Zusammenfassung der Ressource
FACTORS AFFECTING CARIOUS LESIONS
- Caries begins in plaque stagnation areas
- Dynamic process
- Carious process begins in plaque bio-film
- A complex aggregation of microbes attached to surface
- 1st sign = white spot lesion
- BIOFILM
- An aggregation of microorganisms in which cells adhere to each other/surfaces
- community which work together and interact
- contains extracellular material which comes from bacteria or oral cavity
- INITIATION OF CARIOUS PROCESS
- 1-14 days for caries to form
- early caries lesions can arrest
- the pellicle forms on a susceptible surface
- bacterial colonisations: S.sanguinis+S.mitis 1st then S.mutans
- this is followed by micro colony formation
- after 1-14 days there is a shift from Streptococci to Actinomyces
- PLAQUE STAGNATION AREAS
- Occlusal, approximal surface
- Demineralisation of enamel
- this can lead to cavitation
- cavity formation is irreversible
- adjacent to partial dentures, or fillings with bad margins
- CARIOGENIC BACTERIA
- have to be acidogenic ie breakdown sugars to acid
- be able to produce and utilise intra/extra cellular polyssacharides
- has to be aciduric - like acidic conditions
- 3 THEORIES OFCARIES/PLAQUE
- SPECIFIC PLAQUE HYPOTHESIS
- 300 species of intra oral microbes but only specific num involved in caries
- hence we should be able to immunise
- NON-SPECIFIC PLAQUE HYPOTHESIS
- Caries results from activity of microbes in biofilm
- Hence all plaque should be removed
- ECOLOGICAL PLAQUE HYPOTHOSIS
- Plaque can accumulate on any surface
- Its consistency depends on environment eg sugars available
- So remove the plaque a decrease sugar intake
- STEPHANS CURVE
- Shows pH of plaque after glucose rinse
- amount and frequency of sugar dictates severity of caries
- Saliva washes away acid and buffers
- DENTINE CARIES
- 2 layers described by FUZAYAMA
- OUTER(INFECTED)ZONE: demineralised+infected
- INNER(AFFECTED)ZONE:advancing front of lesion
- dentine demineralised collagen fibres still intact