OPERATIVE Dental Caries Flashcards
which cells produce reparative dentin?
odontoblasts; they seal off dead tracts
___ is the process of occlusion of the dentinal tubules by peritubular dentin
sclerosis
dental caries is a multifactorial, transmissible infectious oral disease caused primarily by the complex interaction of ___ with ___on the tooth surface over time
cariogenic oral flora (biofilm) with fermentable dietary carbohydrates
T or F:
not all people with teeth and biofilm who consume carbohydrates have caries over time
true
at the tooth level, caries activity is characterized by ___
localized demineralization and loss of tooth structure
how does cariogenic bacteria cause dental caries?
- they metabolize refined CHOs and produce acid by-products, which can lower the pH if present for long enough
- low pH drives calcium and phosphate from the tooth to the biofilm, resulting in a net loss of minerals by the tooth (demineralization)
what is considered the critical pH level for enamel and dentin (below which demineralization occurs)?
enamel is 5.5, dentin is 6.5
what is the specific plaque hypothesis?
- not all of the 300 species of bacteria in the oral cavity can cause caries
- bacteria that generate plaque biofilm resulting in caries are considered to be cariogenic organisms
- all plaque biofilm is not cariogenic
is strep mutans gram positive or negative? motile or nonmotile? is it cariogenic?
cariogenic nonmotile gram positive
which bacterium is believed to be the primary causative agent of initial caries?
strep mutans
strep mutans adheres to ___. it’s ___ enzyme causes the formation of an extracellular polysaccharide, which allows it to stick to tooth surfaces. it converts sucrose to ___ and ___, which extrude from the bacterium and stick to the tooth. it produces and tolerates acid, and ultimately metabolizes sucrose to an end product of ___.
- enamel
- glucosyltransferase
- fructans and glucans
- lactic acid
strep mutans thrives in a ___-rich environment
sucrose
strep mutans ultimately converts sucrose for what two purposes?
tooth adherence and acid production
strep mutans produces ___, which kill off competing organisms
bacteriocins
in the formation of enamel caries, ion transfer continuously occurs at the ___ interface. initial decalcification occurs at the ___. how long might it take before enough decalcification occurs to cause surface integrity loss (cavity)?
- biofilm-enamel
- subsurface
- 1-2 years
in the formation of dentinal caries, once enamel cavitation has occurred, the underlying dentin has already been affected by the progression of the destruction. at this point, what organism becomes the primary agent for further destruction of the dentin?
lactobacillus
if sugars are the key to success of cariogenic bacteria (a major pathologic factor), then ___ is a major block barring those same bacteria (a major protective factor)
saliva
approximately how much saliva is formed each day?
1.5L
what are the protective mechanisms of saliva?
bacterial clearance, buffering action, antimicrobial actions, remineralization
how does saliva aid in bacterial clearance?
-glycoproteins (large CHO protein molecules) in saliva cause some bacteria to agglutinate and then be removed by swallowing the saliva
describe saliva’s buffering action
saliva contains urea and other buffers that help to dilute any plaque acids
what are the 4 proteins/enzymes/antibodies in saliva that discourage or even kill bacterial growth?
- lysozyme
- lactoferrin
- lactoperoxidase
- type A secretory immunoglobulins