Midterm 1: Cariology II Approximal Caries Flashcards
Where are approximal caries?
between teeth
enamel - enamel contact
Class I caries are best prevented by what?
Fissure sealants
Posterior approximal caries begin ____________ to contact area.
gingival
Is there plaque retention between the posterior teeth?
YES
Demineralization can be inhibited by _________.
fluoride
How do posterior approximal caries form?
- undisturbed plaque on smooth surface
- plaque fed by carbohydrates
- mineral loss at center of lesion
What forms on the clean tooth surface to get caries?
pellicle
biofilm
There is a state of equilibrium between _______________ and the oral environment/plaque.
Hydroxyapatite
Ca10(PO4)6(OH)2 —> Ca2+ + PO43-
What is the critical pH for dentin?
6.2
What causes the pH to decrease?
sugar
increases [H+]
sugar increase H+ level which pulls the phosphate out of the tooth
What does bicarbonate do in saliva?
Bind with H+ to leave the equilibrium balance of calcium and phosphate untouched
Bicarbonate in saliva serves as a ________.
Buffer
distractor
What is saliva for and what does it provide for the mouth?
Natural rinsing (clearing bacteria/carbohydrates)
Bicarbonate (buffering capacity)
Calcium and phosphate
Fluoride
What is a Stephan Curve?
Shows the balance of remineralization/demineralization throughout time
What is the critical pH for enamel?
5.5
For a _____ mouth, it takes longer for pH to return to neutral
dry
What is the benefit of remineralization into fluorapatite?
fluroapatite has a critical pH of 4.5
better able to resist acid demineralization compared to hydroxyapatite
With fluoride, the critical pH is now 4.5, which means what?
It takes a stronger acid challenge to start demineralization
What are some characteristics of remineralization?
remineralization is a surface phernomenon
outer layer of enamel will remineralize
deeper enamel/affected dentin will not re-mineralize
will become shiner
radiolucency remains
Posterior approximal caries have little ________ evidence and no __________ evidence.
visual
tactile
How are posterior approximal caries diagnosed?
With X-rays
What are approximal caries (E2)?
acids begin to affect underlying dentin
loss of mineral subjacent to demineralized enamel
some discoloration from stains
NO spread of demineralization along DEJ
What are the categories of approximal caries?
E1
E2
D1
D2
D3
What are approximal caries (E1)?
Superficial deminirelization of enamel
No changes in dentin
What are approximal caries (D1)?
Cavitation of enamel
destruction of outer dentin
SUBSTANTIAL staining in dentin
enamel will begin to break down
spread in oval shape
stain all the way to the pulp even if the damage is to the dentin only
What are approximal caries (D2)?
Circumferential and axial destruction of dentin
possible pulp involvement
chalkiness
shadowing of occlusal
unsupported enamel broken away revealing dentin
demineralization extending into middle third of dentin
What are approximal caries (D3)?
Infection of pulp tissue
circumferential destruction of dentin and undermining of enamel is extensive
making repair with filling is UNRELIABLE
What is the progression of caries?
- enamel demineralization
- dentin demineralization
- enamel cavitation
- dentin cavitation
What are the pros and cons of panoramic radiographic diagnosis?
big picture
NOT SENSITIVE ENOUGH for approximal caries
if approximal caries are visible, TOO ADVANCED
What are the pros and cons of periapical radiographic diagnosis?
angle of x-ray beam is usually to low/high to highlight horizontal oval lesion
What should be used for radiographic diagnosis?
BITEWINGS
Why are bitewings used to diagnose approximal caries?
designed to show approximal lesions
show bone level
How to prevent approximal caries?
Reduce fermentable carbohydrates
Ex. sucrose, glucose, fructose, lactose
tooth brushing
flossing
fluoride
What is the worst fermentable carbohydrate?
sucrose
Why is sucrose so bad?
The oxygen that binds glucose and fructorse
Step mutans can use energy in that bond to link flucose with insoluble polymer: glucan
this linkage causes strep mutans to bind to tooth structure quickly and strong
What is surgical treatment for approximal caries?
remove defective tooth structure that is surrounded by solid tooth structure
access through marginal ridge
SIGNIFICAN weakening of tooth structure
Posterior approximal lesions require access through which sound tooth structure?
marginal ridge
__________ defects are easier to detect than _________ defects.
(enamel or dentin?)
enamel
dentin
Proper flossing and fluoride application are effective in preventing lesions unless they are __________.
cavitated
