Caries- Caries Aetiology (cause) and Risk Flashcards
wha are the 4 things the caries require ?
- time
- teeth- susceptible surface
- bactiera in the biofilm
- diet sugar - amount/ frequency/ type
what are the 3 properties of enamel ?
- highly mineralised/ acellular tissue
- made from calcium phosphate crystals
- resembles the mineral, hydroxyapatite
at what ph does bacteria metabolise sugars?
4.5-5.5
what corrolation does pH and solubility display
low pH increases solubility.
as pH increases the solubility decreases.
what are the key features of Dentine?
70:20% inorganic: organic material. + 10% water
elastic properties stop enamel from fracturing
what is regrowing of dentin called and what initiates this ?
dentinogenesis
odontoblasts of the pulp
what are the chatacteristic of the Pulp?
composed of soft connective tissue/ vasuclar/ lymphatic/ nervous tissue.
what type of cells are in the pulp?
defence
fibers
ground substances
fibroblasts/ undefferentiated mesenchymal cells (macrophages/ lymphocytes)- defence
collagen type 1 and 2
ground substance- rich in proteoglycans/ glycoproteins/ large amounts of water.
Define marsh’s ecological plaque hypothesis ?
Cariogenic bacteria are ubiquitous in plaque, but usually in concenetrations too low to cause problems unless there is a shift in balance driven by local environmental changes.
what does cavitation do ?
the break down of outer enamel makes it difficult to remove biofilm out of the cavity.
what role do streptococcus mutants play in caries formation ?
Streptococcus mutants colonise the dental surface and cause damage to the hard tooth structure in the presence of fermentable carbohydrates e.g., sucrose and fructose.
acid production
why does enamel look white and opaque when its clear ?
what happens when the refractive index is similar to another material like water ?
when the enamel crystals are affected they reflect light back to the surface.
the light is then allowed to pass through and transparency is restored. Therefore always dry the teeth to ensure u can see any caries formation.
what is the keep thing one must look for when applying bonding agent after acid etching ?
we must ensure that the tooth looks frosty to make certain that water in not filling the poors as this will not allow the bonding agent to work.
what are the most relevant acidogenic- aciduric baterial speicies known ?
Streptococcus mutants- iitiator
Bifidobacteria- enhancer
Lactobacillus- enhancer
what is the defining features of dental biofilm?
balanced popluation of microorganisms of low virulence and cariogenicity.
an increases in fermentable dietary carbohydrates changes this to high cariogenicity and increases organic acids
