Test 2 Flashcards
Review self-cure
Self cured (also known as chemically cured) is when two pastes mix and a chemical reaction occurs
Review light-cure
Light cured means it is activated with (blue) light; this is the most common cure for resins
Review dual-cure
Dual cured means it uses both chemical and light, with the light beginning the reaction and chemical reaction occurring where the light can’t reach
Review glass ionomers
Self or light cured fluoride releasing materials. Can be used as luting cements, liners and bases, and restorative materials, and they are very wear resistant. They cannot be polished. They are hand mixed as a powder and liquid and can seal the root surface better than composite resin.
Review resin matrix
Organic resin matrix is a thick liquid made up of two or more types of organic molecules called oligomers. The most commonly used resin for the matrix site is bisphenol-A-glycidyl dimethacrylate (bis-GMA)
Review filler particles
Filler particles are added to organic resins to make them stronger and more wear resistant. Inorganic particles are used such as quartz, silica, and glass. The smaller the particles the smoother the surface will be. The higher the filler content, the stronger and more wear resistant the restoration will be, and it will shrink less when polymerized.
Review coupling agents
The coupling agent saline is used to provide a stronger bond between the inorganic fillers and the resin matrix.
What are the classifications of composite by filler size?
Macrofilled, microfilled, and hybrids, microhybrids, nanohybrids, and nanocomposites
What are macrofilled composites?
Macrofilled composites contain the largest of the filler particles. They have great strength but a dull, rough surface, and they stain easily.
What are microfilled composites?
Microfilled composites contain much smaller particles, making them weaker but they do not stain easily and can be polished to smooth.
What are hybrid composites?
Hybrids are a combination of macro and micro filled
What are microhybrid composites?
A combination of smaller particles and micro fine particles
What are nanohybrid composites?
Nanohybrids are microhybrids with nanosized particles (they are also called universal composites because they are both strong and esthetic).
What are nanocomposites?
Nanocomposites have filler particles that are about a thousand times smaller than conventional fillers.
How are composite resins classified?
Self cured and light cured
What is the purpose of the saline coupling agent
It reacts with the surface of the inorganic filler and of the organic matrix to allow the two to better adhere together, minimizing loss of filler particles and reducing wear.
Review polymerization and shrinkage
The chemical reaction that occurs when low molecular weight molecules called monomers join to form long-chain, high molecular weight molecules called polymers. Chemicals that cause polymerization to occur are initiators and activators. Shrinkage occurs when composite resin is polymerized.
What is the oxygen inhibited layer?
Also called air-inhibited layer, it is a layer of unset resin on the surface of a polymerized bonding resin that is prevented from curing by contact with oxygen in the air. Once composite resin is placed over the bonding resin it will exclude the air and cure when the composite cured, helping facilitate the bond between the two. Oftentimes this layer is wiped off.
What is the optimum levels of fluoride in community drinking water
0.7mg of fluoride per litre
Review desensitizing agents
Used to reduce or eliminate sensitivity. They can be occluded (plugged) into open tubules to stop pressure on nerve endings, or they can desensitize the nerve endings with potassium nitrate.
What is fluorosis and how does it occur?
It is caused by too much fluoride, resulting in an enamel condition.
Review possible causes of tooth sensitivity.
Exposed dental tubules in the oral cavity resulting in pain when fluid in the tubules move (known as hydrodynamic theory), temperature (cold), sugar, acid, exposed root structure.
Review indications for sealants.
Steep cuspal inclines, deep sticky fissures.
Review the steps of sealant placement. (i.e: tooth prep, etch, sealant etc.) What should an etched surface look like? What type of etch is used?
Clean surface with pumice
Etch enamel with 37% phosphoric acid (should be rough)
Rinse with water
Dry the enamel
Bonding (optional)
Place sealant
Cure
Wipe cured surface with gauze or a cotton roll