1. Composites
   1. Composition& reaction
      1. 3phases
         1. resin matrix
            1. dimethacrylate (Bis-GMA) or urethane dimethacrylate (UDMA) oligomers
            2. oligomer= moderate molecular wt organic molecule (2/more)
         2. dispersed inorganic fillers
            1. filler size
            2. average: 0.2 -0.3micron(fine), 0.04micron(microfine), 1-10nano( nanofilled)
            3. microhybrid composites
            4. contains fine & microfine filler particles
            5. 84% filler by wt
            6. microfilled CR
            7. contains microfine fillers with high surface areas
            8. 35-50% by wt
         3. silane coupling agent
            1. provide good bond
            2. btw inorganic fillers & resin matrix
      2. initiators & accelerators
         1. visible light-curing sys
            1. initiate polymerization
            2. exposure time: 20-40sec
            3. light absorbed by diketone
         2. self-curing sys
            1. organic peroxide initiator & amine accelerator
      3. Pigments
         1. for shades
   2. Properties
      1. low polymerization shrinkage
         1. when set, microhybrid shrink less than microfilled/nano filled
            1. because less resin in microhybrid
         2. 2techniques to reduce
            1. insert CR in layers
            2. prepare lab indirect CR inlay
            3. cement with thin layer of low viscosity resin
      2. low water sorption
         1. microfilled: greater potential to discoloration by water-soluble stains
            1. irreversible effect
      3. COTE similar to tooth structure
      4. high # resistance
         1. microhybrid higher compressive strength than microfilled
         2. CR most likely to fail in tension/bending
         3. elastic modulus (stiffness)
            1. influenced by amount of filler
      5. high wear resistance
         1. higher filler content in microhybrid CR, higher abrasive wear
      6. high radiopacity
      7. high bond strength to enamel & dentin
      8. good colour match to tooth
      9. ease of manipulation
      10. ease of finishing & polishing
   3. manipulation
      1. to achieve bond btw CR & tooth
         1. tooth must be etched & primed
2. Composites for special applications
   1. Flowable CR
      1. lower filler content
         1. higher polymerization shrinkage, low wear resistance, low elastic modulus
            1. useful in cervical abfraction
   2. Packable CR
      1. high depth of cure, low polymerization shrinkage, radiopacity, low wear rate(similar to amalgam)
   3. Laboratory CR
      1. use combination of light, heat, pressure & vacuum
         1. increase polymerization & wear resistance
      2. reinforced with fiber
         1. to increase strength
   4. Core buildup CR
      1. adv over amalgam
         1. bond to dentin,can be finished immediately, easy to contour, high rigidity, have good colour under ceramic
   5. Provisional CR
      1. protempt garant
   6. Repair of ceramic/CR
3. Compomers
   1. composite modified with polyacid
      1. used in low-stress bearing areas, in pt with medium caries risk
   2. release fluoride
      1. but F amount & its duration are lower than GIC
   3. setting primarily light-cured polymerization
      1. acid-base reaction can also occur as compomer absorbs water after placement
4. GIC
   1. recommended for pt with high risk caries
   2. aluminosilicate glass(powder), polymer& copolymer of acrylic acid(liquid)
   3. mixing time: 30-40sec, setting time: 4min
      1. apply varnish after finish contouring
         1. trimming& polishing after 24Hours
5. Hybrid ionomers
   1. low stress bearing area, high caries risk pt
   2. DO NOT apply dentin bonding agent before RMGIC
      1. it decrease fluoride release
6. bonding agents
   1. 3 components
      1. etchant
      2. primer
      3. adhesive
      4. many BA contain primer/adhesive with
         1. hydrophilic groups
            1. improve wetting & penetration of treated dentin
         2. hydrophobic grps
            1. polymerize & form bond with composite
   2. Generation
      1. 4th
         1. total etch (etch&rinse) + multi-bottled system
      2. 5th
         1. total etch + single-bottle system
            1. primer & adhesive combined
      3. 6th & 7th
         1. self-etching + acidic primers/adhesives
            1. used without prior etching & rinsing
   3. Bonding to enamel
      1. micromechanical
   4. Bonding to dentin
      1. removal of smear layer (consist of hydroxyapatite,denatured collagen, decalcification of intertubular dentin)
         1. forms hybrid layer
            1. micromechanical
   5. polymerized separately from composite
      1. minimize shrinkage
7. Light-curing units
   1. quartz-tungsten halogen (QTH)
   2. light-emitting diode (LED)
   3. plasma-arc source (PAC)