-
What are the two types of flexible impression materials?
- Hydrocolloids
- Elastomerics
-
What is the reversible hydrocolloid?
Agar (no bowl needed)
-
What is a model used for?
It's a replica to Study oral anatomy.
-
What is a cast used for?
Working replica used for fabricating appliances.
-
What is a Die used for?
Working replica of one tooth used.
-
Which impression material has the least amount of detail?
Alginate
-
What is the weakest part of a dental bridge?
The cement
-
How does dental Amalgam set up?
By crystallization
-
How does impression material set up?
By Polymerization
-
What comes out of gypsum pancakes and what is used for?
Gauging water and it's just a lubricant
-
What is the One rule for dental materials?
Don't Assume Anything!
-
How do you remove Alginate?
With a snap
-
What are thermal conductors?
Metal things
-
What is wetability?
Resistance to flow
-
Which material do you Vacuum form?
Polyethylene
-
What is used to polish a gold crown?
Jeweler's Rouge (iron oxide)
-
Which liner is universal?
Ca(OH)2; calcium hydroxide
-
Who does OSHA worry about?
The workers
-
Does Alginate shrink?
Yes; syneresis
-
How do you mix alginate?
To a homogenous mixture.
-
How dental implant placed?
osseointegration
-
A secondary container needs to be used when and have what?
After 8 hours; needs a label that is xeroxed or handwritten.
-
Which Impression do you do first and why?
Mandibular first, less likely to gag.
-
Who provides the MSDS and what does it stand for?
The manufacture provides and it stands for Material Safety Data Sheet.
-
Who and when do you need hazardous training?
New employees, if there are any changes it directions, and when there is new products introduced.
-
Gypsum is what type of dental material?
A ceramic
-
How do you place Composites?
They shrink is must place in increments
-
What material is used for denture to be placed on a Low Alveolar Ridge?
PMMA
-
For dentures what material is used for a High Alveolar Ridge?
Porcelin
-
Which cement is NOT used under composites?
ZOE
-
When trimming models what do you start with?
The Maxillary Arch
-
Can age determine whitening?
Yes
-
When mixing liquid/powder ratio depends on what?
intended use and manufacture instructions
-
True or False. With Dental Material you want thermal conductivity.
False
-
Define Retention
Capacity of restorations & replacements to stay firmly in place.
-
Define Adhesion
Force that causes Unlike molecules to attach.
-
What is Cohesion?
Attraction of same kind of molecule.
-
What is Tensile Force?
The force moving away
-
What is compression?
The forces moving into the object
-
Define Ductility
Tensile stress w/o fracture
-
Define Percolation
Bubbling of fluids between solids.
-
What is casting?
Shaping by melting and forming
-
What is wroughting?
Shaping by twisting or bending
-
What is Gypsum?
A mineral CASO4 x 2H2O (calcium sulfate dihydrate)
-
What are the steps to mixing and pouring gypsum?
- Step 1: 50ml of water in a bowl and sift 100g of plaster and let sit of 5 seconds
- Step 2: wet all powder and then spatculate until homogenous mixture
- Step 3: Zing zing on the vibrator
- Step 4: Pour in one corner using the same corner each time you add some while zinging it on the vibrator.
-
Characteristics of Plaster
- Dry calcined hemihydrate, beta hemihydrate
- Crystals: spongy, porous, irregularly shaped.
- Low strength
- Low abrasion resistance
- Increased gauging H2O
-
How do you alter the setting time of Alginate?
By using cold water to slow it down and warm water to speed it up.
-
What materials have a Exothermic Reaction?
-
Characteristics of Stone
- Autoclaved hemihydrate
- Alpha hemihydrate
- Crystals: Prism shaped,denser
- Higher strength
- Higher hardness
- Less gauging H2O
-
Characteristics of High Strength Stone
- Densite, Modified Alpha- Hemihydrate
- Dense
- Stubby
- Crystals: Spheres, cubes
- Least H2O added
-
How does plaster and stone set up?
Crystallization
-
What are some plaster accelerators?
Salt and K2SO4
-
What are the plaster retarders?
Borax, cold water, and citrate
-
What are abrasives?
Hard particles that abrade a softer surface (substrate).
-
MOH Scale
- Measures Hardness
- Diamond 10
- Al2O3 9
- Porcelain 6-7
- Tin Oxide 6-7
- Pumice 6
- Rouge 5-6
- Composite 5-7
- Enamel 5-6
- Gold Alloy 3-4
- Dentin 3-4
- Gypsum 2
- Acrylic 2-3
-
If you increase the liquid/powder ratio of cement it's what?
More soluble, less strong.
-
What part of an implant protect from bacteria?
periomucosal seal
-
What is one thermoplastic?
Gutta Percha
-
Base Metals
- CO-Cr
- Cr-Ni
- stainless steel
- Ti
-
-
Amalgam with Cu
Gives High strength, resistance to corrosion, and hardness
-
Amalgam with Ag (silver)
High Luster
-
Amalgam with Sn (Tin)
Reduces expansion, strength, hardness, and WORKABILITY
-
Amalgam with Zinc
Scanveger
-
Bonds can be what?
- Composites
- Veneers
- Sealants
-
True or False: Titanium is a reactive material, but not in the body.
True
-
What are some ceramics?
- Porcelain
- Zinc Oxide
- Glass ionomers
- Silica: SiO2
- Kaolin
- Zirconia
-
Which cements bond to the tooth?
- Glass ionomer
- Polycarboxylate
-
ZOP
- Permanent Luting Agent
- Thermal Insulating Base under deep amalgam restorations
-
ZOE
- Uses include Base, Temporary Luting , Temporary Restorations.\
- Soothing, OBTUNDENT to pulp
-
Polycarboxylate
- Not as strong as ZOP
- Less irritating that ZOP
- Bonds to the tooth
-
Glass Ionomer
- Used as permanent luting and permanent restorations( comes in blendable shades)
- Fluoride leaches out of the powder into the tooth structure
- Chemically bonds to tooth structure (bonds to Ca++ in the tooth)
- Used for lots of things
-
Intermediary Materials
Materials placed between the tooth and the main restorative material
-
What is the most commonly used Liner?
Ca(OH)2
-
What are varnishes used for?
Seal dentinal tubules
-
Polysulfide aka Mercaptan
- Smells strong.
- Pour ASAP or at least within 30 min.
-
Polysiloxane
Should be poured ASAP
-
Polyvinyl Siloxane
- Cannot wear latex gloves because contact may retard the setting time of the vinyl.
- Should be poured within 2 week
-
Polyether
Should be poured within 2 week period
|
|
