Caries Aetiology & Risk Flashcards
What is aetiology?
Study of the cause of disease
The development of caries requires what 4 things?
Time
Tooth - susceptible surface
Plaque (biofilm) - dysbiotic
Sugars
3 steps of the development of a carious lesion (overview)
Active caries process in biofilm (sugar dependant)
Bacterial acid (lactic) production
Demineralisation of tooth structure
Carious lesion
4 facts about caries
- Biochemical process within biofilm
- Sugar converted to acids by bacteria
- Dependant upon available sugars
- Can be modified with changes to biofilm and environment of biofilm
What is a carious lesion?
2things
Clinically detectable demineralisation
The effect of bacterial acids from caries process
Carious lesion can be halted if
Caries process is controlled
What can happen to the mineral in a carious lesion? 2things
Loose further mineral
Regain limited mineral
A carious lesion results in what kind of problems? 2things
Functional
Aesthetic
What is the specific plaque hypothesis?
Small number of specific organisms are responsible for all of the disease
What is the non-specific plaque hypothesis?
All organisms in the micro flora contribute to disease, the specific bacteria don’t matter, disease can be present in all biofilms
What is marsh’s ecological plaque hypothesis?
CARIOGENIC BACTERIA are UBIQUITOUS in plaque, but usually in CONCENTRATIONS TOO LOW to cause problems, UNLESS THERE IS A SHIFT IN THE BALANCE driven by LOCAL ENVIRONMENTAL CHANGE
What is the ecological caries hypothesis?
Environmental acidification is the driving force which makes bacteria adapt to the acidic environment and selects bacteria more likely to tolerate it and produce acids themselves - dysbiosis
What is dysbiosis? 4 things
Increased cariogenicity of the biofilm
Acid production increases
Biofilm more acidogenic/aciduric
Favours species that produce more acid
How does an increased cariogenic diet and low salivary flow cause disease? 4 (include bacteria)
Increased stress in system
Increased acid production
Environmental shift -> low pH
Ecological shift within plaque -> S. mutants, lactobacilli and bifidobacteria
What is this graph?
The ‘Stephan’ curve with snacking
What happens to the tooth if pH is below 5.5?
Favours demineralisations of hydroxyapatite crystals (mineral component of enamel and dentine)
What happens to the tooth if pH is above 5.5?
potential for remineralisation of the enamel
What is enamel caries?
Effect of plaque acids on the enamel
Enamel structure 4 things
Prismatic
85% apatite
12% water
3% protein
What does this picture show?
White spot lesion
Why does the enamel need to be clean and dry to detect and diagnose enamel carious lesions? 2
Carious lesions found under plaque
Increased contrast between healthy and unhealthy enamel
How does the dentine and pulp respond to an enamel lesion?
Filling tubules with mineral
Add tertiary dentine to wall the area of the lesion off
This image shows tertiary dentine added to wall off the area of the lesion
Dentine structure 3
Tubular
33% protein - 20% collagen
70% mineral
