Midterm Flashcards
What % of enamel is hydroxyapatite?
90-92%
What are thin faults between enamel rod groups?
Enamel lamellae
Enamel acid solubility: ?pH
Enamel + Fl2 sol: ?pH
Dentin sol: ?pH
Enamel: 5.5
Enamel + Fl2: 4.5
Dentin: 6.5
What kind of dentin is closest to the odontoblast processes?
-Peritubular dentin
What is reparative dentin responsive to?
Moderate irritant
What happens to the peritubular dentin in sclerotic dentin?
it widens and fills with calcified material
What % of dentin is hydroxyapatite?
50% and 1/5 hardness of enamel
What are the 5 objectives of tooth preparation?
RREPR
- Remove defects
- Resist fracture when chewing
- Extend restoration as conservatively as possible
- Provide necessary protection to pulp
- Restore esthetics and function
Where is it acceptable to leave residual caries?
-as affected dentin near the pulp
What do good pulpal and gingival floors and walls do?
- stabilizing seats
- distribute stress
Types of edges/line angles?
- Bevel
- 90 degree
- chamfer
Class 1 Prep surfaces
occlusal
Class 2 Prep surfaces
proximal
Class 3 prep surfaces
proximal of incisors and canines
Class 4 prep surfaces
proximal and incisal of anteriors
Class 5 prep surfaces
cervical 1/3 smooth surfaces
Class 6 prep surfaces
incisal edge or cusp
Where do you NOT want occlusion on a prep?
On the margins (edges of prep)
When do you connect two preps?
When they are less than 0.5 mm apart
How deep should the axial wall depth be on class 2 preps?
0.2-0.8 mm INTO THE DENTIN
In an enameloplasty, what is the maximum amount of enamel that should be removed?
no more than 1/3 of total enamel thickness
Amalgam preps should be at least ______ mm deep
1.5 mm
Gold preps should be at least ______ mm deep
1-2 mm
Porcelain preps should be at least ______ mm deep.
2 mm
What is the purpose of the dovetail?
prevents tipping and proximal displacement
