Dental Materials Final
How long should you mix gypsum products?
1 minute
How does an auto-cured material harden or set up?
An auto-cured material hardens, or sets up, through a chemical reaction of the materials being mixed together.
Gypsum has reached its final set when it is strong enough to handle and has lost its gloss.
False (initial set)
All elastomeric impression materials can be submerged in a disinfectant solution.
False, Polyether cannot be submerged in disinfectant
What variable affects the addition or loss of water in a dental cement?
Humidity
Which filler type of composite resin is recommended because of its versatility?
Hybrid resin
Aluwax is classified as:
Impression wax
Which gypsum product would I use to pour study models?
Lab plaster
Define syneresis.
Loss of water which causes materials to shrink and distort. Caused by exposing materials to air for an extended period of time.
What is the easiest method to soften wax?
Water bath
Which material is applied first—the bonding or etchant material?
etchant
In the composite resin cementation procedure, what step is important to complete on the tooth surface before cementation of the material?
the tooth must be free of all plaque and debris and must be prepared by etching or by treatment with a bonding system
How is TempBond supplied?
two tubes of paste
What could contaminate the setting of glass ionomers?
water
Can glass ionomer cement be used as a restoration material?
yes
Can resin cements be used under metal castings?
yes
What are the order of the tanks in a hydrcolloid conditioning unit?
1. Boiling tank 2. Storage tank 3. Tempering tank
In increasing order of viscosity, list the forms of elastomeric impression materials. (lightest to heaviest)
1. Light body (syringe material) 2. Regular body (either tray or syringe) 3. Heavy body (tray material) 4. Putty (most viscous, tray material only)
Identify terms associated with alginate: 1. Mixing time 2. Working time 3. Setting time
1. Manufacturer states how long to mix 2. Time to mix alginate, load tray, and position in mouth 3. Time from beginning of mix until material is completely set
What variables can affect the setting time of alginate impression material?
1. Water temperature 2. Spatulation rate 3. Use of normal or fast set alginate 4. Addition of accelerators and retarders 5. Room temperature and humidity 6. Water and powder ratio
How many drops of monomer per tooth are recommended when acrylic resin is mixed for a provisional restoration?
10
What dental instrument is used to adapt a base into the cavity preparation?
A condenser
What happens to a dental material when it is exposed to hot and cold?
A dental material undergoes contraction and expansion when it is exposed to hot and cold.
What type of reaction does a dental material undergo when distortion occurs?
A dental material undergoes stress when distortion occurs.
What ingredient in the powder of glass ionomer cement helps to inhibit recurrent decay?
Acid-soluble calcium slowly releases fluoride
What material would you use to prepare for provisional coverage?
Acrylic resin or composite resin
How do I incorporate the water and powder of gypsum?
Add the powder to the water in a rubber bowl.
Where do you dispose of amalgam scraps?
Amalgam scraps are placed in a wide-mouthed, air-tight container marked "Noncontact Amalgam Waste for Recycling". When the container is full, it is sent to a recycler
What professional organization evaluates a new dental material?
American Dental Association (ADA
What is the common term used for dimethacrylate?
BIS-GMA.
If you want to alter the setting time for alginate, what method is best?
Change the temperature of the water
Reversible hydrocolloid impressions are primarily poured with which gypsum product?
Class II stone
The DDS wants you to pour the impression with the strongest of the gypsum products. Which one would you use?
Class II stone
What type of gypsum product would you most likely use to pour an elastomeric impression with?
Class II stone
Which gypsum product would you use to make a die or master cast (more than just the die, included teeth around the die)?
Class II stone
If i want to increase the setting time of a gypsum product, would I use colder or warmer water?
Colder
What does copper provide to an amalgam restoration?
Copper provides strength and corrosion resistance to amalgam.
This impression tray is made for only one individual. It makes a more accurate detailed impession.
Custom tray
Who in the dental office can legally take a final impression?
Dentist
When composite resins are light-cured, what factors might contribute to the need for a longer curing time for the material?
Depth of restoration and color might contribute to the need for a longer curing time.
The best choice for an extremely accurate impression material is: 1. Elastomeric 2. Alginate
Elastomeric
What is die and what is it poured with?
Exact reproduction of a tooth or teeth which has been prepared for a crown, bridge, inlay, or onlay. Pour with Class II stone.
An impression is a positive reproduction of the patient's teeth.
False
It is recommended that when you mix gypsum products you use a whipping action.
False
One use of a preliminary impression is a working model to construct a partial denture.
False
The greater the amount of water needed for a gypsum product the stronger the product.
False
The shelf life of alginate materials is approximately 5 years.
False (1 year)
A fold in an impression is caused by movement?
False (drag)
Bite wafer wax is classified as:
Impression wax
If I can't pour an alginate impression right away, how should I store it, and for how long (ideally)?
In a humidor, pour within an hour
If I am not able to invest a wax pattern right away, how should it be stored?
In the refrigerator
Which wax requires a flame for manipulation?
Inlay wax
The gypsum product you are working with has particles that are rough, randomly shaped and require more water. What is it?
Lab plaster
Baseplate wax is classified as:
Pattern wax
Casting wax is classified as:
Pattern wax
Which of the following materials has the longest setting time? 1. Polysulfide 2. Polyether 3. Silicone
Polysulfide
This impression material can be held up to 7 days after it has been taken and poured.
Polyvinlysiloxane
Boxing wax is classified as:
Processing wax
Sticky wax is classified as:
Processing wax
What is the main ingredient in varnish?
Resin
Which impression material requires the use of a water-cooled tray?
Reversible hydrocolloid
What is a source of galvanic action?
Saliva (salt conducting electrical currents) and two metals (acting as battery) are sources of galvanic action.
What kid of wax might I use to temporarily hold something together?
Sticky wax
What precautions are taken when storing gypsum powder?
Store in an airtight container in a cool dry place
What is dimensional stability referring to?
The ability of a material to keep its shape after it has been removed from the mouth
What must be removed from the tooth structure for bonding material to adhere to dentin?
The smear layer
When pouring an impression, where is the gypsum added to the impression?
To the heel of the impression
Is putty material placed in the tray or the syringe?
Tray
Bite wafer wax is used to take bite registrations for dentulous patients.
True
The dentist would most likely use reversible hydrocolloid impression material for crowns, bridges, inlays, or onlays.
True
The putty-wash technique requires two impressions of the same area.
True
The regular body elastomeric impression material, polyether, can be loaded in both the tray and the syringe.
True
What type of ZOE is used for permanent cementation?
Type II ZOE
What causes a grainy texture in alginate impression materials?
Under-mixing
Define imbibition.
Uptake of water (by hydrocolloid impression materials)
What is a working cast and what is it poured with?
Used for fabricating dentures, partial dentures, retainers and custom trays. Pour with Class I stone.
What is a study model and what is it poured with?
Used for orthodontics and consultation appointments. Pour with lab or model plaster
What kind of wax is this? Wax that goes along the outer edge of the impression tray.
Utility/periphery wax
What is the main ingredient in hydrocolloid impression materials?
Water
What are two other ways to minimize distortion of waxes?
a. Avoid temperature extremes b. Manipulate as little as possible
which materials is varnish contraindicated?
composite resins and glass ionomer restorations
What are the four properties that must be considered in the application of a dental material?
flow, adhesion, retention, and curing.
What is the toxic element in a desensitizer?
glutaraldehyde,
What are the three noble metals used in dentistry?
gold, palladium, and platinum.
What type of restoration is made in the dental laboratory?
indirect
What does the abbreviation IRM stand for?
intermediate restorative material.
What is another name used for permanent cement?
luting agent.
varnish be placed under all restorative materials?
no
On what mixing surface is ZOE mixed?
oil-resistant paper pad or a glass slab.
Where is a base applied in the preparation?
on the pulpal floor.
What is an example of enamel bonding?
placement of sealants, orthodontic brackets, bridges, and veneers
In what two forms is the polycarboxylate cement liquid supplied?
powder or liquid.
What are the unique qualities of calcium hydroxide?
protects from chemical irritation, stimulates production of reparative dentin, is used for pulp capping of pulpal exposures and near exposure, and is compatible with all materials.
What is the function of a dental liner?
protects the pulp from irritation
What does an insulating base provide for the restoration of a tooth?
protects the pulp from thermal shock.
When is a temporary cement used instead of a permanent cement?
provisional coverage , temporary cementation
What are some of the most common uses of glass ionomer materials?
restorative materials, liners, bonding agents, and permanent cements.
How could IRM be utilized in a pediatric practice?
restore primary teeth that are about to be replaced by permanent teeth
What does a desensitizer do?
seals the dentinal tubules to protect the tooth from hypersensitivity.
What metals make up the alloy powder in amalgam?
silver, tin, copper, and zinc.
