Dr.HINA ADNAN

 It is a tooth colored restorative material that is composed of organic resin matrix and inorganic filler particles dispersed in it

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)

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

ACCORDING TO FILLER SIZE COMPOSITES CLASSIFIED INTO:  1\macro filled(large particles)  2\micro filled(small particles)  3\hybrid (combination of the two)

3\COUPLING AGENT:  (Silane coupling agent)  A chemical that adheres the inorganic fillers to the matrix to provide stronger bond.

 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)

 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)

 One paste  Activated by visible blue light source  Advantages: 1\requires no mixing 2\the operator can control the working time

 Two paste system  Light and chemical activation  Advantage:  After light curing the chemical setting reaction continues in areas not reached by the light

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

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.

3\HYBRID COMPOSITE They contain both macro fillers and micro-fillers  Advantages: Strong material that can be polished to a high shine

 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

 High viscous resins that contain a high volume of filler particles, which gives them a stiff consistency  They are stronger and more wear resistant

 1\restoration of posterior and anterior teeth  2\pit and fissure sealant  3\cementation of fixed prosthodontics

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)

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