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27 Cards in this Set
- Front
- Back
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Pros of PFM
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provide for esthetic veneer
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cons of PFM
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potential for wear, fracture and pulpal problems
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PFM restoration layers
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incisal
body opaque metal |
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function of metal substructure
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marginal adaptation and strenth
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function of opaque porcelain layer
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bonds w/ metal and masks metal color
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function of body/incisal porclain
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esthetics and countour
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guidelines for PFM tooth reduction
Gingival facial incisal lingal |
Gingival = 1.3-1.5 mm
facial = 1.5-1.8 mm incisal = 2.0 mm lingal = 0.8-1.3mm |
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steps to PFM construction
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1. prep tooth, impress, working cast
2. wax metal substruct, cast in PFM allow, trial seat on die 3. oxidize alloy, apply opaque porcelain 4. body incisal porcelain, contour, occlude, deliver |
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list 4 kinds of PFM designs
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full porcelain
facial veneer porcelain facial window partial facial window |
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describe full porcelain coverage
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all contacts porcelain...incisofacial porcelain
INTERMEDIATE strength |
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facial veneer porcelain
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metal contacts
porcelain incisofacial WEAKEST PFM DESIGN |
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facial window porcelain
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metal contacts
incisofacial is metal STRONGEST |
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partial facial window design
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metal present (on incisal) where functional occlusal contacts are
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__ and __ dictate frame design
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location of centric and occlusal contacts
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T or F:Functional occlusal contacts should NEVER cross the porcelain / metal junction (roughest part
of the PFM crown); therefore, put functional movements either all in metal or all in porcelain |
TRUE
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functional occlusal movements occur w/ __ mm of ___
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3 mm of MI
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porcelain/metal junction should be at __ degree angle for strength and to minimize ___
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90 to minimize opaque exposure and increase strength
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what is the dimension of the metal substructure on the lingual of an anterior tooth
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1 mm
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what is the dimension of the metal substructure on the facial of an anterior tooth
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0.3mm
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what is the dimension of the metal substructure on the angle of axial and gingival wall of an anterior tooth
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0.5mm
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what is the dimension of the metal substructure on the gingival floor of an anterior tooth
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0.3mm
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requirements for successfull metal ceramic restoration (4)
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1. accurate abutment castings and ease of casting
2. accurate soldering and ease of soldering 3. rigidity of the metal frame 4. ability of the porcelain to fuse to the metal |
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requirements for successfull metal ceramic restoration (other 4)
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5.adequate strength of final restoration
6. esthetic appearance 7. tissue tolerance 8. ease of repair |
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primary functions of metal ceramic substructure (4)
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1. provides fit of restoration to prepped tooth
2. metal oxide formation to bond chemically to dental porcelain 3. rigid foundation to which brittle porcelain can bond for increased strength and support 4. restore tooth's proper emergence profile |
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secondary functions of metal ceramic substructure
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1. metal occlusal and lingual articulating surfaces
2. metal axial wall can support compoents of RPD 3. axial surfaces can house attachments for fixed and RPDs |
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list some things you should consider when designing a substructure (5)
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1. occlusal contacs in metal or porc.
2. centric occl. contacts 1.5-2mm from porc-metal jnctn 3. prox contacts in metal or porc 4. cusps tips have no more than 2mm of unsupported porc 5. substruct thick enuf to provide rigid foundation for the porc. veneer |
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Porcelain strength—key point: porcelain should never be >__ mm in thickness at any location in a prosthesis
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2.0mm
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