Midterm Flashcards
The part of an FPD that is not directly on any tooth structure is called the ______.
Pontic
The __________ tooth is the one which is prepped to support the FPD.
Abutment
A __________ is any type of device used for the stabilization or retention of a prosthesis.
Retainer
T/F: It is important that the patient can clean and pass floss under the pontic.
True
If the decay is at the JE, what must be done before the preparation in order to not violate the biological width?
Crown lengthening
What are the primary factors for retention?
- Proper taper
- Proper length
- Proper width/surface area
What margin design is indicated for a metal-ceramic crown with a disappearing metal collar?
Sloped shoulder
What are some disadvantages of the disappearing collar and sloped shoulder?
- Difficult prep
- Greater creep
- Rough margin area
- Potential gray line
- Can be overcontoured
Which type of margin gives optimum esthetics?
Butt
What are some absolute indications for a butt margin?
- Minimal sulcus depth of less than 1 mm
- Thin labial tissue
- High smile line
What is Ante’s law?
Determines what types of FDPs will be successful based on the root surface area of the abutments
Which teeth have the highest root surface area?
Canines and molars
Which types of ceramics are used for denture teeth and porcelain jacket crowns?
High-fusion and medium-fusion
Which types of ceramics are used for metal-ceramic crowns?
Low-fusion and ultra low-fusion
Feldspar is a naturally occuring glass that contains what three compounds?
Silica
Fluxes
Alumina
Feldspar, quartz, and other oxides are heated and rapidly cooled which causes the glassy matrix to fracture into many small fragments causing a ______.
Frit
Zinc oxide is contained in _______-fusing porcelain.
Medium
_______-fusing porcelain has the highest percentage of silicon oxide.
High
________-fusing porcelain has the highest percentage of aluminum-oxide.
Medium
What are the steps for preparing the metal surface for porcelain application?
- Clean with cleaning solution in ultrasonic cleaning unit (5 min)
- Clean with distilled water in ultrasonic cleaning solution (5 min)
- Do not touch after cleaning
- Oxidation
Which enamel for MCC is most translucent?
Incisal/Enamel porcelain
During oxidation of the metal, should it be done under a vacuum?
NO
In an MCC, in what order is the porcelain applied to the metal?
Opaque -> body -> enamel/incisal
T/F: Adjustments to the porcelain should be made with the low-speed hand piece after the first bake.
True
What must be done before the seconds bake?
- Clean crown in distilled water in ultrasonic unit for 10 min
- Add porcelain to deficient areas
What are the advantages to a porcelain margin?
- Improved esthetics
2. Less plaque retention
What are the disadvantages to a porcelain labial margin?
- Generally inferior marginal adaptation
- Decreased strength
- More time consuming
- Slightly more expensive than MCC
What is the direct lift technique?
A quick way to add porcelain to the margin of the prep
What is the number one cause of failed FPDs?
Caries
What are four key points to creating optimum occlusion with FPDs?
- Minimize sliding contacts
- Establish anterior guidance
- Opposing contacts in same material
- Control parafunction
T/F: The occlusal contact should be at least 1.5mm from the metal-porcelain junction.
True
What is required for porcelain to bond to metal?
A thin layer of oxide
Why would an adhesive failure between metal and porcelain occur?
No oxide layer
T/F: Cohesive failure in metal is common.
FALSE
What causes cohesive failure in metal oxide?
Excessive oxidation
What are the five keys to framework design?
- Even porcelain thickness
- Rounded internal angles
- 90 degree metal/porcelain junction
- Porcelain wrap-around
- Metal thickness of .3 mm
