WorksheetsClinical Aspects of Dental Materials Ch 11 Metals and Alloys
Total questions: 34
Worksheet time: 40mins
A compound that is made up of two or more elements, of which at least one is a metal.
Pure metal
Alloy
Solder
Annealed metal
Metal casting alloys are classified as all except which of these?
Base metal
Noble metal
High noble metal
Precious metal
The main reason alloys are used more than pure metals in dentistry:
Low resistance to tarnish
Lower melting point
Higher strength and hardness
High thermal expansion
The amount of gold needed for an alloy to be considered "high noble."
40%
60%
25%
Less than 25%
True or False: Noble metals are better than base metals for all restorations.
True
False
When metal is heated it:
Contracts
Expands
Remains the same
True or False: Base metals typically have higher yield strength than gold alloys.
True
False
Palladium is added to gold alloys to:
Raise melting temperature
Eliminate oxidation
Reduce corrosion and tarnish
Improve yield strength
Which element is seldom used in gold alloys?
Iridium
Gallium
Tin
Nickel
Why is silver a poor metal choice for a cast restoration?
High cost
Liquid at body temperature
Tarnish and corrosion in oral cavity
Low strength
Which of the following is not considered a base metal?
Tin
Copper
Titanium
Platinum
True or False: Nickel has low biocompatibility.
True
False
Which of the following is NOT an important property of porcelain bonding alloys?
Oxidization of the surface
High thermal expansion
Low thermal expansion
High melting range
Which type of crown requires the MOST tooth reduction for proper fit and function?
Full ceramic crown
Full gold crown
PFM crown
All require the same amount of tooth reduction
True or False: in order for porcelain to bond to the metal coping, the metal must be heated at high temperature to oxidize the surface.
True
False
Why do porcelain bonding alloys require an oxidation layer?
Form mechanical bond with porcelain layer
Changes the color of the alloy
Makes the alloy stronger
It does not require an oxidation layer
Porcelain will crack as the metal and porcelain cool if:
The porcelain is not glazed immediately
The porcelain cools faster
The thermal expansion is not compatible
The metal is not oxidized properly
The most esthetic PFM crown design is:
Metal occlusal and porcelain buccal
Metal collar
Knife edge margin
Porcelain facial margin
Gingival recession around a PFM margin can cause:
Dark line at the gingiva
High risk for caries
All of the above
True or False: Titanium is a noble metal.
True
False
Titanium is hard to work with because of:
High melting temp
Low thermal expansion
Low hardness
Corrosion risk
True or False: Sintering requires heating layers of powdered alloy and pressing them together.
True
False
True or False: Base metals should never be used for partial denture frameworks.
True
False
The most important quality of a base metal in denture frameworks is:
Corrosion resistance
Hardness
Resistance to deformation (yield strength)
Low thermal expansion
What alloy is the most resistant to fatigue in denture frameworks?
Nickel-Chromium
Nickel-Titanium
Cobalt-Nickel
Cobalt-chromium
True or False: IdentAlloy certificates are a legal document that should go in the patient's chart.
True
False
Which of these is NOT included on the IdentAlloy certificate?
ADA Classification
Alloy Composition
Manufacturer
Allergy Warnings
True or False: Soldering wire has to melt at a lower temperature than the metal it is connecting to.
True
False
What properties of alloys change when a metal is wrought?
Corrosion resistance and hardness
Hardness and yield strength
Color and melting range
Thermal expansion and hardness
Which of the following dental materials is NOT created with wrought metal?
Orthodontic wire
Preformed stainless steel crowns
Endodontic files
Crown and bridge coping
Why is NiTi wire used in orthodontics?
Cost
Corrosion resistance
Strength
Resistance to deformity
What type of metal are orthodontic bands made from?
Stainless steel
Aluminum
Titanium
Nickel
What are endodontic files made out of?
Cast metal alloys
High noble alloys
Aluminum
Wrought metal alloys
The stiffness of stainless steel is not desirable for endodontic files because:
More flexible than NiTi files
Removes more dentin in curved roots
Faster fatigue
More likely to fracture
