Exam 1 Flashcards
Define intertubular dentin:
Structural component of the hydroxyapatite-embedded collagen matrix
Bulk of the dentin
Define peritubular dentin:
Limited to lining of the tubular walls
Little organic matrix densely packed with apatite crystals
What type of bonds at are the strongest and simplest?
Covalent bonds
What is the relationship between surface energy of a liquid and its ability spread?
A low surface energy of a liquid allows it to readily spread over a high surface energy subtrate
Define wettability:
The measure of the affinity of a liquid for a solid as indicated by the spread of a drop
Define adsorption:
Dissimilar substances in intimate contact with the surfaces of a solid adhere
Define absortion:
The uptake of a liquid by a bulk solid.
The substance absorbed diffuses into the solid material
What is the usage test in a biocompatibility test?
Usage tests are where materials are placed into a situation identical to its intended clinical use
Define microleakage:
Occurs when material may not bond with sufficient strength to resist contraction on polymerization, wear, thermal cycling
What can occur with microleakage?
Gap between tooth and restoration allows influx of materials that may irritate pulp
What is RDT and what is it’s desired value?
Remaining Dentinal Thickness; preferred 0.5 mm minimum
Define stress:
Ratio of force per area (F/A)
Define Tension:
Elongation forces directed away from each other in the same straight line
Define Compression:
Shrinkage forces directed toward each other in the same straight line
Define Shear:
Forces directed parallel to each other not along the same straight line (one portion resists sliding past another)
Define Torsion:
Twisting forces
Define Bending:
Results from a bending movement
Define Strain:
Deformation caused by stress
How do you mathematically define strain?
Deformation = deformation/length
Define proportional limit:
The greatest sustained stress without deviation from the linear proportionality of stress and strain.