Quiz 5 Flashcards
o Tooth-colored restorative material
o Used in both anterior and posterior areas of mouth
o Placed directly and indirectly
o Less fracture toughness than metallic restorations
Composite resin
What are the five components to composite resin?
Organic resin matrix
Inorganic filler particle
Silane coupling agent
Initiators/Accelerators
Pigments
What is organic resin matrix made of?
Bis-GMA
UDMA
- Make composite stronger
- Make composite more wear resistant
- Reduce amount of shrinkage occurs when composite is set
Inorganic filler particles
Makes sure composite sets
Initiators/Accelerators
Match color to tooth structure
Pigments
Chemical reaction of small monomers forming long chain polymers
Polymerization
activating initiator by chemical, heat, light, or dual cure
Activation
free radical formed to react with monomers to start growing chain
Initiation
heat from chemical reaction
Exothermic
How long does it take for chemical cure base + catalyst to harden?
About 2 minutes
How long does it take light cure curing light to harden?
Unlimited worked time
shrinkage occurring when composite has been cured
Polymerization shrinkage
How is polymerization shrinkage reduced?
more filler in composite & incremental placement
How is coefficient of thermal expansion reduced?
More filler in composite
How is strength & abrasion resistance reduced?
More filler in composite
What can fillers be made of?
Engineering glass
Quartz
Silica
Ceramic
What determines surface smoothness?
Filler size
What size particles make a smoother surface?
Smaller particles
What determines viscosity and handling?
Amount & size/shape of filler
What equals decreased resin content?
Icreased filler
What are the classifications of composites by filler size?
Macrofilled
Microfilled
Hybrid
Nanofilled composites
First developed
Larger particles
Generally stronger than composites with smaller particles
Macrofilled composites
Why do we no longer utilize macrofilled composites?
- Difficult to polish
- Become rough when polished
- High staining potential
Developed to overcome problems with macrofilled composites
Smaller particles
Smoother polish & glass than macrofilled composites
Weaker, greater shrinkage
Microfilled composites
What has the best esthetics of all composites?
Microfilled composites
What sites can microfilled composites be used on?
Class III, IV, V
Large & small particles
Combine strength and esthetic appeal of macro and micro
Strong, polishes well, wear resistant
Suitable for anterior and posterior sites
Hybrid composites
What sites can hybrid composites be used on?
Class I-V
What composites should be used on patients with a low caries risk?
Hybrid composites
Smallest particle
Best polish
Low shrinkage
High strength
High wear resistance
Nanofilled composites
What sites can nanofilled composites be used on?
All class sites
Class?
-Pits and fissures of posterior teeth, lingual of maxillary incisors
Class I
Class?
-Proximal surfaces of posterior teeth
Class II
Class?
-Proximal surfaces of anterior teeth
Class III
Class?
-Proximal surfaces of anterior teeth and the incisal edge
Class IV
Class?
-Cervical third of anterior and posterior teeth
Class V
Class?
-Incisal edges of anterior teeth, cusp tips of posterior teeth
Class VI
Low viscosity, flows well into prep
* Adapt well to cavity walls and surface irregularities
Well-suited for conservative dentistry
Flowable composite
What are the uses of flowable composites?
- Liners in large cavity prep
- Cervical lesions
- Class I, small, low stress bearing restorations
Aka condensable composite
High viscous & stiff – high filler content
Stronger and more wear resistant than most hybrids
Marketed as substitutes for amalgam
Less likely to stick to instruments used to place
Packable composite
What sites can packable composite be used on?
Class I, II, IV sites
How can composites be detected?
-Softer than enamel
-Radiographs
What is added to composites to be identified on radiographs?
Barium
Strontium
What are the two types of glass ionomer cements?
Conventional glass ionomers
Resin-modified glass ionomers
o Polyacrylic acid + fluoroaluminosilicate glass powder
o Fluoride releasing
o Bond to tooth structure without a bonding agent
o Least esthetic
o Very radiopaque
Glass ionomer cements
What are the 3 ways glass ionomer cements can be used?
Luting cement
Restorative materials
Liners & bases
Release fluoride, low film thickness, good for pulp, bond to tooth structure, crown seated easily
Luting cement
Weak tensile strength, release fluoride, non-carious class V or root caries, no stress-bearing sites
Restorative materials
Thermal protection, protection against chemicals during restoration
Liners & bases
o Blend of resin + glass ionomer
o Created to improve on properties of glass ionomers
Resin-modified glass ionomers
What are resin-modified glass ionomers used for?
Cervical lesions
Low stress-bearing
Class III and V sites
Pediatric restorations in primary teeth
o Similar to composite, modified with polyacid
o Composite systems that release fluoride
o Bonds & sets like dentinal bonding
o Used in low stress bearing class III and V sites
Compomers
