Indirect Exam 2 Flashcards
What are the 4 types of all ceramic crowns?
Feldspathic porcelain
Lithium disilicate
PFZ
Monolithic zirconia
What type of prep design?
Feldspathic porcelain
Lithium disilicate
ACC prep
What type of prep design?
PFM
PFZ
PFM prep
What type of prep design?
FMC
Monolithic zirconia
FMC prep
When are ACCs indicated?
Esthetics
Enough coronal dental structure to support restoration
When doing an ACC, ___________ on occluding surface should be supported by the abutment tooth
porcelain
Porcelain is relatively __________
weak/brittle
What type of crown should you do?
Tooth that has an extensive proximal and/or buccal restoration that can no longer be restored with composite
ACC
What type of crown should you do?
A more conservative restoration is inadequate
ACC
When are ACCs contraindicated? (7)
When a more conservative restoration is indicated
Posterior teeth
Discolored teeth
1mm margin is not possible
Occlusal load is unfavorable (edge-to-edge occlusion)
Parafunctional habits
Deep overbite
Why should you not put an ACC on posterior teeth?
High occlusal load/brittle porcelain
Ceramic can’t exceed more than 2mm in thickness
Why should you not put an ACC on discolored/stained teeth?
May alter final restoration shade
What are the 3 advantages of ACCs?
Superior esthetics (high translucency)
More conservative on facial surface (1mm) compared to PFM (1.5mm)
Shade can be modified by resin cement
What are the 2 multi-shaded resin cement systems?
Variolink esthetic
RelyX veneer
What are the 2 disadvantages of ACCs?
Not strong
Less conservative margin compared to PFM
Why are ACCs not as strong?
No metal/zirconia substructure
What is the MPa of feldspathic porcelain vs lithium disilicate?
Feldspathic porcelain: 100-150
Lithium disilicate: 360-400
What is the margin of ACC vs PFM crowns?
ACC: 1mm, 90 degree shoulder, deep chamfer
PFM: 0.5mm, feather edge, light chamfer
How many facial planes are there on anterior ACC preps?
2
What is the incisal edge reduction on anterior ACC preps?
1.5-2mm
What is the axial wall reduction on anterior ACC preps?
1-1.5mm
Why do you want a 90 degree shoulder or deep chamfer for ACC preps?
Prevents unfavorable distribution of stress
Minimize risk of fracture
Ideally, you want _______ contacts in the middle 1/3 of the __________ surface for an ACC prep
MIP; lingual
When prepping for an ACC, ____________ guidance should be smooth and consistent
anterior
T/F: For an ACC prep, leaving the tooth out of
occlusion should be avoided, since it will erupt and may lead to protrusive interferences/possible fracture
True
What is the axial wall reduction on posterior ACC preps?
1.5mm
What is the non-functional cusp reduction on posterior ACC preps?
1.5mm
What is the functional cusp reduction on posterior ACC preps?
2mm
Before starting an ACC prep, what should you do if you are not satisfied with the existing crown’s anatomy?
Make a wax-up to the ideal contours you’re restoring to
What is the benefit of making a wax-up to the ideal contours you’re restoring to prior to starting an ACC prep?
The reduction guide will truly guide you, since that’s the anatomy you’re looking for in the future crown
When reducing on the facial surface during an ACC prep, what should the cervical reduction follow?
The path of insertion
When reducing on the facial surface during an ACC prep, what should the incisal reduction follow?
The anatomical curvature it follows
What should you do when prepping to prevent stress concentrations in an ACC?
Round internal line angles
Which bur should you use when finishing the margin of an ACC prep to get a very smooth, continuous shoulder margin?
Red labeled diamond
Properties and behavior of materials depend on __________ structure
internal
Independent of mechanical manipulation
Physical properties
Associated with response to externally applied forces
Mechanical properties
Name 7 physical properties
Density
Coefficient of thermal expansion
Optical
Solubility
Viscosity
Electrical/thermal conductivity
Melting/solidification point
What is testing of mechanical properties a useful predictor of?
Clinical success - can compare to other materials
Push or pull exerted on a material
Force (load)
Has magnitude and direction
Force (load)
Units are pound and Newton (0.22lb)
Force (load)
Force per unit area
Stress
What are the 3 types of stress?
Tension (<- ->)
Compression (-><-)
Shear
What type of stress?
2 forces directed away from each other in same straight line
Tension
What type of stress?
2 forces directed toward each other in same straight line
Compression
What type of stress?
2 forces directed toward each other, but NOT in same line
Shear
What happens when force exceeds the cohesive strength of the object?
It breaks
What does stress depend on?
Area and load
What are the biting forces of molars, premolars, and incisors?
Molars: 130 lbs
Premolars: 70 lbs
Incisors: 40 lbs
What is the biting stress of molars?
130,000 psi
What is amalgam’s ratio of tensile strength to compressive strength?
Tensile strength is 1/10 of compressive strength
What is EvoCeram’s ratio of tensile strength to compressive strength?
Tensile strength is 1/5 of compressive strength
Small flaws caused by localized high stresses like a notch or scratch
Stress concentration
Results in unexpected fracture at low stress
Stress concentration
Change in length/original length
Strain
Amount of deformation per unit length
Strain
An object is deformed when a force is applied
Strain
Measure of the level of stress required to make a material fail
Strength
What is the importance of strength?
Restorations must withstand stresses of mastication
What is important in dentistry to avoid exceeding strength properties of a material?
Prep design
Graphic representation of the deformation of a material as stress is applied
Stress-strain diagrams
Initially, strain is proportional to stress and is reversible
Elastic deformation
Ratio of stress to strain in straight line
portion of a diagram
Modulus of elasticity
This property cannot be changed, as it is a measure of interatomic bonding
Modulus of elasticity
Relates directly to rigidity of material
Modulus of elasticity
The greater the modulus of elasticity, the more __________ a material will be
rigid
The steeper the slope, the more ________ the material
rigid
At higher stresses, permanent displacement of atoms occurs so that much of the strain is not reversible
Plastic deformation
Once it starts, the strain will increase faster than the stress
Plastic deformation
Max stress a material can withstand without deviation from the law of proportionality
Proportional limit
An increase in the proportional limit will ____________the resistance of the material to permanent deformation
increase
High proportional limit is…
Strong
Low proportional limit is…
Weak
Essentially same as proportional limit
Elastic limit
Stress at which a material exhibits a small amount of permanent deformation
Yield strength (point)
Amount is arbitrarily selected
Yield strength (point)
Any restoration or appliance that permanently deforms in service is usually what?
A clinical failure
A material with a yield strength greater than
30,000 psi can’t be ___________
burnished
Max stress before failure
Ultimate strength
Deformation from applying a tensile force
Elongation (ductility)
Indication of workability (burnishability) of an alloy
Elongation (ductility)
Increase in length/original length x 100 = ?
% elongation
Total % elongation includes what types of deformation?
Elastic + plastic
An alloy with a high value of total % elongation can be bent permanently with less risk of _____________
fracture
In regards to total % elongation, what value is needed to be useful?
10%
Ability to be hammered or rolled into thin sheets
Malleability
Ability to be drawn into wire
Ductility
Related to burnishability
Ductility
Wrought wires are ___________
flexible
Cast alloys are ____________
ductile
Measured by area under the elastic portion of a stress-strain diagram
Resilience
Amount of energy needed to deform a material to its proportional limit
Resilience
Capacity to withstand repeated stresses before deforming
Resilience
Area under the total curve of a stress-stain diagram
Toughness
Amount of energy necessary to fracture a material
Toughness
Capacity to withstand repeated stresses before fracturing
Toughness
Resistance to permanent indentation
Hardness
Size of the indentation varies inversely
with the ____________ of the material
Hardness
The higher the hardness number, the _________ the material
harder
What are the 4 testing methods for hardness?
Brinell hardness
Diamond pyramid
Knoop hardness
Rockwell hardness
Which testing method for hardness?
Small steel ball: ratio of load to area of indentation
Brinell hardness
Which testing method for hardness?
Uses a diamond pyramid instrument
Diamond pyramid
Which testing method for hardness?
For metals and alloys, not brittle materials
Brinell hardness
Diamond pyramid
Which testing method for hardness?
Diamond tool with one long diagonal and one short diagonal
Knoop hardness
Which testing method for hardness?
Cuts the material
Knoop hardness
Which testing method for hardness?
For brittle materials (enamel, dentin), elastics, and metals
Knoop hardness
Which testing method for hardness?
Depth of indentation measured directly on
a micrometer
Rockwell hardness
Which testing method for hardness?
For elastic materials
Rockwell hardness
What is the clinical significance of yield strength?
Burnishability
What is the clinical significance of tensile strength?
Load-bearing ability
What is the clinical significance of elongation?
Margin-finishing properties
What is the clinical significance of hardness?
Wear resistance
Finishing/polishing
What is the dental wax called?
Inlay or casting wax
Amorphous, organic material
Wax
Wax is solid at what temp?
Room temp
Wax melts without _____________
decomposition
What are the natural sources of wax?
Mineral petroleum distillation
Plants
Insect
What are the 3 things involved in mineral petroleum distillation that make up inlay wax?
Paraffin
Microcrystalline
Ceresin
Which plants make wax?
Canauba
Candelilla
Which insects make wax?
Bees
T/F: The composition of beeswax varies
True
Which waxes are used more often in dentistry, natural or synthetic?
Natural
Describe synthetic wax
Highly refined
Similar properties to natural wax, but differ chemically
What are the 4 additives in wax to make it more stable/easier to carve?
Stearic acid
Oils
Resins
Rosins
What do the additives in wax allow adjustments for?
Flow
Toughness
What is the composition of wax?
Hydrocarbons
Esters
Complex combo of organic compounds
Does wax have a high or low molecular weight?
High
What is the primary ingredient in casting wax?
Paraffin (60%)
T/F: Wax has a melting point
FALSE, wax has a melting RANGE (since it has various molecules with differing molecular weights)
The melting temp of wax increases when…
Molecular weight increases
T/F: Wax has the largest thermal expansion coefficient of any material in restorative dentistry
True
The thermal expansion of wax is a function of strength of ___________ valence forces
secondary
Which forces hold materials in wax together?
Secondary
Do mineral waxes have strong or weak forces?
Weak
Which one has a greater force: mineral wax or plant wax?
Plant wax
What are the 2 contractions in wax?
Solidification shrinkage
Cooling contraction
What is a major factor in the inaccuracy of a finished restortation?
Temp changes in wax pattern
Does wax have a high or low elastic modulus (rigidity)?
Low
What does elastic modulus (rigidity) of wax depend on?
Temperature
Does wax have a high or low strength?
Low
Ability to flow over a surface
Wetting
Do you want the contact angle of a wetting surface to be high or low?
Low
Ideal/perfect wetting has what degree of a contact angle?
0 degrees
What aids wetting?
Die lubricant
Die lubricant is basically the same as what material?
Liquid alginate
Degree of plastic (permanent) deformation of a material at a given temp
Flow
What 3 things does flow depend on?
Temp
Force applied
Time force is applied
What is always present in the wax pattern?
Residual stress
What does molding wax under compression lead to?
Expansion
What does molding wax under tension lead to?
Contraction
What are the 2 types of casting waxes?
Type 1 (technicians use)
Type 2
Which type of casting wax?
Harder
Lower flow for direct technique in oral cavity
Type 1
Which type of casting wax?
Soft for indirect technique on stone model
Type 2
T/F: Both type of casting wax should trim to a fine margin
True
What is a problem with both types of casting wax?
Warping
What are the 4 problem areas of wax?
Development + release of internal stress
Non-uniform storage temps
Carving that induces stress
Warming the pattern
A wax pattern is made directly on the __________
stone model
What is painted on the die? Why?
Die lubricant; allows wax to flow easier
What 5 things should you check the wax pattern for?
Overwaxed margins
Short margins
Thick margins
Open margins
Roughness
What are the 2 major categories of impression material?
Inelastic (rigid)
Elastic (flexible)
Which category of impression material?
Plaster, ZOE, compound
Inelastic (rigid)
Which category of impression material?
For edentulous pts
Inelastic (rigid)
Which category of impression material?
Hydrocolloids (reversible and irreversible)
Elastic (flexible)
Which category of impression material?
Elastomers (polysulfide, condensation silicone, addition silicone, polyether)
Elastic (flexible)
What was the first impression material to come out in 1950?
Polysulfide
Which impression materials do not have a byproduct, meaning they are stable and can be sent later to a lab without warping?
Polyether
Additional silicone
T/F: If the impression material doesn’t have a lot of filler in it, you will have a more detailed impression
True
T/F: Fillers in impression material will stabilize the dimensions of it
True
What are the 2 lead-free polysulfides?
Omniflex
Coe flex
Which impression material has the following ingredient?
Catalyst- cupric hydroxide
Omniflex
Coe flex
(lead-free polysulfides)
What are the available consistencies of polysulfide and polyether?
Light
Regular
Heavy
Do you dispense in equal lengths or equal volumes of impression material?
Equal lengths
Which impression material has the following properties?
Unpleasant odor
Stains clothes
Extremely viscous + sticky
Hydrophobic
Polysulfide
Which impression material has the following chemistry?
Condensation rxn (water is produced)
Chain lengthing rxn (viscosity increases)
Cross-linking rxn
Polysulfide
Which impression material has terminal and pendant mercaptan groups (-SH)?
Polysulfide
What are the terminal and pendant mercaptan groups in polysulfide oxidized by? What does this produce? What is there a rapid increase in?
Lead dioxide to produce chain lengthening and cross-linking; increase in molecular weight
What are the available consistencies of condensation silicones, addition silicones, and VPES?
Light
Regular
Heavy
Putty
Which impression material has the following properties?
Almost odorless
Variety of colors
Hydrophobic
Condensation silicones
Which impression material has the following chemistry?
Condensation rxn (alcohol is produced)
Chain lengthing rxn (viscosity increases)
Cross-linking rxn
Condensation silicones
What are the 2 other names for addition silicones to know for boards?
Polyvinyl siloxane
Vinyl polysiloxane
Hydrophilic formulations of addition silicones contain what?
Surfactant
Which contains the most amount of filler - putty or light body?
Most amount of filler = putty
Least amount of filler = light body
Which impression material?
Consistency depends on molecular weight of polymer and amount of filler
Addition silicones
Which impression material?
Supplied as 2 pastes, or putty, or in dual cartridge system
Addition silicones
Which impression material?
Can do a heavy-wash 1-stage impression (like how we do for crown preps)
(wash = light body)
Addition silicones
Which impression material?
Can do a putty-wash 2-stage impression
(wash = light body)
Addition silicones
Which impression material has the following properties?
Almost odorless
Variety of colors
May cause bubbles in stone
Naturally hydrophobic
Addition silicones
Which impression material has the following chemistry?
Addition rxn (no volatile byproduct; some forms produce hydrogen)
Chain lengthing rxn (viscosity increases)
Cross-linking rxn (elasticity increases)
Addition silicones
What groups contribute to chain lengthening and cross-linking in addition silicones?
Vinyl groups
Which impression material?
Sets by uniting polymer chains (polymerization)
Addition silicones
Name the impression materials with the fastest working times in order
Addition silicones
VPES
Alginate
Which impression material?
The catalyst (benzene) used to cause a soft tissue rxn after the 2nd or 3rd impression with this material (catalyst has been changed now)
Polyether
Which impression material has the following properties?
Almost odorless
Possible skin rxns (not anymore due to change in catalyst)
Naturally hydrophilic
Polyether
Which impression material has the following chemistry?
Addition rxn (no byproduct)
Polyether
Which impression material?
Cationic polymerization and opening of the rings
Polyether
What is vinyl polyether silicone (VPES) a combination of?
Addition silicone + polyether
Which impression material has the following properties?
Intrinsically hydrophilic
Good flow
Low contact angle (10 degrees)
Easier removal than polyether (increased flexibility)
High tear strength
Vinyl polyether silicone (VPES)
Which impression materials are easier to mix due to lower initial viscosity?
Silicones
Which impression materials have the most rapid increase in viscosity?
Addition silicone
Polyether
There is a decrease in viscosity with increasing ___________
shear rate
What are 3 words used to describe the act of putting pressure/force behind impression material to thin it out?
Shear thinning
Pseudoplastic
Thixotropic
Which impression material has the longest working time and setting time?
Polysulfide
(next longest are silicones and polyethers)
What are working times and setting times shortened by?
High temp
Humidity
What does shrinkage of impression material occur from?
Evaporation of volatile byproduct
Thermal contraction
Rearrangement of bonds during polymerization
Which impression material has the smallest and largest dimensional change/shrinkage?
Smallest = Addition silicone
Largest = Condensation silicone
Which impression materials absorb water?
Polyether
Hydrophilic addition silicone
(do NOT wrap these up in a paper towel)
Which impression material has the best recovery?
Addition silicone
Which impression material has the worst recovery?
Polysulfide
Which impression material is the stiffest?
Polyether
Which impression material is the least stiff?
Polysulfide
Which impression materials have the lowest and highest amount of flow?
Lowest = Silicones + Polyether
Highest = Polysulfide
Which impression material is the hardest and least hard?
Hardest = Polyether
Least hard = Polysulfide
Which impression material is the easiest to remove from a pts mouth, due to the fact it is the least stiff and least hard material?
Polysulfide
Which impression material has the highest and lowest resistance to tearing?
Highest = Polysulfide
Lowest = Polyether
Which impression material is most likely to tear when removing it from the pts mouth?
Polyether
Alginate impression material is a ____________
hydrocolloid
“Hydro” in hydrocolloid means __________ is the dispersion medium
water
“Colloid” in hydrocolloid means solution in which the dispersed particles are __________ than ordinary atoms or molecules, but still invisible to naked eye
larger
What are the 2 forms of hydrocolloids?
Sol
Gel
Which form of hydrocolloid?
Aggregates of molecules are dispersed within water and material behaves like a high viscosity fluid
Sol
Which form of hydrocolloid?
Semisolid mass formed by reduction in temp or chemical rxn
Gel
Which form of hydrocolloid?
Molecules join to form a network of chains (fibrils) which enclose the dispersion medium (water)
Sol
Gel
How do hydrocolloids behave?
Drying
Imbibition
Syneresis
Which behavior of hydrocolloids?
Evaporation of water from gel under conditions of high ambient temp and low humidity
Drying
Which behavior of hydrocolloids?
Shrinkage
Drying
Which behavior of hydrocolloids?
Water absorbed with associated swelling of the gel
Imbibition
Which behavior of hydrocolloids?
Will NOT restore the original dimensions to the gel
Imbibition
How fast should hydrocolloid impressions be poured up?
Within 2 hrs
Which behavior of hydrocolloids?
Appearance of exudate on surface of impression (sticky layer)
Syneresis
Which behavior of hydrocolloids?
Occurs independent of humidity; doesn’t matter if you wrap it up in paper towel
Syneresis
What type of rxn is in Alginate?
Irreversible rxn
How does alginate set?
Chemical rxn
Which impression material?
Uses:
Preliminary impressions for CDs and RPDs
Study model impressions
Alginate
Alginate is _______ to mix
easy
What should you do with the extra Alginate in the bowl? What does this help with?
Put it on your finger and apply to posterior teeth; helps get rid of air bubbles
Which 2 ingredients bond to each other in Alginate impressions?
Sodium alginate + calcium sulfate
Which ingredient in Alginate helps improve the surface of stone by counteracting gypsum inhibition?
Potassium sulfate
Which ingredient in Alginate is a retarder?
Sodium phosphate
Which ingredient in Alginate controls consistency?
Fillers
What are the setting rxns of Alginate?
Retarding (ties up the Ca2+ ions)
Setting (Na alginate reacts with Ca2+ sulfate and water; product is Ca2+ alginate)
_________ ___________ is essentially insoluble in water; it’s formation causes gelation
Calcium alginate
(it is the product of Alginate setting rxn)
The concentration of what ingredient in Alginate is adjusted to provide regular and fast set impression materials?
Sodium phosphate
Which impression material?
Proportioning the powder/water ratio is critical for consistent results
Alginate
Which impression material?
Fluff the powder before scooping, but don’t inhale it
Alginate
Which impression material?
Mixing time:
1 min for regular set
45 seconds for fast set
Alginate
Which impression material?
Rinse impression with (slurry) water to remove saliva and then disinfect
Alginate
Which impression material?
Setting time:
No less than 2 mins, no more than 4.5 mins for regular set
No less than 1 min, no more than 2 mins for fast set
Alginate
Which impression material?
Adjust setting time by altering water temp
Alginate
How do you make Alginate set faster?
Use warmer water
How do you know if Alginate is set?
Loses surface tackiness
Which impression material?
Wait 2-3 mins before removing from pts mouth to increase tear strength and resistance to permanent deformation
Alginate
Permanent deformation of Alginate is a function of…
% compression of material
Time under compression
Time after removal
What is meant by % compression of material?
A bulk of material will absorb compression
What will increase deformation of an Alginate impression?
Slow removal from pts mouth
How long should you let the Alginate impression recover after removing from pts mouth?
8 mins
Which impression material?
One of the most flexible impression materials
Alginate
Which impression material?
Tear strength increases with increased rate of removal from pts mouth
Alginate
What is dimensional stability of Alginate due to?
Loss or gain of water
Loss of water in an Alginate impression due to evaporation or syneresis leads to what?
Shrinkage
Gain of water in an Alginate impression due to imbibition leads to what?
Expansion
Store your Alginate impression in _____________ (wet paper towel) for up to 2 hrs
100% humidity
Pure calcium alginate is ___________
brittle
The double alginate structure is ____________ to a sudden force, but not to a prolonged force
elastic
What kind of rxns does Agar hydrocolloid use?
Reversible rxn
Conversion rxn
Which impression material?
Gel upon cooling, liquifies when heated
Agar hydrocolloid
Which impression material?
Heating units and special trays are required
Agar hydrocolloid
Which impression material?
Dimensionally unstable; difficult to register subgingival areas
Agar hydrocolloid
Which impression material?
Thermal shock
Agar hydrocolloid
Which ingredient in Agar hydrocolloid functions as the fibril structure of gel?
Agar
Which ingredient in Agar hydrocolloid improves surface of stone?
Potassium sulfate
Which ingredient in Agar hydrocolloid improves strength of gel?
Borax
Which ingredient in Agar hydrocolloid is a preservative?
Alkyl benzoate
Which ingredient in Agar hydrocolloid is the continuous phase?
Water
Difference btwn gel -> sol and sol -> gel transformation temps in Agar hydrocolloid
Hysteresis
Describe the conversion rxn in Agar hydrocolloid
Gel -> heat to 212 -> sol (liquid)
Sol (liquid) -> cool to 109 -> gel
Which impression material?
Store at 145-150 degrees
Temper at 115 degrees for 2 mins
Agar hydrocolloid
Which impression material?
Properties are similar to Alginate
Agar hydrocolloid
Which category of cement?
Stronger, more stable, bond to tooth structure
Polymer based
Which category of cement?
Oil based, water based, do NOT bond to tooth structure
Traditional
Name 2 traditional cements
Zinc oxide - eugenol (ZOE)
Zinc phosphate
What are ZOE, silicophosphate, and GI used for?
Temp filling material
What are silica and GI used for?
Durable filling material
What are ZOE, zinc phosphate, polycarboxylate, and GI used for?
Cavity liner/base
Which cement is the only one that is NOT used for cementation?
Silicate cement
Which cement is insoluble in the pts mouth and highly acidic?
Zinc phosphate
Which cement is very soluble in the pts mouth and will sedate the pulp?
ZOE
What characteristics are in an ideal final cement?
Adequate working time
Short setting time
Resistance to dislodging forces
Adequate flow
Adhesive
Resists plastic deformation (high elastic modulus)
Anticariogenic
Translucent
Thin film thickness
Non-toxic
Easy to clean up
Low solubility
High compressive strength
Which traditional cement?
Strong and rigid; irritant because it is acidic
Zinc phosphate
Which traditional cement?
No adhesion, no anti-bacterial properties
Zinc phospahte
What is the main powder ingredient in Zinc phosphate and ZOE cements?
ZnO
What is the main liquid ingredient in Zinc phosphate cement?
Phosphoric acid (H3PO4)
(this is where the acidity comes from)
Which traditional cement?
Components are fused by heating (calcination) and then ground to fine powder
Zinc phosphate
Which traditional cement?
Metallic oxides added for color
Zinc phosphate
Which traditional cement?
Made up of 30% water, which controls ionization of the acid
Zinc phosphate
What shortens the setting time of Zinc phosphate?
More water
Which traditional cement?
Surface of powder is dissolved by the acid, which is an exothermic rxn
Zinc phosphate
Which traditional cement?
When it sets, you will have an amorphous network surrounding incompletely dissolved ZnO
Zinc phosphate
The smaller the particle size in a material, the ____________ (faster/slower) the material will set
faster
What 5 factors does the operator control when using Zinc phosphate cement?
Powder/liquid ratio
Rate of powder incorporation
Mixing temp
Manner of spatulation
Water contamination or loss from liquid
Which traditional cement?
The greater the surface area of powder, the faster the rxn
Zinc phosphate
Which traditional cement?
More rapid incorporation of the powder into the mix will increase surface area of the powder, leading to a faster rxn
Zinc phosphate
Which traditional cement?
A higher powder/liquid ratio will make it set faster
Zinc phosphate
Which traditional cement?
Small initial quantities of powder provide smaller surface area for rxn with the acid
Zinc phosphate
What is the MOST IMPORTANT property of cement?
Solubility
Premature contact of Zinc phosphate cement with water/saliva results in ___________ of the surface, and it will become soft, friable, chalky
leaching
There is a continued loss of Zinc phosphate material in the mouth over time. What 3 things can affect this?
Powder/liquid ratio or mix
Diet
Oral environment (acidity)
Which traditional cement?
Luting mix reaches:
pH of 4.2 in 3 mins
pH of 6 in 1 hr
Neutral in 48 hrs
Zinc phosphate
Which traditional cement?
May cause irreversible trauma to pulp
Zinc phosphate
Which traditional cement?
Ca2+ hydroxide, varnish, or bonding agent should be applied to vital dentin before cement
ZInc phosphate
Which traditional cement?
Shrinks as it hardens
Zinc phosphate
Which cement is not used anymore?
Zinc silicophosphate
Which traditional cement?
Only used as a temporary material because it is highly soluble
ZOE
Which ingredient in ZOE reduces brittleness?
Rosin
Which powder ingredient in ZOE is a plasticizer? Which liquid ingredient in ZOE is a plasticizer?
Powder = zinc stearate
Liquid = olive oil
Which ingredient in ZOE increases strength and setting rxn?
Zinc acetate
What is the main liquid in ZOE and is a sedative?
Eugenol
T/F: ZOE should never be used as a permanent cement
True
What is the setting reaction in ZOE cement?
Chelate
Which traditional cement?
Chemical compound that has primary and/or secondary bonds projecting from 2 sites on a molecule toward a single metal ion; a ring formation results and the cement sets
ZOE
T/F: ZOE bonds to tooth structure
FALSE
Which traditional cement?
A large amount of powder can be added by heavy spatulation
ZOE
Which traditional cement?
Flow is deceptive, and people tend to not add enough powder
ZOE
Which traditional cement?
Flow is viscous compared to Zinc phosphate cement
ZOE
Which traditional cement?
Cool slab is NOT required; treated paper pad is better
ZOE
Which traditional cement?
Cool slab is required
Zinc phosphate
Zinc polycarboxylate
Which traditional cement?
Bulk of powder is incorporated in initial step; thoroughly spatulate
ZOE
Which traditional cement?
Film thickness
Long working and setting times
Low strength
High solubility
Good sealing properties
Pulp protection not needed
Inhibits set of resin
Irritant if in direct contact w/ pulp
ZOE
What is another word for “sedative” that is sometimes used on boards?
Obtundant
Which traditional cement?
Liquid component is a copolymer of polyacrylic acid and itaconic acid
Zinc polycarboxylate
Which liquid component of Zinc polycarboxylate will actually bond to the tooth structure?
Polyacrylic acid
Which traditional cement?
Powder is ZnO and MgO; sintered and ground to reduce reactivity of ZnO
Zinc polycarboxylate
Which traditional cement?
Consistency is thick compared to Zinc phosphate
Zinc polycarboxylate
Which traditional cement?
Thixotropic
Zinc polycarboxylate
Which traditional cement?
Rapid mixing (30 seconds), all at once
Zinc polycarboxylate
Which traditional cement?
Clean, dry cavity; do not varnish cavity; cement must appear glossy
Zinc polycarboxylate
Which traditional cement?
24 hr compressive strength is 1/2 that of Zinc phosphate
Zinc polycarboxylate
Which traditional cement?
Tensile strength is 40% greater than Zinc phosphate
Zinc polycarboxylate
Which traditional cement?
Slightly higher film thickness than Zinc phosphate
Zinc polycarboxylate
Which traditional cement?
Carboxylate groups in the polymer chelate to Ca2+ for adhesion to tooth structure
Zinc polycarboxylate
Which traditional cement?
Adhesion to gold castings is dependent on surface prep (sandblast or electrolytic etching)
Zinc polycarboxylate
Which traditional cement?
Slightly more acidic than Zinc phosphate when first mixed
Zinc polycarboxylate
Which traditional cement?
Acidic penetration into tubules in minimal
Zinc polycarboxylate
Which traditional cement?
Some formulated with SnF instead of MgO for fluoride release
Zinc polycarboxylate
Which traditional cement?
Less soluble than Zinc phosphate in oral fluids
Zinc polycarboxylate
Which traditional cement?
Powder is aluminosilicate glass + fluoride flux
GI
Which traditional cement?
Liquid is polyacrylic acid, itaconic acid, and tartaric acid
GI
What are the 3 types of GI?
Liner/base
Durable filling
Cementing
Which traditional cement?
Strength is 2x that of Zinc phosphate for some types
GI
Which traditional cement?
Anticariogenic
Low solubility once set
Adhesion
Biocompatible
Technique sensitive
Some available in light-cured formulations
GI
Cements based on filled polymers designed to adhere to tooth structure, requiring the use of a separate etching and bonding agent
Adhesive resin cements
Self-etching cements based on filled polymers designed to adhere to tooth structure and other substrates, without the use of a separate etching and bonding agent
Self-adhesive resin cements
These cements are also called “Universal”
Self-adhesive resin cements
These cements may selectively etch enamel margins
Self-adhesive resin cements
Chemical agent used to increase affinity of adhesion to metallic or ceramic materials
Primer
What are the 2 basic categories of polymer-based cements?
Resin-based cement
Resin-based GI
Which category of cement has the following ideal properties?
High bond strength to tooth structure and various materials
High tensile/compressive strengths
Low solubility
Color stability
Low water sorption
Low film thickness
Radiopacity
Tolerance to moisture during cementation
Polymer-based cement
Which polymer-based cement has the following disadvantages?
Technique sensitive; bond strength is affected by pre-tx procedures, depth of cure, degree of polymerization, opacity/shade of restoration and cement
Resin-based
Which polymer-based cement has the following disadvantages?
Difficult clean-up
Change shade during curing
May darken during lifetime
Resin-based
What are the 2 ways to classify polymer-based cements?
Polymerization mechanism
Adhesive scheme
What are the 3 categories of polymer-based cements that fall under polymerization mechanism classification?
Light cured
Chemical cured
Dual cured
What are the 2 categories of polymer-based cements that fall under adhesive scheme classification?
Adhesive resin (bond and either total etch, selective etch, or self etch)
Self-adhesive resin (no etch, no bond)
Which polymer-based cement?
Advantages = increased working time, decreased finishing time, remove excess cement before final curing, color stability
Light-cured resin
Which polymer-based cement?
Chemical and light curing when ceramic is too thick or too opaque
Dual cure resin
Which polymer-based cement?
Has both a self-cured initiator (benzoyl peroxide) and a light-cured initiator (camphorquinone)
Dual cure resin
Light cured and dual cured resin cements can be ______________
tack cured
When doing tack cure, after you seat the restoration, cure marginal excess cement for ___________
2 seconds
When doing tack cure, remove the cured excess with a ____________
scaler
Which polymer-based cement?
Self curing, not as color stable, limited shade selection
Chemical cured resin
Which polymer-based cement?
Requires bond, bonds cement to tooth, self-etching
Adhesive resin
Which polymer-based cement?
Optional phosphoric acid to etch enamel and/or dentin
Adhesive resin
Which polymer-based cement?
May be light or dual cured; highest bond strengths especially to enamel; multi-step technique is complex
Adhesive resin
Which polymer-based cement?
One component, “universal” adhesive
Self-adhesive resin
Which polymer-based cement?
Bonds directly to enamel, dentin, metal, ceramic
Self-adhesive resin
Which polymer-based cement?
Acidic monomers for bonding to different substrates; better bond to dentin than enamel
Self-adhesive resin
Which cement has a better/higher bond strength to tooth structure: adhesive or self-adhesive resin cement?
Adhesive resin
Which polymer-based cement?
Change from acidic to neutral in 24 hrs; pH of 2 after mixing
Self-adhesive resin
Which polymer-based cement?
Ability to self-etch; hydrophilic for interaction w/ moist collagen fibers
Self-adhesive resin
Which restoration would you use the following cements on?
Any cement not requiring light activation; dual cured could work tho
Metallic
Which restoration would you use the following cements on?
A resin cement; resin modified GI would be 2nd choice
ACC
Which restoration would you use the following cements on?
Light cured is preferable to avoid color shift
Porcelain veneer
Which polymer-based cement?
Exhibits fluoride release comparable to true GI cements
Resin-modified GI
Which polymer-based cement?
RelyX Luting Plus
Resin-modified GI
Which polymer-based cement?
Moisture tolerance during cementation
Resin-modified GI
Which polymer-based cement?
Adheres to tooth structure; less soluble than GI
Resin-based GI
Which polymer-based cement?
Expansion after setting due to water sorption; causes crack propagation in ACC
Resin-based GI
Which polymer-based cement?
Prep must be more retentive in design
Resin-based GI
Facebow should replicate the __________ movements of the pt
functional
Facebow should transfer ___________ info that is useful for diagnosis and tx
esthetic
Facebows help minimize time spent _____________ in the chair when seating restorations
adjusting
What does the earbow help with?
Axis of rotation of the mandible
(opening, closing, lateral movements)
Why are posts needed?
Tooth had RCT and does not have enough leftover tooth structure
What are the 5 indications of posts?
- Remaining structure is inadequate for retention of restoration
- Enough root length to accommodate post w/ appropriate apical seal (4-5mm)
- Enough ferrule effect (1.5-2mm)
- Healthy periodontium
- Adequate occlusal function/load
When placing the post, it is important to have an ______________ feature to keep it stable
anti-rotational
What is the main goal of a post? (ON EXAM)
Retain core on prep for fabrication of restoration
T/F: Posts strengthen and reinforce teeth
FALSE
How long should a post be? (4)
Equal or longer than the clinical crown length
2/3 root length
1/2 root length on bone
4-5mm of gutta percha for apical seal
What happens if a post is too short?
Root fracture
Post decements/fails
What happens if a post is too long?
Canal can get contaminated if there’s not enough apical seal
There is no need to place a post longer than ______mm
11mm
What are the 3 types of posts?
Cast metal post (indirect technique; made custom by lab)
Fiber post (direct technique)
Metal post (direct technique)
Before placing a post, you should prep the canal so that there are no ___________
undercuts
Which type of post has flexibility that is similar to dentin?
Fiber post
When should you use a cast metal post that is custom made by a lab?
When there is little to no tooth structure left
A coronal-radicular core buildup utilizing the pulp chamber and 2mm canal extension; proven to be very successful
Amalgam core buildup
Pulp chamber anatomy must provide adequate retention form for this type of buildup, otherwise, a post may be required instead
Amalgam core buildup
Amalgam core buildups are only used for which teeth?
Molars
Band or ring used to encompass the root or crown of a tooth
Ferrule
Provides bracing or casing effect to protect the integrity of the root
Ferrule
Where is ferrule height measured from?
Crown margin to core buildup
How many mm should the ferrule be in order to minimize risk of fracture?
1.5-2mm
T/F: A post is NOT contraindicated if the ferrule height of 1.5-2mm is not met, but it will compromise the prognosis of the tooth
True
When preparing a tooth for any kind of restoration, it is important to place the margin on ______________
sound dental structure
Which appointment?
a. Preliminary impressions, facebow, mounted casts
b. Wax-up if needed
c. Tx plan elaboration
d. Fabrication of vacuum form for provisional fabrication
Diagnosis + tx plan (1 or 2 appts)
Which appointment?
a. Shade selection prior to prep (teeth dehydrate during appt)
b. Anesthesia
c. Prep
d. Evaluate if tooth will need additional procedures (build-up, endo)
e. Provisional restoration fabrication
f. Cement provisional
Crown prep appt
Which appointment?
a. Anesthesia
b. Try-in custom tray/stock tray, paint tray with adhesive, prepare impression material guns. (Remember to always bleed material!)
c. Place 1st retraction cord
d. Evaluate prep, refine if needed
e. Place 2nd retraction cord
f. Impression
g. Interocclusal registration (Regisil)
Final impression appt
A facebow record must always be obtained to mount the ___________ cast on the semi adjustable articulator
maxillary
An interocclusal record should be obtained to mount the ____________ cast
mandibular
This record gives good stability to the mandibular arch when articulated
Interocclusal record
A distribution of contacts with a ___________ layout is desired to maximize stability
tripod
Where should you place the bite reg material?
Only on teeth being restored
Trim the interocclusal record so only the most occlusal _________ digitates into the material
1mm
What material is used for interocclusal records?
Regisil
Aluwax
Dentil bite and impression wax
Aluwax
Composite material with powdered aluminum to increase integrity of compound and provide heat retention properties for efficient modeling
Aluwax
What step does this describe?
a. Pour and fabricate master cast
b. Mounted case w/ facebow and interocclusal record
c. Lab script
d. Faculty signature
e. Turn in case to South Lab to be sent to lab
Lab procedures
Which appointment?
a. Remove provisional w/ hemostat
b. Clean crown prep from all cement excess w/ pumice (Preppies)
c. Try-in crown
d. Cement crown w/ appropriate cement and respective manipulation
technique
e. Remove all cement excess
f. Verify restoration was fully seated, check occlusion, interproximal contacts…
g. Final x-ray: verify all margins are closed and crown fully seated
Crown delivery appt
Which step of the crown delivery appt?
- Check margins clinically, should be closed.
- If margins are opened, check for very heavy inter-proximal contacts - they might not be letting the restoration seat completely
- If margins are clinically closed take a bite-wing x-ray (posterior teeth) to verify closed margins
- If margins appeared opened radiographically, check for very heavy interproximal contacts.
- Once the close margins are confirmed, check interproximal contacts.
- Last adjustment, occlusal surface on MIP and eccentric movements
- Polish porcelain with the Dialite Porcelain Polisher Kit to minimize occlusal wear of opposing dentition.
Try-in
Which step of the crown delivery appt?
1.Verify margins, inter-proximal contacts, occlusion, shade, xray…
2.Wash crown from any debris (Ivoclean or phosphoric acid)
3.Clean abutment from any previous cementation, saliva, blood…
4.Cementation:
Every cement has it’s own cementation instructions. Read them, follow them
4.Let cement fully set / light cure. (Remove gross excess when
partially set)
5.Gently remove cement excess with an explorer. Assistant helps with high suction.
6.Verify margins and occlusion with shimstock for any last adjustments. Always polish after adjustments with the dialite polisher kit!!!
7.Final x-ray, verify all margins are closed
Cement permanent crown
Which polisher kit is used to polish crowns after adjusting?
Dialite
What is the order of checking the fit of a crown or FDP in the pts mouth?
- Margins
- Interproximal contacts
- Occlusion
Which step of crown prep appt?
- Clean provisional from any previous cementation or debris.
2.Clean abutment from any previous cementation, saliva, blood…
3.Cementation:
Assistant: mixes and loads provisional with provisional cement.
Dentist: isolates tooth and lightly dries the tooth. Then, seat restoration
after handled by assistant.
4.Let cement fully set.
5.Gently remove cement excess with an explorer. Assistant helps with high
suction.
6.Verify occlusion, provisional restoration could have not seated
completely.
Cement provisional
Which provisional cement?
Crowns
FDPs
Inlays/onlays
Non-eugenol cement
Which provisional cement?
Inlays/onlays
Implant screw access
Light cure composites
T/F: Eugenol containing bases and liners partially inhibit polymerization of freshly mixed composite restorations and there is softening of the resin surface adjacent to the eugenol liner
True
Light cure composites have a _________ consistency when fully cured
rubbery
Which provisional cement?
Considered a permanent cement, but can be used for long term provisional cementation
Polycarboxylate luting cement
Which provisional cement?
Durelon
Polycarboxylate luting cement
Which provisional cement?
Used when provisional doesn’t successfully retain with a provisional cement
Polycarboxylate luting cement
Which provisional cement?
Used when a pt will be out of town for a few weeks
Polycarboxylate luting cement
Formulated w/ 2.0% CHX gluconate for cleaning and disinfecting
Preppies pumice paste
What is the thickest articulating paper?
Horseshoe articulating paper
What is the thinnest articulating paper?
Shimstock
Which articulating paper?
181.7 um thick
Horseshoe
Which articulating paper?
25.5 um thick
Accu Film II
Which articulating paper?
9.2 um thick
Shimstock
Which articulating paper?
Double-sided for precise occlusal equilibration and restoration adjustments
Accu Film II
Which articulating paper?
Won’t trigger mandibular reflexes that might skew bite
Accu Film II
Which articulating paper?
Consistently produces sharp, easy to interpret marks; no false markings
Accu Film II
Which articulating paper?
Stretches, but does not break; no snap back to distort marks
Accu Film II
Which articulating paper?
Highest plastic deformation of all major brands tested
Accu Film II
What should you do when equilibrating hard to mark surfaces like polished gold in order to read Accu Film II marks?
Apply thin coat of vaseline
In the dialite polisher kit, what is the level of grit for the blue, pink, and gray polishers?
Blue = coarse
Pink = medium
Gray = fine
(use in order!)
The dialite polisher kit is best used on which type of crown material?
Feldspathic porcelain
What is the recommended speed when using the dialite polisher kit?
5000-8000 rpm
Which part of the dialite zirconia polishing kit?
Adjust occlusal surfaces of posterior teeth and lingual surfaces of anterior teeth
Football diamond
Which part of the dialite zirconia polishing kit?
Adjust cusps and interproximal contacts
Tapered diamond
Which part of the dialite zirconia polishing kit?
Adjust fossa
Round diamond
Which part of the dialite zirconia polishing kit?
Using light pressure and no water, prepolish with blue polisher to remove abrasions left by diamonds during adjustment
Dialite polisher (blue)
Which part of the dialite zirconia polishing kit?
Can also be used alone for minor adjustments if you don’t want to use a diamond
Dialite polisher (blue)
Which part of the dialite zirconia polishing kit?
Continue pre-polishing until glossier look appears on adjusted areas
Medium polisher (green)
Which part of the dialite zirconia polishing kit?
Use with light/medium pressure to achieve a “wet” high shine
Fine polisher (orange)
Which permanent cement?
Self-etching dual cure resin cement
Rely x Unicem
Which permanent cement?
Used to cement any material, but avoid on areas where isolation is difficult; resin materials don’t work well under moisture
Rely x Unicem
Which permanent cement?
Comes in different shades for cementing translucid materials (veneers, ACCs)
Rely x Unicem
Which permanent cement?
Avoid w/ veneers or highly translucid restorations, since dual cure cement shades can change over time
Rely x Unicem
Which permanent cement?
Resin modified glass ionomer cement
Rely x Luting
Which permanent cement?
Crowns and FDPs:
PFM, FMC, PFZ, zirconia
Rely x Luting
Which permanent cement?
Inlays/onlays:
Metal
Rely x Luting
Which permanent cement?
Cast metal post and core
Rely x Luting
Which permanent cement?
Avoid cementing any lithium disilicate, feldspathic, or composite restorations
Rely x Luting
Universal cleaning paste to clean bonding surface of restorations after intraoral try-in; creating optimum pre-requisites for adhesive luting procedure
Ivoclean
Which step of cast metal post appt?
- Prepare tooth to desired working length and canal width.
- Canal Final Impression using impression plastic post (smooth post).
- Fabricate provisional restoration using the titanium post and Jet Acrylic
1st appt
Which step of cast metal post appt?
- Pour final impression and place burnout post on master cast.
- Wax-up post & core on burnout post. Sprue, invest and cast post
Lab procedures
Which step of cast metal post appt?
- Try-in / Cement cast metal post. (I recommend cementing with the Rely
X Lutting Plus). - Refine crown preparation, final impression and crown cementation
2nd appt
Aerosol spray for disclosing high spots and contact points
Occlude
Useful when seating crowns and cast metal posts if not seating properly
Occlude
Dries instantaneously; adheres to dry or moist surface
Occlude
If gypsum materials are immersed in water during setting, the setting expansion will ____________
increase
All gypsum material __________ on setting from growth of crystals
expand
Which gypsum expands the most on setting?
Plaster > dental stone > die stone
What will result in a gypsum with the following qualities?
Thinner mix
Longer setting time
Weaker
Less expansion
Increased water/powder ratio
What will result in a gypsum with the following qualities?
Thicker mix
Shorter setting time
Stronger
More expansion
Decreased water/powder ratio
The longer the mixing time, the ____________ the setting time, and the _____________ the expansion
shorter; greater
Impression plaster
Type I
Model plaster
Type II
Dental stone
Type III
Die stone or high strength stone
Type IV
Die stone (high expansion)
Type V
Inlay, thermal
Type I
Inlay, hygroscopic
Type II
Partial denture, thermal
Type III
_____________ expands more at lower temp
Cristobalite
________ form is stable at room temp
Alpha
________ form is stable at high temp
Beta
Prevents O2 from contacting metal and causing oxidation; dissolves oxides already present
Flux
