Operative Part 2 Flashcards
What is a GV black class 6 classification?
Just incisal edge of anterior or cusp tip of posterior
What is friable enamel?
Enamel that is hypomineralized. Not only is it weaker, Bonding agent is not as effective in friable enamel.
Ideally, cavosurface margins should be > or = to ___ degrees
90
A cutting bur is likely to have ___ blades while a finishing bur is likely to have ___ blades
6
12
You have to lose about __% of enamel mineral before you can see a radiolucency.
25%
In other words, the actual disease is 25% worse than it appears on an X-ray
Define dental ferrule
A band that encircles the external dimension of tooth structure
What is the minimum ferrule length when restoring a root filled maxillary central incisor with a post and core retained crown?
1.5mm
True or false… ferrule refers to the step-like feature on a tooth for a crown
False.. ferrule refers to the portion of the crown that touches the axial walls of the tooth
What comprises the biological width?
1mm connective tissue attachment
1mm epithelial attachment
1 + 1 = 2mm biological width
It is generally safe to place crown margins __ subgingival without impinging on the biological width
0.5mm (AKA there needs to be 2.5mm from crest of bone to crown margin at minimum)
What are two methods to prepare a tooth for a crown that would otherwise impinge on the biological width?
Crown lengthening (bone down)
Orthodontic extrusion (tooth up)
Name two different types of chemicals used for external bleaching
Hydrogen peroxide
Carbamide peroxide
What are the differences between hydrogen peroxide and carbamide peroxide?
Hydrogen peroxide - breaks down faster (30-60 minutes)
Carbamide peroxide - remains active longer (2-6 hours), increased shelf life
For every 10% of carbamide it forms about ___% of hydrogen peroxide. In other words, its a __:___ ratio
3
1:3
True or false… there is no difference in sensitivity, rebound/regression, and results between hydrogen peroxide and carbamide peroxide
True
What percent of hydrogen peroxide is used for in-office visits only?
30-40%
What are some risks of external bleaching?
Gingival irritation
May worsen tooth sensitivity (reversible)
Will not change the color of fillings and crowns
Will not be effective against intrinsic stains
True or false… class 1 restorations include: lingual of maxillary incisors, occlusal of posteriors, and occlusal 2/3 of F/L of molars
True