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79 Cards in this Set
- Front
- Back
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Name three reasons for studying dental materials
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understand the behavior of materials
handle them properly access and treat patient (can also educate the patient) |
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Name five oral tissues
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Enamel, Dentin, Pulp, Perodontium, Gingiva
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Name five restrictions on dental materials because of the nature of the oral environment
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biting, corrosion, caries, temperature, biocompatibility, and aesthetics
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Name five dental materials used before 1700
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gold, ivory, wax & gypsum, porcelain, zinc oxide
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Name two products developed in the 1800s
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amalgam, porcelain (for inlays and crowns)
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Name three products developed in the 20th Century
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composites, cast metals (gold), polymers
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Name three organizations that create standards for dental materials
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ADA, FDA, ISO
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Name five types of restorations
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filling, crown, bridge, denture, implant
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Name five types of materials used in dentistry
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impression, cement, temporary, preventative, polishing
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Name two types of classification by location of fabrication
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direct (in dental office) indirect (fabricated in lab)
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Name five classifications of dental caries and restorations by location
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I (Occlusal)
II (Interproximal) III (Interproximal Anterior) IV (Incisal Broken Edge) V (Gingival) VI (Cusp Tip) |
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Name three phases of atomic bonding
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solid, liquid, gas
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Name three types of primary bonds
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ionic (+,-)
covalent (shared electron) metallic (cloud) |
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Name three types of secondary bonds
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permanent dipole
fluctuating dipole hydrogen bonds |
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Name five types of dental materials and their atomic bonds
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Metals (metallic)
Ceramic (ionic) Plastic (covalent) Composite (ionic + covalent) Colloids (suspension; not bonded) |
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Pure gold is __ carat
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24
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What are four properties of materials?
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physical, mechanical, chemical, biological
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Density
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mass of a material in a given volume (mass/volume)
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Vapor Pressure
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tendency to become a gas; measure heat and volume
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Heat of fusion and vaporization
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fusion is solids melting
vaporization is liquids boiling/vaporizing |
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Coefficient of Thermal Expansion
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change in volume/change in temperature
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Electrical conductivity
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electricity flowing from metal to metal
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Viscosity
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ability to flow
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Hardness
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resist scratching and indentation
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Abrasion resistance
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wear resistance of restorations to food & opposing teeth
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Solubility
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solid dissolves in liquid
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Water Sorption
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absorb water
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Color
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Hue (color)
Chroma (saturation) Value (shade of gray) |
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Interaction with x-rays (radiopaque, radioluscent)
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radioluscent is dark (decay, ceramics)
radiopaque is white (crown, metals, restorations) |
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Elasticity
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ability to stretch
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Strain
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CHANGE in length
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Stress
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load/area (FORCE)
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Modulous of Elasticity
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graph showing stress vs. strain
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Elastic limit
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point at which permanent deformation begins
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Resilience
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ability to absorb energy and not be deformed
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Toughness
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energy absorbed to failure point
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Fracture toughness
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energy required to break when a crack is already present
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Fatigue
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failure after repeated stress
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Stress Concentration
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stress increases around defects (crack, bubble, scratch)
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Name and define four types of stress
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compression (crush)
tension (pull) shear (slide) torsion (twist) (bending is a combination of two stresses) |
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Name and define two time dependent properties
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creep (slow flow)
stress relaxation (slow decrease in force) |
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What are three advantages of using adhesion bonding in dentistry?
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retention of restoration
reduction of microleakage (post-op sensitivity and reduce percolation) reduction of recurrent caries |
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Who developed the idea of pit & fissured sealants in the 1950s?
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Dr. Michael Buonocore
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Who developed polycarboxylate cements in the 1970s?
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Dennis Smith (London) polyacrylic acid + zinc oxide
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When were composite resins developed?
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1960s
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What is the difference between adhesive failure and cohesive failure?
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adhesive: bond between tooth and bond fails
cohesive: bonding material bonds break |
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What is the most common acid used to etch teeth?
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orthophosphoric acid (37%)
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How many seconds is the 37% orthophosphoic acid used to etch teeth?
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15-30 seconds
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Why do deciduous teeth take longer to etch?
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enamel rods less regularly arranged
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"Smear layer" refers to what?
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debris layer left after cutting dentin
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The "primer" is used as a ___?
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wetting agent
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What are the steps in the "three step" bonding system?
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etch, prime, adhesive
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In the "two step" bonding system the adhesive contains what two things?
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primer, adhesive
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The adhesive mechanism of dentinal bonding is ___?
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micromechanical (as resin tags)
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Glass ionomer cement is composed of what two things?
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polyacrylic acid and glass ionomer
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Why does glass ionomer cement bond to teeth?
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chemically bonded (acid group reacts with the tooth structure)
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What is the functional group in additional polymerization of acrylic resins?
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C=C
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What is a free radical?
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unpaired electron
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What are the three steps in additional polymerization?
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Initiation, Propagation, Termination
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Name four ways addition polymerization can be activated
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heat, light, chemical, dual-cure
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Name three problems with unfilled resins
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shrinkage
thermal expansion strength & abrasion resistance |
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Who added fillers (glass particles) to dental resins to form the first dental composites?
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Dr. Raphael Bowen
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In dental composites what bonds the filler to the polymer?
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silane coupling agent
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What are three components of dental composites?
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matrix (plastic polymer)
filler (glass particles) silane coupling agent |
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Name three types of composites according to size of filler
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microfilled
macrofilled hybrid |
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What is the filler size of macrocomposites?
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10-25 um
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What is the filler size of microfilled composites?
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.03-.5 um
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What is the filler by weight for hybrid composites?
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75 to 80%
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Which type of composite is used for areas needing strength?
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hybrid or macrofilled
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Which type of composite can be polished to become very smooth?
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microfill
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A special use of composite that has low viscosity:
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flowable
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Why are composites placed incrementally?
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light cure depth & decrease shrinkage
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What is the "air inhibition layer"?
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an external layer that DOES NOT cure because of exposure to oxygen
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What is the purpose of pit & fissure sealants?
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reduce or prevent caries
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What type of restoration is a conservative approach to pit & fissure decay?
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preventive resin restoration (PRR)
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What is the luting material of choice for ceramic restorations?
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composite cement
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The material of choice for Class V restorations:
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glass ionomer
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The most popular bas/liner:
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(resin modified glass ionomer) glass ionomer + resin
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A combination of glass ionomer and composite material is called:
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compomer
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