Enamel caries Flashcards
what do you have to do in order to view caries clinically?
clean (plaque-free), dry teeth
what is the clinical appearance of caries?
- White spot lesion -> opaque due to demineralisation of apatite
- Matt appearance due to slight demineralisation of the aprismatic layer
demineralisation of enamel starts where? why?
the enamel sheaths as there is more space for plaque acids to penetrate and dissolve hydroxyapatite crystals
what is the mounting medium used to view teeth ground sections under microscope?
quinoline
quinoline can penetrate large spaces, what colour do these sections appear?
lighter
quinoline cant penetrate small spaces, what colour do these sections appear?
darker
unlike a radiograph, microscopes with quinoline show different zones in a carious lesion. what are they? 4
translucent zone
dark zone
body of lesion
surface zone
what colour does the translucent zone appear? why?
lighter as its only partially demineralised so has large pores in which quinoline can penetrate
what colour does the dark zone appear? why?
dark as more mineral lost so large pores (demineralisation) and small pores (remineralisation) which quinoline cant penetrate
which area is believed to be a zone for remineralisation?
dark zone
what colour does the body of lesion appear? why?
lighter due to large loss of apatite so lots of large pores which quinoline can penetrate
what colour is the surface zone? why?
highly mineralised so very little large pores and small pores
how many carious lesions form for occlusal fissure caries?
2
carious lesions follow the direction of what? why?
prisms as prism sheaths have spaces so are the weakest part
remember in occlusal fissure caries the lesion widens as it gets to the ADJ causing a bigger problem
