Materials Flashcards
List the rank order of quality studies. best to worse
Systematic Reviews and Meta analysis
Randomized controlled double blind
cohort
case control
case series
case reports
ideas, editorials, opinions
animal research
in vitro research
Amalgam is better in posterior teeth is supported by what
Cochrane Summaries (OCT 2013)
Moraschini- J Dent 2015- 46% high probability of failure in composites.
Vetromill, JADA 2020- 5yr f/u
what convention lead the the international decision to decrease mercury waste?
Minamata Convention
Chairside traps, vacuum pump and filters remove how much of amalgam?
80%
What % of mercury entering public water treatment facilities is from dental? but how much of it is released into the enviroment?
50%, <1%
What is a requirement if you use or take out amalgam?
amalgam separator
(required as of JUL 2020) Office cost ~800/annually
How does an amalgam separator remove amalgam
sedimentation, filtration, and ion exchange
FDA recommends not to use amalgam in what individuals
- pregnant
- breast feeding
- <6yo
- Mercury of (silver, copper, tin zinc sensitivities)
- kidney or neurological dysfunction
all with poor evidence
What is the gold standard in adhesive bonding agents?
3 step Etch and Rinse: (Etch, rinse, conditioner, primer, adhesive) 1. Optibond FL, 2. clearfil SE (selective etch)
For NCCLs what bonding performs the best? and 2nd best?
- two step, self etch (Clearfil SE)
- 3 step, etch and rinse, (optibond FL)
then GI>RMGI,>two step etch and rinse>polyacid modified composite resins >one step self etch
(Heintze, Dent Mater 2010, and Mahn J adhesive Den 2015)
What is the monomer developed in 1981 by Kuraray that is new to universal adhesives?
10-MDP monomer
(10-Methacryloyloxydecyl dihydrogen phosphate)
high bond when
compared to Bis-GMA resin composite
Best universal adhesive
Scotchbond universal- 93% retention for e&R, 88.4% w/ selective E, and 81.4- self stch.
Scotchbond universal- does it bond will to ceramics? Zirconia?
Ceramics/Emax: no, not without additional silane use.( has silane in it)
Zirconia- effective bond strength.
silane ineffective in bond bc of its low pH, weaken by dehydration self condensation.
What are MMPs an what inhibits them? Does it matter?
Matrix metalloproteinases (MMPs 2, 8, 9)
-Cysteine cathepsins
–- endogenous enzymes
–- collagenolytic
INHIBITS: CHX
Matter: no. CHX does not influence clinical outcomes
Gluma is?
5% glutaraldehyde and 35%
hydroxyethylmethacrylate (HEMA)
Gluma is good at?
Not supported be evidence?
cervical dental hypersensitivity
Not supported to be used under restorations- no decrease in sensitivity
Desensitizers and bond strength: what had no negative effects
CPP-ACP (like MI paste)
and arginine-CaCO3
Bond strength: CHX?
MAYBE preserve bond strength
Bond strength: EDTA and ethanol
positive results, but not enough research to recommend
Bond strength: laser, fluoridated agents, NaOCl
no idea. not enough evidence- so avoid it!
Bond strength: SDF?
4 studies said no difference, 4 studies said reduced,
no difference with GI bonding
Bond strength: Air Abrasion
afraid with aluminum oxide
-no negative effects on bond strength
* resin-based materials to dentin
– improved immediate bond strength
* particle size >30 um
* air pressure > 5 bar
– however, no improvement over the long term
Immediate Dentin Sealing (IDS)- does it work?
lab studies show improved bond strength, fewer gap formations, and decreased bacterial leakage.
only limited randomized clinical studies
DOES NOT reduce post op sensitivity with indirect restorations
IDS- 3 yr clinical study (Van den Breemer J Dent 2019) showed…
emax press, vital teeth
no significant difference in sensitivity or anything else.
11 yr IDS (gresnigt Dent Mater 2019)
feldspathic veneers.
more than 50% dentin exposure had significant increase in survival with IDS (96.4% vs 81.8%)
Composites are classified by what?
monomer type and particle type
Composite monomer types?
Methacrylate: Bis-GMA, UDMA, TEGMA
Composite particle types
macrofill, microfill, hybrid, nano
Particle size in macrofil
10-50 um
Particle size in microfill
40-50 um
Particle size in hybrid
10-50um + 40nm
Particle size in nanofill
5-100nm
Particle size in minifill
0.6-1um +40nm
Particle size in midifill
1-10um +40nm
nanohybrid is made of:
nanofill and minifill
microhybrid is made of
??
which size is better for posterior restorations?
nano vs nanohybrid vs hybrid
what does yttrium do to zirconium crystals?
stabilizes poly crystals
Waht does the aluminum do to zirconium
prevents water corrosion
What are phases of zirconia and which is the strongest
Cubic-most translucent
Tetragonal - STroNGEST
monoclinic- largest
What is the difference between 3, 4, and 5mol % yttria?
3 mole: STRONGEST because it has 85% in tetragonal phase
4 mol: 75% tetragonal, 25% cubic
5 mol: 50% tetragonal, 50% cubic = more translucent/esthetic but weaker
What is transformation toughening?
Zirconia tetragonal particles transform to monoclinic (bigger) particles to prevent crack propagation. seen more in 3Y because of the higher tetragonal configuration.
What is GLUMA and with is its composition?
Desensitizer=
5% Gluteraldehyde, 35% HEMA (hydroxyethylmethacrylate)
What is SDF, %, ppm, and what it is for?
38% Silver diamine fluoride
44,800 ppm
FDA = for hypersensitivity
Off label- caries arresting
side effects of SDF?
dark color change
What does a higher filler particle do for composite?
improve mechanical properties
decrease polymerization shrinkage
decrease thermal expansion
What are the phases of amalgam?
Gamma: Silver Tin, 30% of volume, strongest phase
Gamma 1: silver mercury, 60% of volume, major matrix phase in set amalgam
Gamma 2: Tim Mercury: 10% of volume, weakest and softest phase that corrodes easily
Eutectic: copper tin.
copper prevents gamma2
What does higher concentration of copper do for amalgam?
eliminates the Gamma 2 phase which is the weakest.
increases corrosion resistance
greater strength
less tarnish
greater longevity
Describe the phase reaction of high copper amalgam alloys
Silver enters mercury from silver-copper spherical eutectic particles
both silver and tin enter mercury from stagnant silver particles
tin diffuses to the surface of silver-copper particles
it reacts with copper to form a copper/tin around the unconsumed silver-copper particles
Gamma 1: particles surround the copper compound with tin (ETA phase) and alloy particles
Gamma 2: alloy particles are replaced by copper tin particles
What is the argument against amalgam?
-Public perception (mercury)
-Esthetics
-Environment
-Safety
How is amalgam discharged into the environment?
-Wastewater discharge
-Chairside traps, vacuum pump filters to remove up to 80% of amalgam particles discharged into sewers
-Main source of publicly owned tx works
-its less than 1% of mercury released into the environment from man-made sources
2020 EPA ruling makes it mandatory
What are amalgam rules in the EU?
No amalgam on deciduous teeth,
kids under 15,
pregnant or breastfeeding women
EU parliament exploring ending amalgam use by 2030
What is the FDA’s stance on amalgam?
2019: insufficient evidence of a relationship between clinically detectable adverse health outcomes and dental amalgam mercury exposure
no Amalg for preg/breastfeeding, children under 6, CKD, or brain issues due to mercury localizing there
What are the most common used crown materials?
Zirconia- 58%
Glass ceramics: 18%
PFM: 17%
Gold 5%
Resin ceramics: 0.9%
Which two methods have the best performance and lowest failure rates in treating NCCLs?
2 step SELF E and R (Clearfil SE): best performance
3 Step E and R (Optibond FL): lowest annual failure rate
What is IDS and is it effective?
Immediate dentin sealing- seal dentin tubules immediately after prep
somewhat equivocal regarding benefit. if >50% exposed dentin, significant increase in survival rate with IDS.
