Dental Caries IV Flashcards
tertiary dentin deposition occurs before caries____
reach dentine
describe the shape of caries progression in dentine :
cone shaped with base facing the enamel and apex facing the pulp
carious destruction of dentin involves:
1.)acid demineralization
2.)followed by proteolytic breakdown of matrix
how does irritation of odontoblasts (which results in reparative dentin secretion )happen if the reparative dentin is secreted before the caries ever reach the dentine ?
irritation is transmitted through weakened enamel (caries , attrition , erosion , abrasion , and restorative procedures)
list the events in the development of dentinal caries:
1.) acids softening of dentin (non-bacterial preactivation)
2.)widening of the dentinal tubules (demineralization)
3.) migration of pioneer bacteria along dentinal tubules
4.) expanding masses of bacteria
5.)distortion of dentinal tubules (beaded dentin )
6.) break down of interventing matrix
7.)liquifaction foci
8.) spread of bacterial infection in lateral dentinal tubules (transverse cleft)–> progressive disintegration of remaining matrix tissue
what are the 4 major zones of dentinal caries?
1.) zone of destruction (DEJ spred)
2.)zone of bacterial invasion
3.)zone of demineralization
4.)zone of sclerosis
what occludes the pulpal end of dead tracts ?
thin layer of hyaline calcified material derived from pulpal cells (eburnoid)
or
irregular reactionary dentin from differentiation of dodntoblasts
how does demineralization occur in dentin ( zone of demineralization)
acid from carious enamel diffuses into dentin–> decalcification of calls of tubules (non bacterial acid softening of dentin)
explain the first wave of bacterial invasion in dentin :
pioneer acidogenic bacteria (lactobacilli) produce acids which diffuse into the demineralized zone
what microorganisms are involved in the first wave of bacterial invasion ?
lactobacilli
explain the second wave of bacterial invasion of dentin :
mixed acidogenic and proteolytic organisms migrate extensively down the dentinal tubule , attacking the demineralized matrix
how do microorganisms in dentin continue producing acids when they have been cut off from their primary source of nutrition ?
prolytic microorganisms break down protein content of dentin
bacteria in adjacent tubules coalesce to form proteolytic areas called____
liquefaction foci (run parallel to the direction of the tubules
lesions at right angle to the course of the dentinal tubules containing bacteria are called:
transverse clefts
cavitation comenses from the___
DEJ
whats the difference between acute and chronic dentinal caries in apperance?
in acute rapidly progressing caries , necrotic dentin is soft and yellowish white. In chronic caries it has a brownish-black color and is of leathery consistency
tubules of tertiary dentin are:
irregular , tortuous, and fewer in number than in primary dentin or may be absent
root caries?:
-rapid demineralization
-followed by bacterial invasion along collagen fibers (sharpeys fibers , the takes the direction of the incremental lines
-saucer shaped
-spread laterally around root
early detection of caries (grading)
-chalky white apperance
0= no/slight changes in enamel translucency after prolonged drying
1=opacity hardly visible when wet but apparent whwn dried
2= oppacity visible without drying
3=localized enamel breakdown in opaque or discolored enamel and/or greyish discoloration from underlying enamel
4= cavitation of enamel exposing dentin
