Question 3

Why do caries form

Answer 3

Eating sugar
Low salivary flow
Low exposure to fluoride
Poor oral hygiene

Question 4

What actually is a dental plaque

Answer 4

A polymicrobial biofilm made up of a multitude of micro-organisms which stick to one another onto a base called the acquired pellecle

Question 5

What causes caries

Answer 5

Bacteria are involved in the formation of lesions on the basis of their FUNCTION (rather than their name)

Bacteria that are best at being acidoduric (can survive in acidic conditions) and acidogenic (produces acid from sugars (carbohydrates)) are:
mutans streptococci  (strepmutans) and lactobacilli

Question 6

What is the Ecological Plaque Hypothesis

Answer 6

A theory that explains the polymicrobial nature of caries
Explains how bacteria associated with disease can be present at healthy sites
Disease is a result of the shift in the balance of the resident microflora
This is in response to environmental conditions that move the environment away from the homeostasis

Question 7

Which factors move the homeostasis towards caries and periodontal disease respectively

Answer 7

Caries:
acidogenic/duric bacteria, lactobactilli, sugar, low pH (5.5 or less), reduced salivary flow

Periodontal disease:
Gram negative anaerobes
Increased GCF (saliva equivilant in gingivae)
Inflammation
Immune suppression

Question 8

Name the bacteria associated with a healthy oral pH level

Answer 8

s. oralis

s. sanguinis

Question 9

How do we break the break cycle leading to caries

Answer 9

Eat less sugar
Remove the cariogenic species with toothbrush or floss
Restore the immune system
Expose to flouride
Repair the enamel using fillings
Use antimicrobial agents

Question 10

What is periodontal disease

Answer 10

Disease of the supporting tissues of the tooth (the structures which support the tooth)

Question 11

What type of environment does the gingival crevis present

Answer 11

Anaerobic
Abundance of protein in the environment
Sometimes a hostile inflammatory response

Question 12

What fluid is found in the gingivae

Answer 12

The gingival crevicular fluid - full of proteins

Question 13

What types of bacteria do you see predominating in the mouth in health vs disease

Answer 13

Health - gram positive, facultative, saccharolytic biofilm

Disease - obligately anaerobic, proteolytic biofilm

Question 14

What are the 3 categories of the ecological plaque hypothesis

Answer 14

Host response
Environmental change
Ecological shift

Question 15

What are the 4 main periodontal disease categories

Answer 15

Gingival Diseases (least severe)
Chronic periodontitis
Necrotising periodontal disease
Aggressive periodontitis

Question 16

What characterises gingivitis

Answer 16

Reversible inflammation of the gums
Due to poor oral hygiene
Hormonal disturbance (like in pregnancy)
Drug therapies
Smokers (affect on the immune system, carcinogens etc
Is a pre-cursor for periodontal disease

Question 17

What characterises Chronic Periodontitis

Answer 17

Major cause of tooth loss (1/3 of adults have this condition)
In addition to gingivitis loss of tooth attachment occurs (irreversible)
Alveolar bone loss may also occur
This leads to increased depth and BOP (bleeding on probing - suggests inflamation and bacterial build up)

Question 18

Which bacteria causes periodontal disease

Answer 18

There are many bacteria but the most common are porphyromonas gingivalis, treponema denticola, tannerella forsythia
Preotella
fusobacterium

Question 19

Where do the disease causing bacterium come from

Answer 19

Its thought they originate on the tongue
Healthy gingivae VS periodontal disease – flora is very different
Some periodontopathogens can attach to the mucosa (back of the tongue) and have been isolated from the tongue biofilm. Reservoir?
Tongue piercings can be a hazard for periodontal disease

Question 20

What is Necrotizing Periodontal Disease

Answer 20

An underlying systemic infection
NUG - severe and painful – causes halitosis due to the breakdown of gum tissue
A true infection caused by the presence of spirochaetes and fusobacteria
It causes a grey pseudo-membrane on the gingivae

Question 21

What causes Aggressive Periodontitis

Answer 21

Rare condition that usually occurs in adolescents due to hormone changes(females)

Inherited condition? (neutrophil disorder)

Leads to a rapid loss of tooth attachment

Associated with high levels of Aggregatibacter actinomycetemcomitans (AA) which creates a very toxic leukotoxin

Treated using Tetracycline/metronidazole/amoxycillin (anaerobic)

Question 22

Give examples of other periodontal diseases (associated with patient groups)

Answer 22

Pregnancy Gingivitis (presence of steroid hormones in GCF)

Group A Streptococcal gingivitis (throat – gingivae)

Diabetes Gingivitis inflammation - impaired healing, may increase insulin resistance.

HIV periodontal disease. Characterised by the presence of unusual and opportunistic pathogens

Question 23

What is the cascade leading from plaque accumulation to a change in resident microflora in the mouth

Answer 23

Host Inflammatory Response

Flow of GCF Increases

Delivery of nutrients (haemoglobin etc)

Proteolytic bacteria proliferate due to increased nutriants

Local pH increases (more products of bacterial breakdown), redox reduces

Up-regulation of bacterial virulence factors

Question 24

What are the links between oral health and systemic health

Answer 24

There is an association between periodontal disease and poor general health:
Cardiovascular Disease
Respiratory Disease
Diabetes
Risk of premature labour 
Risk of low birth weight

Question 25

Why do we think there is a link between systemic and oral health

Answer 25

Generally, its been hypothesised that people who dont take care of their teeth also dont take care of their bodies.

There are also more scientific links such as the risk of inflammation related to gram negative species resulting in toxic metabolites and increased lipopolysaccharides (endo toxins which produce an immune response - pyrogenic)

Question 26

Why does the presence of bacteria in the mouth impact the rest of the body

Answer 26

The periodontium is vascular so inflammatory mediators can reach distant sites
eg Oral bacteria can enter the bloodstream
Eg streptococci can move to the heart and cause endocarditis
Eg Infectious atherosclerosis caused by bacteria causing plaques in the arteries causing hypertension
Eg Aspiration pneumonia caused by bacterium movement from the mouth to the lungs

This is a very active area of research