Cariology Intro Hodgson Flashcards
3 main clinical reasons for losing teeth
non-restorable cavity, loss of periodontal support, trauma
teeth are ____ objects that exist in ______
mineral objects in solution
Teeth are made of minerals called ____
apatite
apatite is considered a ____
salt, exists in many forms
how teeth behave in solution?? Why?
Like salt in solution-thus they dissolve until the solution is saturated (reach equilibrium). This is because they are made of apatite which is considered a salt
Apatite in solution dissolves until what
the solution is saturated/equilibrium is reached
solution must be saturated with what to ensure teeth do not just dissolve away
calcium and phosphate ions
Apatite is lost via (4 ways)
corrosion (caries), attrition, abrasion, and abfraction
dental caries vs cavities
caries is the disease from acid produced by bacteria while cavities are the result of caries (the sign of disease i.e. a hole)
Factors for dental caries
tooth, acidogenic/aciduric bacteria, fermentable carbs/sugars
enamel structure is similar to __________? (which mineral)
mineral hydroxyapatite CaPOOH-may contain stray ions such as Na, Mg, Cl, Fl, and CO3
Structure of apatite crystals
long and thin, may run the full length of the enamel, also may fuse with adjacent crystals
In between apatite crystals
water and organic material (collagen matrix)
dimensions of an apatite crystal
100um long by 50nm thin
the solubility of individual enamel apatite crystals corresponds to the solubility of
enamel as a tissue
rate of dissolution in water and how it changes?
fast at first and then slows (stops when equilibrium is reached)
how we know when a soln is saturated with respect to the mineral
solubility product principle
solubility product principle
simply.. how we tell when a soln is saturated with respect to a mineral
this principle says that the V of a rxn (which is Ion Activity product or IAP) is proportional to the product of the masses of the reacting substances, each raised to the power equal to the number of molecules taking part
the effective concentration of an electrolyte or ion and is related to the chemical energy of salts or ions
activity?
Solubility product constant or KSP
identifies the equilibrium point of a mineral dissolution (point of saturation of the solution) at a specific pH and temp
KSP of HA is
7.41 X 10 ^-60 mol^9/I^9 at oH 6 and 37 C
Higher KSP means….
more soluble
When IAP = KSP
solution is at equilibrium
Ion Activity product or IAP
the Velocity of the rxn
IAP < KSP
solution is under saturated with respect to the mineral and dissolution of the mineral occurs (Demineralization)
IAP and KSP relationship in demineralization
IAP < KSP
IAP and KSP Relationship in remineralization
IAP > KSP
if IAP > KSP
Remineralization; the solution is super saturated with respect to the mineral and mineral formation occurs
How to determine IAP
simplify the chemical formula of hydroxy apatite and then multiply the compounds out
Critical pH
pH at which a supersaturated solution becomes just saturated with respect to the mineral (5.5 for HA), below this demineralization occurs
Why is enamel solubility affected by acid
The solubility of CaP is affected by pH of water…. more H+ ions react with PO4 and OH causing a shift in the equilibrium to favor dentin
Common Ion Effect and Examples
Excess of ion in soln requires less in soln to attain the KSP (equilibrium at certain pH) —Hence Ca and P in solution will reduce amount of HA dissolving as will doubling the OH (greater effect on IAP)
Things that reduce demineralization in acidic environments
Ca and P or Doubling OH has an even better effect on the IAP
Four Most common types of apatite crystals that compose enamel (in order from most to least soluble)
Carbonated HA (CAP)
Hydroxy AP
Flourapatite
Flourohydroxapatite
Highest concentration crystal type in newly erupted enamel
CAP
Solubilities of the apatite types
CAP > HAP > FAP > FHAP
Smaller or Larger KSP good? Thus CAP has a small or low KSP?
Small is good so CAP»_space;> FHAP
When net IAP ____ KSP remineralization happens and tooth becomes more acid resistant (matures)
IAP > KSP (remin)
If acid remains at or below critical pH HAP is more stable than CAP, HAP will….
be reformed over CAP and the outer enamel of the tooth will become more resistant to future mildly acidic challenges
when CAP or HAP dissolve in solution with Flouride in it
The solution is then supersaturated and results in the formation of FAP and FHAP
Morphology of newly precipitated crystals
small and contain many defects causing them to be more soluble
Overtime newly formed crystals tend to….. ?
reform and grow to reach their maximum size-this is referred to as Ostwalt ripening
Ostwalt ripening
Where newly formed crystals reform and grow to reach their maximum size
When amount of acid is not controlled and pH remains below 4.8
continous enamel dissolution will result with very little demineralization and nothing can be done for these patients
What keeps teeth from over remineralizing to the point of present crystals
crystal growth is very susceptible to poisoning by various substances
Crystal growth inhibitors on plaque free teeth include
salivary proteins such as tyrosine rich peptides, staherin, and various proline rich proteins coating the enamel surface which make up the pellicle
pellicle
proteins that coat the enamel surface
On plaque covered teeth what inhibits growth of crystals?
lowered pH, if pH raises above critical pH then calculus will form
When calculus forms
When Teeth are plaque covered and pH rises above critical pH
When is more flouride taken up? Think pedo
When the teeth have plaque, this is because of the equilibrium I guess
Critical pH of HA
5.5
