It is a tooth colored restorative material that is composed of
organic resin matrix and inorganic filler particles dispersed in
it
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1\ORGANIC RESIN MATRIX: a thick liquids made up of two or more
organic molecules that form a matrix around filler particles Most
commonly : bis-GMA (bisphenol A glycidyl methacrylate)
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2\ INORGANIC FILLER PARTICLES: Fine particles of quartz, silica
or glass dispersed in the matrix. Importance of fillers: 1\they
give strength and wear resistance to the material 2\Reduce
polymerization shrinkage
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ACCORDING TO FILLER SIZE COMPOSITES CLASSIFIED INTO: 1\macro
filled(large particles) 2\micro filled(small particles) 3\hybrid
(combination of the two)
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3\COUPLING AGENT: (Silane coupling agent) A chemical that
adheres the inorganic fillers to the matrix to provide stronger
bond.
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The process of composite setting reaction is a polymerization
reaction. ACTIVATION OF POLYMERIZATION: 1\chemical activation
(self-cured) 2\light activation (light-cured) 3\combination
(dual-cured)
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Chemical cured composite resins Two paste systems(base +
catalyst) Disadvantage: the operator has limited working
time(usually it takes 2 minutes before the material becomes stiff
to manipulate)
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One paste Activated by visible blue light source Advantages:
1\requires no mixing 2\the operator can control the working
time
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Two paste system Light and chemical activation Advantage: After
light curing the chemical setting reaction continues in areas not
reached by the light
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1\MACROFILLED COMPOSITE: The first generation
composite(conventional composite) Large particle size Disadvantage:
1\difficult to polish 2\become rough as filler particles are lost
from surface this causes the restoration to be more susceptible to
discoloration
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2\MICROFILLED COMPOSITE: Smaller filler particles When polished
they produce very smooth shiny surface. Disadvantage: Poor physical
properties(weaker,less wear resistant,greater polymerization
shrinkage)compared to other types.
Slide 14
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3\HYBRID COMPOSITE They contain both macro fillers and
micro-fillers Advantages: Strong material that can be polished to a
high shine
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4\ flowable composites These composites flow readily and can be
delivered directly into the cavity by small needle. Uses:
1\preventive resin restoration(in small preparations) 2\pit and
fissure sealants
Slide 17
High viscous resins that contain a high volume of filler
particles, which gives them a stiff consistency They are stronger
and more wear resistant
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1\restoration of posterior and anterior teeth 2\pit and fissure
sealant 3\cementation of fixed prosthodontics
Slide 19
1\Large proximal lesions. 2\When the patient has an allergy to
the material. 3\Restorations of root caries.( better to use glass
ionomer cements)
