L12/13 Tribology and Finishing and polishing
How do you want to use finishing strip?
S-shape (not C_
What does overpolishing do?
creates stress that results in marginal gap
Which will wear first? diamond, enamel, or dentin?
dentin, enamel, then diamon
What is harder? diamond or discs?
diamond (10 Moh) disc aluminum oxide is only 9 Moh
diamond = enamel = dentin =
diamond = 10 Moh enamel = 5 Moh dentin = 3 Moh
If you want to polish inside grooves and fissures, what can you use?
jiffy brush with firm pressure, high RPM
More diamond = ____ abrasive
less
You want to use astropols with ______ and ______ RPM
low pressure, low RPM
What is polishing??
make surface smooth and shiny
_____ carbide flutes = smoother
more
The greater the number of flutes = ________ aggressive
more flutes = less aggressive
discs can be what material?
mylar plastic or paper
astropol HP
pink (polish)
What is 1. gross finishing?
removal of gross excess composite use coarse grits
What is 3. fine finishing?
removal of scratches and defects DOES NOT ALTER SHAPE
What happens if you use finishing strip in C shape?
removes contact
Astropols are ____ polishing system
rubber
_______ diamond = smoother
smaller
What is 4. polishing?
smooth, luster or shine
What is tribology?
study of friction or wear
eating is _____ body abrasive wear
three body
go from ____ to restoration
tooth to restoration
Two-body abrasive wear
toothbrush on tooth
three body abrasive wear
toothbrush, toothpaste on tooth
brushing is ____- body abrasive wear
two body
Why does composite have slightly lower Moh than enamel?
you dont want to wear away tooth structure you can always replace composite
What do you use to contour interproximal areas?
1. #12 blade 2. disc 3. finishing strip
Steps for finishing and polishing?
1. gross finishing 2. contour 3. fine finishing 4. polishin
Why do we finish and polish?
1. remove excess material 2. contour 3. reduce imperfections 4. smooth
What is the hardness of diamond?
10 Moh's
You would use finishing strip for class _____
2, 3
What is the last step that alters the shape of the restoration?
2. contour step establishes final outline and functional form and smooth CSM
How do you use the disc for facial contouring?
3 planes: cervical, middle, incisal
What is the Moh of aluminum oxide on discs?
9 Moh
How do you use the disc to establish proximal contouring?
90 degree angles
What are discs coated with
aluminum oxide
______ can create developmental grooves and open embrasures at 90 degrees
aluminum oxide discs
studies have rated that _______ produce highest gloss
astropols
What is 2. contour?
establish outline and functional form smooth CSM
You want to use wheels, felts, and brushes with _____ pressure and ____ RPM
firm pressure, high RPM
______ is the cause of ______ (effect)
friction is the cause of wear
astropol F =
gray (contour)
astropol P =
green (fine finishing) removal of scratches and defects DOES NOT ALTER SHAPE
What is finishing?
gross reduction to obtain anatomical contour
