class I and II resto Flashcards
most common cause of pulpal inflammation
microbial contamination
most common microbial source
caries
class I caries
lesions that occur in pits and fissures on the facial, lingual, and occlusal surface of M and PM, and lingual surface of max anterior teeth
class II lesion
lesions that occur in the proximal surfaces of posterior teeth
class V lesion
lesions that occur in smooth facial and lingual surfaces in the gingival third of teeth
how far deep should you go into dentin for cavity prep
0.5 mm
depth of amalgam in central area
2.0 mm
if the distance to the wall from the prep is >1.6 mm what should u do
convergent
if the distance to the wall from the prep is < or equal to 1.6 mm what should you do
divergent
what is extension for prevention
sacrificing sound enamel and dentin to place cavity margins into a “caries-immune” site
what does extension for prevention lead to
re-restoration cycle
why doesnt extension for prevention work
- resto is prone to failures
- does not guarantee caries-free
three preventative measures for controlling caries by preventive approach
- fluoride
- oral hygiene
- diet
HAP critical ph
5.5-6
FAP critical pH
4.5
two functions of fluoride
- form FAP crystals (acid resistant, decrease critical pH)
2. attract Ca+2 which attract PO4 ions (speed up remin)
which bacteria is abundant after cavitation
lactobacilli
what bacteria forms carious lesions
strep mutans
class V definition
lesions that occur on smooth facial and lingual surfaces in the gingival third of teeth
fissure caries disease process
- tip of triangle is towards surface
- follows enamel rods, hits dej, then goes down
smooth surface caries disease process
- base of triangle is towards surface
- follows enamel rods, hits dej, then goes down more
when do you do class v with amalgam
- moisture control is a problem
- high caries risk
- all sub gingival cases
occlusal boundary for class v cavity outline is
height of contour
stages of ecological hypothesis
- dynamic stability
- acidogenic
- aciduric
dynamic stability stage
- non-MS and actinomyces
- mild/infrequent acidification
acidogenic stage
- low pH non-MS and actinomyces
- moderate/frequent acidification
aciduric stage
- increase in MS and non-mutans aciduric bacteria
- sever/prolonged acidification
enamel and dentin have HAP-like minerals that are
more acid-soluble than pure HAP and FAP
HAP-like impurities in enamel and dentin contain
carbonate ions that replace the phosphate ions
-enamel (1 of 10), dentin (1 of 5)
what do carbonate ions in the crystal do
produce defects and calcium-deficient regions
-MORE susceptible to caries initiation :(
what happens during pH 4.5-5.5
- formation of FA
- FA precipitates on enamel
- brings Ca and PO4 ions to surface
3 roles of f-
- reduce enamel net demin
- speeds up remin
- forms FA crystal
5 zones of caries
- surface zone
- body
- dark zone
- translucent zone
- normal enamel
surface zone
highly mineralized
body of lesion
10-25% pores
dark zone
2-4% pores
translucent zone
1% pores
normal enamel
0.1% pores
where does caries begin on occlusal lesion
lateral fissure wall
grade 0
no change with prolonged drying
-sound tooth structure
grade 1
opacity visible after air drying
-demin in outer 50% enamel
grade 2
opacity without air drying
-demin between 50% enamel and outer dentin
grade 3
- enamel breakdown in opacity
- grey discolouration
- demin to middle third of dentin
grade 4
cavitation
-significant amount of dentin involved
critical pH pooint for cementum
6.2
why is it still easier to arrest progression of root caries than enamel caries
roots have greater reuptake of fluoride than enamel
