Principles of Tooth Prep II Flashcards
Finishline qualities
- Definitine- you can see and feel it
- Regular- no abrupt changes in elevation
- Continuous
- Conservative appropriate axial depth
- Favorably shaped accomodates material needed
- Favorably located addresses clinical factors
What is a slanted shoulder finish line used for
facial margin of MCC
What is feather edge margin avoided
Although conservative it doesn’t provide adequate bulk at the margins –> overcontour restoration
Should you place a bevel on your shoulder margin? Why or why not
no was once thought that is diminished marginal discrepancy but it doesn’t.
- Also allowed burnishing the restoration margin against the tooth
- Removal of unsupported enamel
- However now with cement is now was causes the greater marginal discrepancy
What is a deep chamfer finish line used for
PFM (dissapparing metal margin)
Some all ceramic margins
Modified shoulder bur used for what margins
- ACC
- Labial margin of PFM (porcelain butt margin)
What is the most common margin
disappearing metal margin
Is there metal showing in disappearing metal margin
yes
Metal color margin requires what burs
chamfer
deep chamfer?
Dissappearing metal margin requires
Deep chamber
slanted shoulder
Ceramic margin required what burs
shoulder
radial (or modified) shoulder
deep chamfer
What are the concerns with disappearing metal margin
- Unpolished metal - rough
- Opaque porcelain- rough
- Porcelain
May jeopardize the health of gingiva
-Often reduction is inadequate –> overbulked restoration
Advantages of supragingival margin
- better gingival health
- Easier tooth prep (and likely better)
- Easier and better provisional)
- Impression= easier
- Patient oral hygiene= easier
- Restoration eval= easier
- Restoration repain= easier
T/F Subgingival margins are major etiologic factors in perio disease
t
Reasons to place a subgingival margin
- Esthetics
- Maximize ferrule
- Place finish line on sound tooth structure
- Maximize retention
- Root sensitivity
- Cervical erosion
- root fracture
