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  1. 1. CONTENTSIntroduction History Definition Indications Contraindications Advantages Disadvantages Classification Composition Types of composites Recent advances • Mode of supply • Curing and curing lamps • Properties • Clinical techniques • Finishing and polishing • Repair of composites • Tunnel restorations • Sandwich technique • Conclusion • References
  2. 2. INTRODUCTION Composite resins are a class of mature and well established restorative materials that have their own indication in anterior and posterior teeth. Dental composites have continued to evolve with the development of smaller particle sizes, better bonding systems, curing refinements and sealing systems. Although composites are now well accepted in general practice, the complex steps involved have hindered their full success.
  3. 3. HISTORICAL DEVELOPMENT  During the first half of the 20th century, silicates were the only tooth coloured esthetic material available for cavity restoration.  Acrylic resins similar to those used for custom impression trays and dentures replaced silicates during the late 1940s and the early 1950s because of their tooth like appearance , insolubility in oral fluids, ease of manipulation and low cost.
  4. 4.  In 1956, Dr. R.L. Bowen developed a polymer based on dimethacrylate chemistry.  This polymer was generally known as Bis-GMA or Bowen resin, was made up from the combination of bisphenol – A and glycidyl methacrylate.
  5. 5.  1956 - Bowen Resin  1960 - Traditional or Macrofilled composites  1970 - Mircofilled and Light initiated composites  1980 - Posterior composites  1990 - Hybrid, Flowable, Packable, Compomers  2000 - Nanofilled composites
  6. 6. DEFINITIONSKINNER’S A highly cross linked polymeric material reinforced by a dispersion of amorphous silica, glass, crystalline or organic resin filler particles and/or short fibers bonded to the matrix by a coupling agent. DCNA A 3 dimensional combination of at least two chemically different materials with a distinct interface separating the components.
  7. 7. STURDEVANT In materials and science word composite refers to a solid formed from two or more distinct phases that have been combined to produce properties superior to or intermediate to those of individual constituents.
  8. 8. INDICATIONS Class I, II, III, IV, V, VI core buildups Sealants and preventive resin restorations Esthetic enhancement procedures Cements Veneering metal crowns/bridges Temporary restorations Periodontal splinting Non carious lesions Enamel hypoplasia Composite inlays Repair of old composite restoration Patients allergic to metals
  9. 9. CONTRAINDICATIONS Isolation Occlusion Subgingival area/root surface Poor oral hygiene High caries index Habits (bruxism) Operator abilities
  10. 10. ADVANTAGESEsthetics Conservation Less complex Used almost universally Strengthening Bonded to tooth structure Repairable No corrosion No health hazard Cheaper then porcelain
  11. 11. DISADVANTAGES Polymerization shrinkage Technique sensitive Higher coeff. Of thermal expansion Difficult, time consuming Increased occlusal wear Low modulus of elasticity Lack of anticariogenic property Staining Costly
  12. 12. CLASSIFICATION SKINNER’S (10th ed) Traditional composites (Macrofilled) 8-12µm Small particle filled composite – 1-5µm Microfilled composite – 0.04 – 0.4 µm Hybrid composite – 0.6 – 1 µm
  13. 13. • ANUSAVICE (-11th ed)
  14. 14. STURDEVANTClassification of composites based on the filler particle size Megafill- in this one or two large glass inserts 0.5 to 2 mm in size are placed into composites at points of occlusal contact. Macrofill- particle size range between 10 to 100 µm in diameter Midifill - particle size range between 1 to 10 µm in diameter, also called traditional or conventional composites. Minifill - particle size range between 0.1 to 1 µm in diameter Microfill - particle size range between 0.01 to 0.1 µm Nanofill - particle size range between 0.005 to 0.01 µm
  15. 15. As per filler size
  16. 16.  According to CRAIG:  TYPE I:  Class 1 – Macrosized particles – 8-25µ  Class 2 – Mini size particles – 1-8µ  Class 3 – Micro size particles – 0.04-0.2µ  Class 4 – Blend of macro and micro – 0.04-10µ  TYPE II  Class 1: Macrosized 10-20µm (organic particles in unreinforced resin matrix).  Class 2: Macrosize unreinforced particles 10- 20µ (organic in reinforced resin matrix 0.04- 0.2µ organic).
  20. 20. Resin matrix
  21. 21. Inorganic Fillers
  22. 22. FILLER SHAPES Large spherical particles Large irregularly shaped particles Blends
  23. 23. Filler particles are most commonly produced by grinding or milling quartz or glasses to produce particles ranging in size from 0.1-100um. Submicron silica particles of colloidal size (0.04um),referred to as microfillers, are obtained by a pyrolytic or precipitation process.In these processes a silicon compound is burned in an O2 and H2 atmosphere to form macromolecule chains of SiO2.
  24. 24. Material Used:
  25. 25. Classification of fillersi): Quartz: It is made by grinding or milling quartz, was used in early is chemically inert. Because of its hardness it was difficult to grind to a finer size & was difficult to polish, causes abrasion of opposing tooth structure. ii) SILICA :obtained by a pyrolytic or precipitation process.Apart from reinforcing the composite ,it also helps in high scattering and light transmission. Forms of silica:Forms of silica: - Pure silica. - Fused silica. - colloidal silica.
  26. 26. iii) GLASSES: Aluminosilicates & Borosilicates.provides radiopacity. Other fillers:  Tricalcium phosphate & Zirconium dioxide.  Recently fluoridefluoride fillers like: Yittrium trifluoride & Yitterbium trifluoride are introduced. - to ensure acceptable esthetics of composite translucency of fillers should be similar to tooth structure.
  27. 27. Coupling agents H2O
  28. 28. Activator-initiator system
  31. 31. INHIBITORS Butylated hydroxytoluene (BHT)-0.01% 4 –Methoxy phenol (PMP) Extends storage life and provides sufficient working time  THESE COMPOUNDS ARE USED IN AMOUNTS OF 0.1 % OR LESS OPTICAL MODIFIERS Pigments-metal oxides Opacifiers-titanium dioxide & aluminum oxide-0.001- 0.007% Darker shade & opacifier-thin layers UV light absorbers
  36. 36. Prepolymerized paricles(organic fillers)+colloidal silica+monomer microfilled composite paste
  38. 38. Nanofilled Composites  These particles are extremely small (0.005- 0.01 µm) and virtually invisible.  Their particle size is below range of wavelength of light and thus they do not absorb or scatter visible light.  Nanofiller offers means of incorporating radiopacifiers that do not interfere with esthetic properties
  39. 39. THANK YOU “The world hates change, yet it is the only thing that has brought progress.” -Charles Kettering
  40. 40. FLOWABLE COMPOSITES Created for special handling properties– Fluid injectibility.  Introduced in 1996, theflowablecompositesare characterized by thepresenceof filler particlesthat haveaparticlesizesimilar to hybrid compositebut thefiller content isreduced which resultsin viscosity  They werelaunched to improvehandling characteristicsof existing composites
  41. 41. PROPERTIES  Filler size 0.6-1 µm  Filler content 30-55 wt%  Compressivestrength 210-300 MPa  Elastic modulus 4-8 GPa  Flexural strength 70-120 MPa  Depth of cure6 mm
  42. 42. PACKABLE COMPOSITES  Based on newly introduced concept called PRIMM(Polymer rigid inorganic matrix material)  System consist of aresin and aceramic component  Filler phaseinstead of being incorporated areground particlespresent asacontinuousnetwork of ceramic fibers  Fibers composed of alumina& silicawhich are superficially fused to each other at specific sitesto generateacontinuousnetwork of small components
  43. 43.  Silanization of thefibrousnetwork isdoneby infiltration with BiSGMA resin  Consistency of PRIMM based compositeissimilar to freshly triturated massof amalgam PROPERTIES  Inorganic filler 65-81 wt %  Compressivestrength 220-300 MPa  Flexural strength 85-100 MPa  Tensilestrength 40-45 MPa  Elastic modulus3-13 GPa  Depth of cure6 mm
  44. 44. Antibacterial Composites  Compositesthat offer antibacterial properties arepromising sinceseveral studieshaveshown that agreater amount of bacteriaand plaqueaccumulateon thesurfaceof resin compositethan on thesurfaceof other restorativematerial / enamel surface.  Imazato et al 1994 incorporated anon-releasing newly synthesized monomer MDPB with anti-bacterial properties into resin composites.
  45. 45.  MDPB ismethacryloxy decyl pyridinium bromide. It was found to beeffectiveagainst variousstreptococci  However, itsactivity against other important species in plaqueformation likeActinomycesstill needsto be investigated  Silver hasalso been added in compositesto makeit antibacterial
  46. 46. NANOCOMPOSITES Inorganic Phase– nanosized – 0.1 to 100 nm. Increased overall filler level. Areunableto scatter or absorb visiblelight. Nanofillers - usually invisible and offer the advantageof optical property improvement -Mitraet al., 2003
  47. 47. ORMOCERS “Organically Modified Ceramics.” Chemically- MethacrylateSubstituted Alkosilanesie., Organic -Inorganic Copolymers. Based on organically modified heteropolysiloxanes. Filler particlesareincorporated into thiscross- linked inorganic and organic network matrix.
  48. 48. PROPERTIES  Compressivestrength: 410 MPa  Filler Content: 77-80%  Polymerization shrinkage: 1.97 Vol. %  Elastic modulus: 13-14 GPa  Polish ability: high gloss  Color stability: no discoloration ISO 4049
  49. 49. COMPOMERSPolyacid modified resins: Mc Lean & Nicho lso n defined it as: “Materials that may contain either or both of the essential components of a glass ionomer cement but at levels insufficient to promote the acid-base curing reaction in thedark.” Compomer monomerscontain acidic functionalacidic functional groupsgroupsthat can participatein an acid/base glass ionomer reaction following polymerization of the resin molecule
  50. 50.  A resin polymerization takesplaceresin polymerization takesplacewith the compomers after thematerial hasset completely. The glass-glass- ionomer reaction(acid/base) may then occurionomer reaction(acid/base) may then occur in thepresence of water. In thepresenceof water from theoral cavity, the acid functional groups, which areattached to themonomer units, and havenow becomepart of thepolymerized material areableto react with thebase(glass) to stimulatetheglass ionomer reaction. FluorideisreleasedFluorideisreleased asaresult of this reaction.
  51. 51.  Pastecontaining Ca, Al, F silicateglassfiller in dimethacrylatemonomerswith acrylic acid like molecules.  Set by polymerization & then delayed acid/basereaction.  Good strength, biocompatible, low solubility.  Havehigher wear than composite, lower F releasethan conventional GIC.
  52. 52. INDICATIONS:INDICATIONS: Sealing and filling of occlusal pitsand fissures. Restoration of deciduousteeth. Minimal cavity preparation or tunnel preparation Asaliner - cariostatic action isrequired. Core-build – up. Repair of defectivemarginsin restorations.  ClassV repairs.  Erosion  Retrogradefiling materials
  53. 53. GIOMERSHybrid of GlassIonomers& composites. Advantagesof both. Resin based & Contain Pre-reacted Glass Ionomer particles. FlourosilicateGlass+ Polyacrlylic acid & resin. Giomers employ the use of (PRG) technology to form a stable phase of GIC in the restoration and are also known as PRG composites
  54. 54.  Giomersarelight polymerized and require bonding system for adherenceto enamel and dentin. Thebonding system currently availableisknown asReactmer bond (Shofu Inc. Kyoto, Japan).  Reactmer bond istheglassionomer based, tricurable, all-in-one, filled adhesivebased on PRG technology and consistsof UDMA, HEMA, PRG filler, fluoroaluminosilicate glass, acetone, water and initiator.
  55. 55. SMART COMPOSITES Ivoclair introduced a material in 1998 named Ariston pHC (pH control).  Releases Fluoride & Ca Hydroxide when the pH in restoration in thematerial islessthan 5.5
  56. 56.  Smart compositeswork based on thenewly developed alkalineglassfiller which will reducesecondary caries formation at themargin of arestoration by inhibiting bacterial growth. Thisresultsin areduced demineralization and abuffering of theacid produced by cariesforming microorganisms
  57. 57. Composition  Thepasteconsistsof mixtureof different typesof dimethacrylate(20.8 wt %),  Inorganic fillers Ba, Al and F silicateglassfiller (1 μm)  Ytterbium triflouride  Silicon dioxide  AlkalineCasilicateglass(1.6 μm) in dimethacrylate monomers.  It isfilled 80% by weight and 60% by volume.
  58. 58. CEROMERS Ceramic Optimised Resins Laboratory processed inlays, onlays. Somemanufacturers– with fiber reinforcement for short span bridges Three-dimensionally loaded fillersin a polymer matrix of which two arefluoride releasing
  59. 59. Material consists of a paste containing
  60. 60. Indications  ClassI and II posterior restorations(stressbearing areas)  ClassIII and IV anterior restorations  ClassV restorationscervical caries, root erosion, abfraction, wedge-shaped defects  Inlays/onlayswith extraoral post-tempering
  61. 61. INDIRECT COMPOSITES Art glass Bell glassHP Clearfil CR inlay Colteneinlay system Cristobal Sculpture Targis Truevitality Visio gem
  62. 62. MODE OF SUPPLY For chemical cure- syringes/tubs For light cure- spills/syringe/compules
  63. 63. CURING CHEMICAL ACTIVATION cold curing or self curing Advantages  Even polymerization-75% Disadvantages  Oxygen inhibition  No control over Working time
  64. 64. LIGHT ACTIVATION UV light Visible light Advantages  Easy to use, single paste  Less porosity  Less sensitive to oxygen  Command polymerization  Colour stability, colors can be optimized  Better mech properties  Setting time –faster cure – Disadvantages • Increments • Time consuming • Poor accessibility • Variable exposure • Sensitive to ambient light • Shrinkage • Ocular damage • Cost
  65. 65. Comparison Chemical Light cure Polymerization is central Peripheral Curing is one phase Is in increments Sets within 45 seconds Sets only after light activation No control over working time Working time under control Shrinkage towards centre of bulk Shrinkage towards light source Air may get incorporated Less chance of air entrapment More wastage of material Less wastage Not properly finished Better finish
  66. 66. DUAL CURING 2 light cure pastes-syringes/tubs Combines chemical and light curing Disadvantages- air inhibition,porosity Use-cementation of bulky ceramic inlays EXTRAORAL CURING Use- a chemical or light cured composite used to produce an inlay on a tooth or die
  67. 67. CURING LAMPS… 1970’s-”Nuva Light” 360-400nm Types of devices 4 sources of light 440-490nm CURING SYSTEMS UV LIGHT VISIBLE LIGHT
  68. 68. r top units Gun type units-features Types of devices…
  69. 69. Quartz-Tungsten-Halogen units CONVENTIONAL HALOGEN CURING LAMPS E.g.: Optilux 500 Advantages Less cost Simple, well known technology Little/no heat
  70. 70. Disadvantages Slow cure time Plug into electricity Large, cumbersome Decreased output Replace lamp  Halogen gas  protects filament by:  oxidation  re-deposits tungsten to filament by:  Halogen Cycle Light guides
  71. 71. Plasma Arc units  Advantages  Curing time-3 sec  Short procedure  Disadvantages  Heat production  High cost  Large, bulky Two tungsten electrodes Pressurized chamber Contains xenon gas High-voltage spark It ionizes xenon gas
  72. 72. Argon laser unitsADVANTAGES Correct wavelength Deeper & faster curing Better mech properties Decreased sensitivity to curing tip distance Less post-op sensitivity & discomfort DISADVANTAGES Increased shrinkage, brittleness Marginal leakage Heat increase on surface Expensive Bulky equipment
  73. 73. LED units  ADVANTAGES  Cordless,light weight  Long lasting  No heat  Moderate curing time  Quiet  DISADVANTAGES  New technology  Slower than PAC  Batteries must be recharged  Higher cost  Low intensity Narrow emission spectrum 440-490 nm peak at 470 nm near absorption max activation of camphoroquinone efficient
  74. 74.  First generation  high cost  low irradiance  < 300 mW/cm2  increase exposure time Second generation Single large surfaced emitting LED chips lower cost higher irradiance > 600 mW/cm2 similar to halogen High heat production Third Generation 1 or more low- powered chips that emit a second frequency
  75. 75. Optical Safety  Do not look directly at light  Protection recommended  glasses  Shields  May impair ability to match tooth shades
  76. 76. Degree of conversion % of C-C double bonds that have been converted to single bonds to form polymeric resin  Strength, wear resistance Avg 50-60%, light cure-44-75% Cross linked , pendant, free groups Factors Light curing: more shrinkage stress  Staining  Sensitivity  Secondary caries
  77. 77. polymerization shrinkage Value: 1- 4% , stress: 17MPa Prevents bonding to dentin- strength required Causes stress to develop  Externally: interface of restoration & tooth  Internally: between filler and resin
  78. 78. Factors affecting stress development Restorative technique Modulus of resin elasticity Polymerization rate Cavity configuration
  79. 79. Cavity configuration [C-FACTOR] BONDED WALLS UNBONDED WALLS C= During curing, shrinkage leaves the bonded surfaces in a state of stress, while the free surfaces relax some of the stresses by contracting inward toward the bulk of the material. Use of incremental/layering technique
  80. 80.  Two walled cavity Three walled cavity C= 2 Bonded 4 Unbonded C-FACTORC-FACTOR 0.50.5 CAVITY CLASSCAVITY CLASS IVIV C= 3Bonded 3Unbonded C-FACTORC-FACTOR 11 CAVITY CLASSCAVITY CLASS IIIIII
  81. 81.  Four walled cavity Five walled cavityFour walled cavity Five walled cavity C=C= C-FACTORC-FACTOR 22 CAVITY CLASSCAVITY CLASS IIII 4Bonded4Bonded 2Unbonded2Unbonded C=C= C-FACTORC-FACTOR 55 CAVITY CLASSCAVITY CLASSII 5Bonded5Bonded 1Unbonded1Unbonded
  82. 82. REDUCTION OF RESIDUAL STRESS Reduction in vol contraction by alteration of chemistry Low shrink monomers Clinical techniques Curing rate control Incremental build-up Resin based composite systems Dentin-enamel adhesive systems Using material which flows Material with low modulus of elasticity Introduction of air bubbles
  83. 83. CHARACTERISTIC PROPERTY Unfilled acrylic Traditional Small particle Hybrid Micro filled Size (µm) - 8-12 0.5-3 0.4-1.0 0.04-0.4 Inorganic filler (vol %) 0 60-70 65-77 60-65 20-59 Inorganic filler (wt %) 0 70-80 80-90 75-80 35-67 Compressive strength (MPa) 70 250-300 350-400 300-350 250-350 Tensile strength (MPa) 24 50-65 75-90 40-50 30 -50 Elastic modulus (GPa) 2.4 8-15 15-20 11-15 3-6 TEC (ppm/ °C) 92.8 25-35 19-26 30-40 50-60 Water sorption (mg/cm2 ) 1.7 0.5-0.7 0.5-0.6 0.5-0.7 1.4-1.7 Curing shrinkage (vol%) 8-10 - 2-3 2-3 3-4 Radio opacity(mmAl) 0.1 2-3 2-3 2-4 0.5-2
  85. 85. CLINICAL TECHNIQUE… Local anesthesia Preparation of operating site Shade selection Isolation Rubber dam Cotton rolls Gingival retraction cord Preoperative wedging INITIAL PROCEDURES
  86. 86. Tooth preparationCONVENTIONAL DESIGN  Conventional Tooth Preparation are those typical for amalgam restoration  walls in butt joint junction (90º) with the restorative material  Indications- i. Preparations located on root surfaces. ii. Moderate to large class I or class II restorations.
  87. 87. MODIFIED Scooped out preparation Modified preparations are indicated for the initial restoration of smaller, cavitated, carious lesions usually surrounded by enamel & for correcting enamel defects.
  88. 88. This design is indicated when only proximal surface is faulty with no lesion present on the occlusal surface. • BOX-ONLY •FACIAL/ LINGUAL SLOT • Design for restoring proximal lesions on posterior teeth.
  89. 89. Shade selectionShade selection  Composite shade is selected by working with a clean, moist tooth prior to placement of a rubber dam.  Shade selection should be done prior to prolonged drying of teeth because dehydrated tooth becomes lighter in shade as result of decrease in translucency.
  90. 90.  Samples from the shade guide should be applied parallel with the tooth whose color is being matched, not in front of it (it will appear lighter), and not behind it (it will appear darker)  Shade selected acc. to manufactures shade guide or VITA shade guide.  Natural light is preferable.  Shade tab is holded near the teeth to be restored & is partially covered with lip or operator thumb.
  91. 91.  To choose accurate color - small amt. of selected color shade material is placed on the tooth, in close proximity to the area to be restored & cured. Isolation of operating field a) Rubber dam b) Cotton rolls with or without retraction cord
  92. 92. RESTORATIVE TECHNIQUERESTORATIVE TECHNIQUE 1.1. Preliminary steps for enamel & dentin bonding:Preliminary steps for enamel & dentin bonding:  Both liquid & gels etchants are available(32 to 37%). Acidetchingisdonefor15-30secs. Followingthisithastobethoroughly rinsedwithawatersprayfor5-15secs. Laterthesurfaceshouldbedriedwith airorcottonpellets.Theetchedenamel
  93. 93. Bonding  Use low viscosity resin which will flow into etched enamel pores & dentinal tubules to form resin tags.  Act as intermediary between tooth and composite.  Thebondingagentisappliedusingamicrobrush.  Themanufacturer'sinstructionsarefollowedregardingtheno.ofcoatstobeappliedandthecuringtime.(usually20secs labiallyandlinguallyeach) 20 - 30 sec. Apply ampleApply ample amounts,amounts, leaveleave undisturbedundisturbed RemoveRemove solvent withsolvent with air-syringeair-syringe
  94. 94.  Itpenetratestheirregularitiesonenamelandbonds micromechanicallybyformationofresintags.  Ondentin,itpenetratesthecollagennetworkandthedentinaltubules. CURING:  Two categories of technique are commonly used in curing polymers:
  95. 95.  The continuous cure refers to a light-cure sequence in which the light is on continuously.  There are four types of continuous curing:  uniform continuous cure, step cure, ramp cure, and high-energy pulse . Continuous curing is conducted with halogen, arc, and laser lamps.  The discontinuous cure is also called soft cure, which commonly uses a pulse delay.  Distance from a tooth to initiate a cure, and then moving it close to the restoration for the duration of appropriate exposure.
  96. 96.  In uniform continuous curing intensity is kept uniform over the time
  97. 97.  In step curing intensity is increased in sudden step over the time.
  98. 98.  Ramp curing is where the intensity continuously increases over the time
  99. 99. In high energy pulse the high intensity is kept for shorter exposure time.
  100. 100. 3. Insertion of composite3. Insertion of composite  Can be inserted with the help of hand instruments or syringe or guns.  Material is inserted in increments in thickness of 1-2mm
  101. 101. Different designs of increment placementDifferent designs of increment placement 1.Three increment design one flat increment at gingival & occlusal wall & two oblique increments both at proximal box occlusal box. 1st increment thinner than 1.00mm. 2. Horizontal layering design small increments placed horizontally one above the other, starting from gingival wall to occlusal wall.
  102. 102. 3. Oblique layering design Each increment is placed obliquely starting from any sides & curing is done from all three sides. 4. U-shaped layering design At base, both gingival & occlusal gingival, U-shaped increment is given
  103. 103. 5. Vertical layering techq. Increments are placed in vertical fashion starting from one wall & carried on to another wall & curing is done from behind the wall. 6. Layering techq. in the proximal box & curing each increment by inserting the fiber-optic microtip into composite.
  105. 105. REPAIR OF COMPOSITES OLDER RESTORATION Etch, primer, adhesive, composite Bond strength- 50% FRESHLY POLYMERIZED If not yet contoured  Directly place composite If contoured and polished  Re-etch, adhesive, composite
  106. 106. TUNNEL RESTORATIONS  Jinks in 1963 introduced this as a conservative approach for CLASS II.  Hunt & Knight modified the technique INDICATIONS  Pt. with high esthetic demand, low caries rate with small proximal caries without involvement of the marginal ridge.
  107. 107. CONTRAINDICATIONS  Large proximal caries involving marginal ridges.  Marginal Ridges under excess occlusal loads.  Difficulty in access Proximal Caries TunnelTunnel Prep.Prep. Round burRound bur GICGIC placedplaced ComposiComposi te overte over GICGIC
  108. 108. ADVANTAGES  Marginal ridge is preserved  Reduced microleakage  Adjucent tooth preserved DISADVANTAGES  Poor visibility & lack of caries removal  Marginal ridge may be undermined  Prep. may extend closer to pulp than desired
  109. 109. SANDWICH TECHNIQUE  Developed by McLean.  Laminate or Bilayed technique.  Large Class III, IV, V & Class I, II. COMPOSITECOMPOSITE GICGIC GIC COMPOSITECOMPOSITE
  110. 110.  In close sandwich the GIC is placed over pulpal floor and axial wall then composite is placed and cured on the GIC  In open sandwich the GIC is placed on the gingival seat and on that composite is cured till the occlusal level
  111. 111. ADVANTAGES  Favourable pulpal response due to biocompatibility of GIC.  Fluoride release minimizes recurrent caries.  Less composite, less polymerisation shrinkage. DISADVANTAGES  Time consuming.  Technique sensitive.  Adhesion of composite with GIC is a worry.
  112. 112. CONCLUSION  Composites have acquired a prominent place among the filling materials employed in direct techniques. Their considerable aesthetic possibilities give rise to a variety of therapeutic indications, which continue to grow as a result of the great versatility of the presentations offered.  Nonetheless, it should not be forgotten that they are highly technique-sensitive, hence the need to control certain aspects: correct indication, good isolation, choice of the right composite for each situation, use of a good procedure for bonding to the dental tissues and proper curing are essential if satisfactory clinical results are to be achieved.
  113. 113. REFERENCES…  Phillips’: Science of dental materials  Sturdevant : Art and science of operative dentistry  Vimal Sikri : Textbook of operative dentistry  Marzouk : Operative dentistry - modern theory and practice  Craig: Dental marterials  Charbeneau : Principles & practice of operative dentistry  Goldstein : Esthetics in dentistry