Week3 Flashcards
What is the objective of restorative dentistry
To replace diseased or lost tooth structure; restore tooth for function and appearance
Dental materials in oral environment must be? (6)
Biocompatible
Durable
Nonreactive in acid or alkaline conditions
Compatible with other materials
Esthetically acceptable
Tolerable to differing temp & forces
Dental materials are classified by their use which includes (3)
Preventive/ therapeutic materials
Restorative materials
Auxiliary materials
What are examples of preventive /therapeutic materials
Pit and fissure sealants
Mouth guards
Fluoride
What is a direct restoration
Placed immediately and directly into the prepared tooth in a pliable state then sets to harden
What is an indirect restoration
Customized tooth replacements, fabricated in the lab
What are examples of auxiliary materials
Impression materials
Gypsum
Dental waxes
Finishing and polishing materials
What is a nickel allergy
Adverse response from breakdown of the materials components (nickel) in oral environment
What is force
Push pull or twist or a combination of these
What is stress
The force (weight) applied at the surface will create stress within the object that tries to resist the weight
What is strain
The amount of change that the force has produced on the object
What is normal Masticatory forces on the occlusal surface of molar teeth
28,000 lbs/square inch on a cusp tip
What are the 3 basic types of forces
Compressive (pushing together)
Tensile (pulls and stretches)
Shearing (slice apart)
Compressive forces deal with which teeth
Posterior teeth
Torsion force is aka
Torque
Describe torsion force (torque)
Twisting force that has tensile and compressive forces
-descriptive of normal Masticatory events
What is flexural stress
Bending stress
Combo of tension and compression
What is more likely to fracture under compressive stresses
Porcelain
Desirable materials should have ___ solubility
Low solubility
What are examples of materials with low solubility
Gold and porcelain
What is galvanism
Phenomenon of electrical current being transmitted between two dissimilar metals
What is the current that may result in stimulation to the pulp
Galvanic shock
What are excellent thermal conductors
Metals
What are poor thermal conductors
Non metals (ceramics, composite resins)
Dental materials in the mouth are subjected to temperature changes which can result in
Thermal expansion
If the thermal expansion of the restoration does not match the expansion of the tooth what may occur
Microleakage
What is percolation
The space between the tooth and the restoration