Operative Flashcards
how long does it take for a proximal caries lesion to progress into dentin
average of 4 years
how long does it take for a pit and fissure caries lesion to progress into dentin
2-4 years
What is the main bacteria involved in caries
Strep Mutans
Besides Strep mutans what bacteria are involved in caries formation
S. Sobrinus
Lactobacilli
Bifidobacterium
actinomyces
What is the most important virulence factor in bacterial plaque
glucosyltransferases
what do glucosyltransferases do
synthesize water insoluble glucans from sucrose
what do the glucans synthesized by glucosyltransferases from sucrose do
they give plaque its sticky nature allowing it to adhere to the tooth
most commonly carious teeth
upper first molars
least commonly carious teeth
lower anterior teeth
how does saliva prevent caries
pH buffering
cleansing the tooth
supply of mineralizing ions
at what pH does decalicification occur
5.6
do infants without teeth have strep mutans
not until their teeth erupt
what does DMFT stand for
decayed missing or filled teeth
what are the benefits of fluoride
bacteriocidal
ions for remineralization of enamel
what percent of enamel is inorganic
96% (hydroxyapatite)
what percent of dentin is inorganic
70%
20% organic (mostly type 1 collagen and ground substance)
10% water
how to determine if white spot lesions are more or less than half way through the enamel clinically
if they are visible when the tooth is wet they are more than halfway through
if they are only visible when dry they aren’t more than halfway
clinical signs of arrested caries
white or brown
shiny surface
hard to explorer
clinical signs of active caries
chalky rough surface covered in plaque cavitated sticky with explorer
determining if radiographic interproximal lesions are active or arrested
active if.... high caries risk new lesion/progressing one from last X-rays caries into dentin inactive if.... no progression low caries risk
what is the mechanism by which caries detection dyes work
they are non-specific protein dyes that stain the organic matrix of less mineralized dentin (doesn’t differentiate between affected or infected dentin)
What are the 5 phases of a comprehensive treatment plan
systemic phase (general health problems) acute phase disease control phase definitive phase maintenance/monitoring phase
what is the critical pH of fluorapatite
4.5 (hydroxyapatite is 5.5)
what is CPP-ACP and what is it used for
casein phosphopeptides and amorphoyus calcium phosphate
used for remineralization
what is the typical concentration of NaF varnishes
5% (every few weeks)
what is the typical concentration of NaF fluoride gels trays
5000 ppm (1-2 x per day, 5 minutes, 2-4 months)
what surfaces is F most effecticve
smooth surfacs
what is the maximum F dose per day for adults
5mg/kg/day
at what dose of F does fluorosis become possible
.7mg/kg/day
Advantages of GI
- forms a chemical bond with dentin and enamel
- no bonding agent needed
- fluoride release (rechargable)
- strongly resistant to secondary decay
- adding resing increases strength
- acceptable but not great aesthetics
- less problems with water contamination
- conservative preps
Disadvantages of GI
- low fracture resistance
- not for marginal ridges, incisal edges, cusp tips etc
- poor color match
- poor polishability
- dehydrate and disintegrate in low salivary flow
- need to be sealed to prevent microleakage
Advantages of Composite
- excellent aesthetics
- can withstand moderate occlusal loads
- micromechanical bonding with enamel and dentin
- conservation of tooth structure
Disadvantages of composite
- expensive
- bonding and curing required
- potential allergens
- high wear in posterior (compared to amalgam, better than GI)
- prone to leakage over time
Advantages of RMGI
- some fluoride
2. better strength and wear than GI
disadvantages of RMGI
- require bonding and curing
2. less strength and wear resistant
Advantages of Amalgam
- inexpensive
- self curing
- durable
- great for high stress
5, easy placement - corrosion helps seal margins from recurrent decay
disadvantages of amalgam
- poor aesthetics
- more aggressive tooth prep
- environmental concerns
- allergy potential
preventing marginal breakdown
- keep margins away from direct occlusal loads
- choose right material
- don’t bevel occlusal resin margins
- 90% cavosurface margins
what are the common causes of GI failures
- poor placement technique
2. inadequate bulk
what are the common causes of resin failures
- poor placement technique
- poor moisture control
- inadequate cure
- excessive shrinkage
causes of amalgam fractures
- inadequate retention or resistance form
- inadequate thickness
- inadequate condensation
- degradable (ZOE) liner
what is the average thickness of dentin
3 mm
what is added to composites to make them self curing
benzoyl peroxide
what is the wavelength at which composites cure
468 nm
what is pilocarpine used for (Rx)
xerostomia
