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composites (basics)
- 1. GOOD MORNING
- 3. CONTENTS... History Definitions Classification Indications Advantages Composition Each type Mode of supply Curing Properties Clinical technique Tooth preparation Acid etching Insertion Conclusion
- 4. HISTORY… 1855-vulcanite/ebonite 1868-John Wesley Hyatt-”celluloid” 1878-Thomas fletcher – Silicate cement 1937-Dr Walter Wright-methyl methacrylate resin (acrylic resins)
- 5. 1955 Michael Buonocore 1962 Dr Rafael Bowen – BisGMA 1970’s Microfilled Composites 1972- Light Curing 1981 Hybrid composites (Bayne, J Dent Educat, May 2005)
- 6. What is a composite? Natural composite? Dental composite? synonyms
- 7. 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.
- 8. DCNA A 3 dimensional combination of at least two chemically different materials with a distinct interface separating the components.
- 9. McCABE A composite material is a product which consists of at least two distinct phases normally formed by blending together components having different structures and properties.
- 10. 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
- 11. Periodontal splinting Non caries lesions Enamel hypoplasia Composite inlays Repair of old composite restoration Patients allergic to metals
- 12. CONTRAINDICATIONS… Isolation Occlusion Subgingival area/root surface Poor oral hygiene High caries index Habits (bruxism) Operator abilities
- 13. ADVANTAGES… Esthetics Conservation Less complex Insulative Used almost universally Strengthening Bonded to tooth structure Retention Microleakage staining Repairable No corrosion
- 14. DISADVANTAGES… Polymerization shrinkage Technique sensitive Higher coeff. Of thermal expansion Difficult, time consuming Increased occlusal wear Low modulus of elasticity Bio-compatibility ?? Staining Costly
- 15. CLASSIFICATION… ADA Specification No. 27 (JADA Vol 94, Jun 1977) Type I Type II REQUIREMENTS • Working time • Hardening time • Opacity • Colour stability • Tensile strength • Water sorption at 37°C
- 16. classification… SKINNER’S (10th ed) Traditional composites (Macrofilled) 8-12m Small particle filled composite – 1-5m Microfilled composite – 0.04 – 0.4 m Hybrid composite – 0.6 – 1 m
- 18. classification… STURDEVANT As per filler size Megafill-β quartz , large size Macrofill – 10-100 m Midfill – 1-10 m Minifill – 0.1-1 m Microfill – 0.01-0.1 m Nanofill – 0.005-0.01 m Hybrids Homogenous/heterogenous Modified composites By weight or volume percent
- 19. As per filler size
- 20. As per weight /vol percent
- 22. Chronology MACROFILLED FINE PARTICLE :Traditional/conventional-8- 10 µm FINE FINISHING:Microfilled-0.02-0.04µm Homogenous heterogenous HYBRIDS-2-5 µm Minihybrids-0.1-1 µm
- 23. classification… MARZOUK-generations 1st -Macro ceramics 2nd -Colloidal silica 3rd -Hybrid :macro and micro colloidal ceramics 4th –Hybrid : heat cured irregularly shaped 5th -Hybrid : heat cured spherical 6th -Hybrid : agglomerates of sintered micro ceramics
- 24. classification… CRAIG TYPE I-polymer materials for occlusal TYPE II-other polymer-based materials Class 1: self cure Class 2:light cure • Group 1 • Group 2 Class 3:dual cure
- 25. classification… FERRACANE Types Filler Size Volume Conventional Quartz Glass Avg: 20 m Range: 1-100 m 50-60% Microfill Fused silica SiO2 Avg: 0.04 m Range: 10-50 m 30-55% Small hybrid Quartz / Glass Avg: 0.5-1.0 m Range: 0.1-3 m 50-65% Midsize hybrid Quartz / Glass Avg: 1.0-3.0 m Range: 0.1-10 m 65-70%
- 26. classification… DCNA (Leinfelder K. Apr 1985) Conventional composite – 15 - 35 m Intermediate composite – 1-5m Microfilled composite – < 0.04m DCNA (Jan 2001) Type I-microfill with fumed silica Type II-others with crushed quartz/glass
- 27. classification… LUTZ & PHILIPS (J. Prosth Dent. Oct 1983) Macrofilled Microfilled Homogeneous Splintered Spherical Agglomerated Hybrid
- 29. classification… WILLEM’S (Dental Materials, Sept 1992) Densified Midway filled • Ultra fine- anterior teeth • Fine Compact filled • Ultra fine- posterior teeth • Fine Homogeneous microfine Heterogeneous microfine Miscellaneous Traditional Fibre-reinforced
- 30. classification… G.J. PEARSON (Dental Update, Sept,1991) Conventional Microfine Hybrid
- 31. classification… Based on inorganic loading Heavy filler material – 75% Lightly filler material – 66% Based on their area of application Anterior Posterior Based on method of curing Chemical Light cure UV Visible staged Heat cure Dual cure
- 32. Based on consistency Light body – flowable Medium body – Homogenous microfills, macrofills and midifills Heavy body – packable Hybrid minifills Based on Matrix Composites based on BisGMA Composites based on UDMA
- 34. OTHER COMPONENTS Activator initiator system Colour stabilizers Inhibitors Optical modifiers Pigments
- 35. Resin matrix… PRINCIPAL MONOMERS BIS-GMA-aromatic-1962-”BOWEN’S RESIN” Modified BIS-GMA UDMA- 1974 (Foster and Walker) DILUENT MONOMERS TEGDMA-aliphatic EGDMA HEMA NEW MONOMERS
- 37. Inorganic fillers… Improves material properties Benefits of fillers: Reinforcement of matrix-strength, hardness wear, polymerization shrinkage-3% thermal expansion, heat evolved viscosity, radiopacity water sorption Contribute to esthetics
- 38. “Filler loading” 52-88% wt 30-70% vol-74% max Filler surface area 50-400 m2/gm
- 39. CLASSIFICATION: Materials used Filler sizes & its distribution shape Filler volume Radiopacity Hardness
- 40. MATERIALS USED: Pure silica Crystalline Non-crystalline Crystobalite Tridymite quartz Glass Modifications by ions: Li, Al Ba, Zn, Y, St, Zr, B Disadvantages Egs
- 42. Amorphous silica Colloidal silica Pyrolytic/precipitation process- Pyrogenic/fumed silica Agglomerated silica-1-25 m
- 43. PYROGENIC SILICA
- 44. Organic fillers Fibre fillers Single crystals-SiC Crystalline polymers
- 45. FILLER SIZES Mega, macro, midi, mini, micro, nano Marzouk: Macro-ceramics Colloidal & micro-ceramics Fabricated macro-reinforcing phases & colloidal micro-ceramic Properties-fluidity -surface roughness- 0.2-0.6 m
- 46. FILLER DISTRIBUTION (Lopes et al, J Esthet & Restor Dent 2004) Hybrids- 0.04-3 m (Avg 1-3 m), -7-15% microfillers Microhybrids – Avg 0.8-1 m - polishable, mech properties, uniform filler load Minifilled Hybrids- Avg 0.4-0.6 m - easy to light cure, polishability CONTINUUM-FILLED MATERIAL-66% synthetic Zr/Si - 0.01-3.5 m (0.6m) Hybrid: ClearFil Microhybrid: TPH Spectrum Minifilled hybrid: Vitalescence
- 47. FILLER SHAPES Large spherical particles Large irregularly shaped particles Blends Refractive index
- 49. Activator-initiator system… CHEMICALLY ACTIVATED Benzoyl peroxide initiator (universal paste) Aromatic tertiary amine activator (N,N, dimethyl-p- toluidine)(catalyst paste) LIGHT ACTIVATED Camphoroquinone -0.2%-1% Organic aliphatic amine –dimetylaminoethyl methacrylate (DMAEMA)-0.15% Blue light
- 50. Inhibitors, optical modifiers… INHIBITORS Butylated hydroxytoluene (BTH)-0.01% Functions OPTICAL MODIFIERS Pigments-metal oxides Opacifiers-titanium & aluminum oxide-0.001-0.007% Darker shade & opacifier-thin layers UV light absorbers
- 51. TYPES OF COMPOSITES… 4 TYPES TRADITIONAL HYBRID MICROFILLED SMALL-PARTICLE
- 52. Traditional composites… 1970s. Amorphous silica & quartz (8-12m)- 60-70% vol. Indications
- 53. ADVANTAGES DISADVANTAGES Compressive, tensile strength Stiffness Hardness Polymerization shrinkage Water sorption, thermal expansion Polishability Surface roughness Staining, plaque Occlusal wear Poor esthetics
- 54. Small particle composites… Filler size 0.5-3 m (65-77 % vol) Glass particle with heavy metals & colloidal silica Indications
- 55. ADVANTAGES DISADVANTAGES Good mech properties Good smoothness Wear resistance Less polymerization shrinkage Radioopacity prone to wear and deterioration.
- 56. Microfilled composites… Colloidal silica – 0.04 m -20-59 % vol Agglomerates Sintering of colloidal silica Prepolymerized composite fillers
- 57. ADVANTAGES DISADVANTAGES Best surface finish Excellent wear resistance Tensile strength Water sorption and CTE fracture resistance Radioluscent Polymerization shrinkage
- 58. Hybrid composites… Fillers 0.4-1m – 60-65 % vol Colloidal silica (10-20 wt%) Glass particles with heavy metals (75-80 wt%) Intermediate properties Indications
- 59. ADVANTAGES DISADVANTAGES Good physical properties Improve wear resistance Superior surface morphology Good esthetics Increased surface roughness with time
- 60. CHARACTERISTIC PROPERTY UNFILLED ACRYLIC TRADITI ONAL SMALL PARTICLE HYBRID MICROFILL ED Size (m) - 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 Knoop hardness (KHN) 15 55 50-60 50-60 25-35 Curing shrinkage (vol%) 8-10 - 2-3 2-3 2-3 Radio opacity(mmAl) 0.1 2-3 2-3 2-4 0.5-2
- 61. TRADITIO NAL SMALL PARTICLE MICROF ILLED HYBRID Mechanical Polymerization shrinkage x Polishability x Wear resistance Esthetics x Use in posteriors x x a
- 62. MODE OF SUPPLY… Basic six systems Chemically cured paste-paste Chemically cured / Photo cured liquid-powder Chemically cured / Photo cured paste – liquid Photo cured one paste system Photo cured one liquid system Chemically cured 3 / 4 part system
- 63. For chemical cure- syringes/tubs For light cure- spills/syringe/compules
- 65. CHEMICAL ACTIVATION Chemistry Advantages Even polymerization-75% Disadvantages Oxygen inhibition Working time
- 66. 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
- 67. Disadvantages Increments Time consuming Poor accessibility Variable exposure Sensitive to ambient light Shrinkage Ocular damage Cost
- 68. 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
- 69. DUAL CURING 2 light cure pastes-syringes/tubs Chemistry Indications Disadvantages EXTRAORAL CURING
- 70. CURING LAMPS… 1970’s-”Nuva Light” Disadvantages Types of devices 4 sources of light CURING SYSTEMS UV LIGHT VISIBLE LIGHT
- 71. Counter top units Gun type units-features Types of devices…
- 72. Counter top units Gun type units Fiber optic handpiece curing attachments Smaller diameter of light guide Less intense light source Periodic need for replacement of fiber optic cords.
- 73. Quartz-Tungsten-Halogen units CONVENTIONAL HALOGEN CURING LAMPS E.g.: Optilux 500 Advantages Less cost Simple, well known technology Little/no heat
- 74. Disadvantages Slow cure time Plug into electricity Large, cumbersome Decreased output Replace lamp Light guides
- 75. ENHANCED/ FAST HALOGEN LIGHTS (Christensen;JADA,Jun 2002) E.g.: Optilux 501-Turbo Tip Advantages Faster cure Proven technology Disadvantages Narrower light guide Generate heat Higher cost
- 76. HIGH-INTENSITY HALOGEN LIGHTS (Christensen;JADA,Apr 2004) E.g.: Swiss Master light Very intense light Water-cooling Advantages Built-in radiometer Disposable curing tips Faster curing Experimental
- 77. Plasma arc units Advantages Curing time-3 sec Short procedure Disadvantages Heat production High cost Replacement costly Large, bulky
- 78. 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
- 79. 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
- 80. Light curing variables Spectral output
- 83. Energy required: -16 J/cm2 for 2mm - 40 sec x 400 mW/cm2 Light attenuation: opacity, filler size, pigment shade, tooth structure -“SOGGY BOTTOM” QTH, PAC, Laser-(> 1000mW/cm2 ) Depth of cure-increases Time of exposure-decreases Increases degree of conversion in deeper areas
- 84. 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
- 85. 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 Inelastic deformation of tooth (Sakaguchi, Dent Mat, 2005)
- 86. Factors affecting stress development Restorative technique Modulus of resin elasticity Polymerization rate Cavity configuration
- 87. Cavity configuration Ratio of bonded to non- bonded surface Use of incremental/layering technique
- 88. 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 Combe & Burke, Dental update2000 Deliperi & Bardwell JADA, Oct 2002
- 90. SOFT START-Mehl et al (1997) 10sec-150 mW/cm2 30-50 sec-700 mW/cm2 150mW/cm2 increase to 1130 mW/cm2 in 10 sec Constant for 10 sec
- 91. HIGH ENERGY PULSE CURING 400 mW/cm2 -10 or 20 sec Delay -10 or 20 sec 400 mW/cm2 -10 or 20 sec PULSE DELAY CURING 3 sec -200 mW/cm2 Delay -3-5 min, finish 30 sec -600 mW/cm2 Advantages of soft start
- 92. Placement techniques (Deliperi & Bardwell, JADA,Oct 2002) PLACEMENT TECHNIQUES INCREMENTAL TECHNIQUES DIRECTED SHRINKAGE TECHNIQUE BULK TECNIQUE Horizontal technique Three-site technique Oblique technique Successive cusp build-up technique Modified successive cusp build-up Split incremental technique
- 93. TRANS-ENAMEL POLYMERIZATION (Belvedere, DCNA, Jan 2001)
- 96. SUCCESSIVE CUSP BUILD-UP TECHNIQUE (Leibenberg, 1996)
- 97. SPLIT INCREMENTAL TECHNIQUE (Hassan & Khier, General dentistry, Nov-Dec 2005)
- 99. PROPERTIES… PROPERTIES PHYSICAL MECHANICAL CLINICAL Working, setting time Polymerization shrinkage Thermal properties Water sorption Solubility Colour stability Wear Depth of cure Radiopacity Biocompatibility Staining Secondary caries Marginal integrity Post-op sensitivity Flexural strength Compressive strength Knoop hardness Bond strength Rigidity Fracture toughness creep
- 100. Physical properties WORKING & SETTING TIME Light cure: surface hardens in 60-90 sec Chemical cure: 3-5 min POLYMERIZATION SHRINKAGE Light cure: 60% in 60 sec Debonding, cusp fracture Macrofilled:1-2.5% Microfilled:2-3.5% Microhybrid:0.6-1.4% Chemical cure: even, towards centre
- 101. THERMAL PROPERTIES Places additional strain on bond-percolation Values for tooth, amalgam, unfilled resins, composites COLOUR STABILITY Stains Change of colour Stress cracks Debonding of filler Oxidation Water sorption WATER SORPTION & SOLUBILITY Macrofilled: 0.-1.1 mg/cm2 Microfilled: 1.5-2 mg/cm2 Solubility: 0.01-0.06 mg/cm2 Benefits Colour instability, leaching, less wear resistance
- 102. Mechanical properties FLEXURAL STRENGTH & MODULUS 50% less for microfilled, flowable composites Thus used in cervical lesions COMPRESSIVE STRENGTH Similar for all (240-290 MPa) Transverse strength-45-125 MPa KNOOP HARDNESS Hybrid: 35-65 KHN Microfilled: 18-30 KHN BOND STRENGTH For enamel, dentin For other substrates
- 103. RIGIDITY Microfilled: 4-8 GPa Hybrid: 8-19 GPa (similar to dentin) Large MOD restorations CREEP Microfilled: creep FRACTURE TOUGHNESS Resistance to crack growth Microfilled: 0.7-1.2 MNm- 1.5 Hybrid: 1.4 – 2 MNm-1.5 Decreases with time
- 104. Clinical properties WEAR Types-CFA, OCA, FCA, PCA, toothbrush, fatigue 4 mechanisms Microfracture theory Hydrolysis Chemical degradation Protection Macro & microprotection Wear of opposing enamel
- 105. DEPTH OF CURE Increasing depth Increased time Heavily filled Microfilled & hybrid Light & translucent shade Efficiency of light Distance of tip Through tooth Conc of photoinitiator “step” the light for large restorations Large tip-more time-60 sec
- 106. RADIOPACITY To detect secondary caries By Ba, Strontium, Zr glasses Should be > enamel
- 107. BIOCOMPATIBILITY Inherent toxicity-BPA (xenoestrogenic), HEMA- allergenic Marginal leakage Activation light Gingival tissue
- 108. MARGINAL INTEGRITY 5 ways to reduce (Cheung, J prosth Dent,1990) Acid etch technique Dentin bonding Cavity design Incremental technique Sealing the margins-unfilled resin Staining, Secondary caries, Post-op sensitivity
- 109. CLINICAL TECHNIQUE… Local anesthesia Preparation of operating site Shade selection Isolation Rubber dam Cotton rolls Gingival retraction cord Preoperative wedging INITIAL PROCEDURES
- 113. Bevels Partial bevel Long bevel Hollow ground bevel Scalloping Skirting Axial bevel tech (Leibenberg, Quint Int, 2000)
- 114. Restorative procedures Pulp protection Acid etching Application of primer, adhesive Matrix placement Inserting the composite Contouring the composite Polishing
- 115. Acid etching… 1955- Michael Buonocore Effects of acid etching Removes interprismatic, tops, sides Increases surface area and energy Irregularities, depressions-25 µm Exposes proteinaceous material Removes deposits, plaque Polar phosphate group added Requirement for etching
- 116. Etching patterns- 4 types Silverstone (1974) Etched zone Qualitative porous zone Quantitative porous zone Macrotags, microtags TYPE I TYPE II MIXED TYPE
- 117. SUBSTANCES USED PHOSPHORIC ACID >50% -monocalcium phosphate monohydrate < 27% dicalcium phosphate monohydrate Citric acid -10% Polyacrylic acid-40% Maleic acid Nitric acid-2.5% With ferric oxalate With aluminium oxalate Pyruvic acid + glycine Hydrochloric acid Lactic acid Monohydroxy carboxylic acid α-ketocarboxylic acid
- 118. Bond strength- 18- 22 MPa Mode of supply Liquid Gel Etching time
- 119. Application of primer, adhesive Matrix placement Palodent Compositight matrix system Tofflemire Polyester strips
- 120. Insertion of the material
- 121. Finishing of the restoration
- 122. 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
- 123. COMMON PROBLEMS… Poor isolation White line or halo around enamel margin Voids Missing proximal contacts Incorrect shade Poor retention Contouring and finishing problem
- 124. LONGIVITY OF COMPOSITES… Roulet, J of Dent, 1997 Amalgam – 0.3-6.9% - 20 yrs Composites-0.5-6.6% - 10yrs Chadwick (2001) Amalgam-94.5 % after 7 yrs Composites-67.4% after 7 yrs
- 125. CONCLUSION
- 126. THANK YOU “The world hates change, yet it is the only thing that has brought progress.” -Charles Kettering