Dental Caries IV

Question 1

tertiary dentin deposition occurs before caries____

Answer 1

reach dentine

Question 2

describe the shape of caries progression in dentine :

Answer 2

cone shaped with base facing the enamel and apex facing the pulp

Question 3

carious destruction of dentin involves:

Answer 3

1.)acid demineralization
2.)followed by proteolytic breakdown of matrix

Question 4

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 ?

Answer 4

irritation is transmitted through weakened enamel (caries , attrition , erosion , abrasion , and restorative procedures)

Question 5

list the events in the development of dentinal caries:

Answer 5

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

Question 6

what are the 4 major zones of dentinal caries?

Answer 6

1.) zone of destruction (DEJ spred)

2.)zone of bacterial invasion

3.)zone of demineralization

4.)zone of sclerosis

Question 7

what occludes the pulpal end of dead tracts ?

Answer 7

thin layer of hyaline calcified material derived from pulpal cells (eburnoid)

or

irregular reactionary dentin from differentiation of dodntoblasts

Question 8

how does demineralization occur in dentin ( zone of demineralization)

Answer 8

acid from carious enamel diffuses into dentin–> decalcification of calls of tubules (non bacterial acid softening of dentin)

Question 9

explain the first wave of bacterial invasion in dentin :

Answer 9

pioneer acidogenic bacteria (lactobacilli) produce acids which diffuse into the demineralized zone

Question 10

what microorganisms are involved in the first wave of bacterial invasion ?

Answer 10

lactobacilli

Question 11

explain the second wave of bacterial invasion of dentin :

Answer 11

mixed acidogenic and proteolytic organisms migrate extensively down the dentinal tubule , attacking the demineralized matrix

Question 12

how do microorganisms in dentin continue producing acids when they have been cut off from their primary source of nutrition ?

Answer 12

prolytic microorganisms break down protein content of dentin

Question 13

bacteria in adjacent tubules coalesce to form proteolytic areas called____

Answer 13

liquefaction foci (run parallel to the direction of the tubules

Question 14

lesions at right angle to the course of the dentinal tubules containing bacteria are called:

Answer 14

transverse clefts

Question 15

cavitation comenses from the___

Answer 15

DEJ

Question 16

whats the difference between acute and chronic dentinal caries in apperance?

Answer 16

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

Question 17

tubules of tertiary dentin are:

Answer 17

irregular , tortuous, and fewer in number than in primary dentin or may be absent

Question 18

root caries?:

Answer 18

-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

Question 19

early detection of caries (grading)

Answer 19

-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