Dental Composites

This presentation provides an in-depth analysis of the application and biomechanical properties of dental composites, critically examining their role in restorative dentistry. Explore the molecular structure, mechanical characteristics, and clinical performance metrics that make composites the material of choice for a variety of dental applications. Through case studies and recent research findings, the presentation aims to elucidate the material science innovations driving advancements in this field. Recommended for dental practitioners, postgraduate students, and researchers focusing on dental materials and technologies

1. Resin Based Cements Dental Composites

2. Contents Introduction History Definitions Composition & Function Applications Classification Properties Indications / Contraindications Advantages / Disadvantages Finishing & Polishing Repair of composites Restorative Techniques Curing Innovations in Dental Composites Conclusion References

3. Introduction The search for an ideal esthetic material for restoring teeth has resulted in significant improvements in both esthetic materials and techniques for using them. Composite resins have made it possible to provide patients with highly conservative and esthetic restorations Coupled with acid etching and bonding to tooth structure, composite resin presently enjoy universal application.

4. History 1870’s – Dental Silicates 1940’s - Polymethylmethacrylate 1950’s – Dental Silicates + PMMA (Added Strength) (Unfilled Acrylic Resins) The MMA matrices were later replaced with Bis-GMA (difunctional monomer)

5. History 1962 – Bowen developed a new composite His main innovation was : Bisphenol-A glycidyl di-methacrylate as a matrix Organic silane compounds as coupling agents used to bind the filler particles to the matrix Riva YR, Rahman SF. Dental composite resin: A review. InAIP Conference Proceedings 2019 Dec 10 (Vol. 2193, No. 1, p. 020011). AIP Publishing LLC. Zhou X, Huang X, Li M, Peng X, Wang S, Zhou X, Cheng L. Development and status of resin composite as dental restorative materials. Journal of Applied Polymer Science. 2019 Nov 20;136(44):48180.

6. History Riva YR, Rahman SF. Dental composite resin: A review. InAIP Conference Proceedings 2019 Dec 10 (Vol. 2193, No. 1, p. 020011). AIP Publishing LLC.

7. Definitions What is a Composite ? Solid formed from two or more distinct phases (e.g., filler particles dispersed in a polymer matrix) that have been combined to produce properties superior to or intermediate to those of the individual constituents. What is a Dental Composite ? - Dental resin-based composites are structures composed of three major components: a highly cross-linked polymeric matrix reinforced by a dispersion of glass, mineral, or resin filler particles and/or short fibers bound to the matrix by coupling agents Shenoy A, Nair CK. Phillips' Science of Dental Materials-E-book: A South Asian Edition. Elsevier Health Sciences; 2014 Jun 25.

8. Composition of Dental Composites MATRIX FILLER COUPLING AGENT INHIBITORS ACTIVATOR INITIATOR SYSTEM OPTICAL MODIFIERS MAJOR COMPONENTS MINOR COMPONENTS

9. Resin Matrix Bis – GMA 800,000 centipoise UDMA 800,000 centipoise Aromatic / Aliphatic Dimethacrylate Monomers Highly cross-linked, strong, rigid and durable polymer structures TEGDMA 5-30 centipoise Continuous phase 75% Bis-GMA + 25% TEGDMA = 4300 centipoise 50% Bis-GMA + 50% TEGDMA = 200 centipoise Greater the diluent property of monomer, greater is the polymerization shrinkage Developments include oxybismethacrylates , highly branched methacrylates , silsesquioxane , and cyclic siloxane monomers

10. Fillers Crystalline Quartz Lithium Glass Ceramics Calcium Silicates Glass Beads Glass Fibers Beta- eucryptite Calcium Fluoride Barium / Strontium Glass Lanthanum Glass PPF’s Conventionally Used Fillers Other Fillers Must be in high concentration to avoid deformation of matrix Employed to strengthen and reinforce the composite Reduces polymerization shrinkage and thermal expansion Refractive index of the filler must closely match that of the resin for translucency of the composite Skinner's Science of Dental Materials: 1982. 8th Edition Filler size is considered while restoring cavities in the anterior and posterior teeth. Decreased water sorption

11. Fillers Classification of Reinforcing Filler Particles by Size Range Quartz fillers - hard to polish & abrade opposing teeth Filler particles of size range 0.06nm – 0.1nm are produced from pyrolytic process (burning) Nanoparticles enables higher filler loading ( upto 79.5%) Nanoparticles - monodispersed / nonaggregated / nonagglomerated silica nanoparticles (20-25nm) Nanoclusters wear by breaking off individual primary particles rather than plucking out the larger nanocluster particle.

12. Coupling Agent Filler particles - hydrophilic whereas Resin matrix - hydrophobic Organic Silicone compounds – Silane - is used to bond the two together. Most common coupling agent used - g- methacryloxypropyl trimethoxysilane Stress producing during bonding is transferred from one filler particle to adjacent filler particles . Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013 p280

13. Activator - Initiator System Chemically Cured Light Cured 2 Paste System – Catalyst & Universal Paste Universal Paste – Benzoyl Peroxide Initiator Catalyst Paste – Tertiary Amine Activator Mixing both forms free radicals initiating polymerization Uses ultraviolet light to initiate polymerization (470 nm) Photosensitizer used is Camphoroquinone (CQ) Light cured composites contains CQ (0.2 wt %) & an Amine activator CQ adds a yellow tint to uncured composite which neutralizes during curing. Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013 p280

14. Initiator System Camphoroquione (CQ) + Tertiary Amine used Photoinitiator system starts a free radical polymerization (FRP) process CQ absorbs light between 400 – 500 nm range (peak – 470nm) Type 1 photoinitiator molecules – absorbs at lower wavelength (400nm) CQ – yellowish tinge, not preferred in enamel shades Type 1 (phosphene oxide) - anterior composites Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

15. Inhibitors Added in small amounts to prevent spontaneous polymerization of monomers Strong reactivity potential with free radicals formed when composite is exposed to light briefly Inhibitor used is – Butylated Hydroxytoluene (0.01%) Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013 p280 Powdered BHT

16. Color Modifiers Metal Oxides added to composites to impart visual coloration and translucency. Common color modifiers – Titanium Dioxide and Aluminum Oxide (0.001 -0.007 wt %) Darker shades of composite transmit less light than light shades Darker shades – thin layer placement or cured for a long time Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013 p280

17. Polymerization Additional Condensation NO by-products formed Water & Alcohol as by-products Chemically cured composites – Additional Polymerization BASED ON POLYMER STRUCTURE & COMPOSITION Synthesized from polyfunctional monomers Polymers constituted by repeating units linked by functional units of esters, amides, urethane & sulfides Synthesized without the loss of small molecules with the same chemical composition as monomers Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018 Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

18. BASED ON POLYMER CHAIN CONFIGURATION LINEAR BRANCHED CROSS LINKED Monomers linked together in one continuous chain Thermoplastic polymers Can be shaped by heat / dissolved by solvents Examples : Polyethylene / Nylon Side branches of linked monomer molecules protruding from central branch Decreased crystallinity Polymer molecules linked to each other by covalent bonds at points other than their ends. Light cross linking – High Elasticity Tight cross linking – High Rigidity Cannot be shaped by heat or dissolved by solvents

19. Advantages Esthetics Conservative Cavity Preparation Reparability Low Coefficient of Thermal Conductivity Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

20. Polymerization Shrinkage Stress Disadvantages Technique Sensitive Proper Contact & Contour Isolation Secondary Caries Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

21. Classification Nano-Filled Composites Heterogenous Micro-Filled Homogenous Micro-Filled Flowable Hybrid Packable Hybrid Nanohybrid Hybrid (Large Particle) Conventional Hybrid (Mid-Filled) Hybrid (Mini-Filled) Based on Filler Size

22. Classification Based on Manipulation Characteristics Flowable Composites Packable Composites

23. Conventional Composites (Lutz & Phillip, 1983) 75 – 80 % inorganic filler by weight Extreme hardness of the filler particles Rough Surface Texture Poor Marginal Integrity No Radio-Opacity Color Instability due to high water sorption Lutz F, Phillips RW. A classification and evaluation of composite resin systems. J Prosthet Dent, 1983;50: 480-8.

24. Micro-filled Composite (Lutz & Phillip, 1983) Colloidal Silica particles used instead of ground Quartz Particles have small size but large surface area Pyrolytic process - particle agglomeration - long chains – viscosity increases Used in low-stress and subgingival areas (Class III / IV) Weak bond between composite and resin matrix – Chipping Wear Diamond burs used instead of tungsten carbide burs Lutz F, Phillips RW. A classification and evaluation of composite resin systems. J Prosthet Dent, 1983;50: 480-8.

25. Hybrid Composites (Lutz & Phillip, 1983) Mixed fillers – Microfine & Fine Used in High stress sites Fillers – Colloidal Silica + Ground Glass particles containing heavy metals 75% glass particles / 10-20% colloidal silica Lutz F, Phillips RW. A classification and evaluation of composite resin systems. J Prosthet Dent, 1983;50: 480-8.

26. Nanofilled Composites (Lutz & Phillip, 1983) Filler particle size – 1 – 100 nm Particles coated with γ - methacryloxypropyltrimethoxysilane Limits particle agglomeration / doesn’t effect viscosity Superior optical properties and polishability Some nanoparticles exist as loosely bound clusters Above 100 nm, particles reduce translucency and depth of cure Clusters not bonded to each other, reducing the mechanical properties Lutz F, Phillips RW. A classification and evaluation of composite resin systems. J Prosthet Dent, 1983;50: 480-8.

27. Flowable Composites Modification of micro-filled and hybrid composites Reduced filler loading = Lower Viscosity High Anatomical Adaptability Low wear & fracture resistance Used in Class II and Class I restorations

28. Packable Composites Thixotropy for placement and sculpting Greater Depth of Cure Lower polymerization shrinkage / Radiopacity and Wear rate Better Marginal Adaptation High flexural strength / modulus of elasticity / coefficient of thermal expansion Used in Class II restorations Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

29. Applications

30. Properties Properties for polymer-based restorative materials are based on ISO 4049 (ANSI/ADA specification no. 27) PHYSICAL CHEMICALLY ACTIVATED COMPOSITES Working Time – 90 seconds (ADA sp. no. 27) Setting Time – 3 to 5 mins LIGHT CURED COMPOSITES Polymerization starts when exposed to light Curing reaction continues even after 24 hours Studies report 25% carbon double bonds remain unreacted Degree of conversion is said to be 75% About 50% of composite is fully cured in the first 10 minutes. Orange Covers should be placed to avoid pre-polymerization of composite Carbon double bonds converted to single bonds Volumetric shrinkage Higher Filler – Low Shrikage (Hybrid / Fine particle) (1-1.7%) Low Filler – High Shrinkage ( Microfilled ) (2-4%) Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013 Working / Setting Time Polymerization Shrinkage

31. Compensation of polymerization shrinkage Composite related Restoration related Different resin matrices used / filler particle volume Crystal monomers, oxyranes , spiro ortho esters, epoxy polyol system, siloxane-oxirane New systems show 40-50% less shrinkage in vitro Ormocers show reduced polymerization shrinkage Use of flowable composite as lining material to absorb stress Incremental Buildup Using light curing methods that slow down the reaction Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

32. Coefficient of thermal expansion (CTE) Composite expands with change in temperature The CTE of composite should be as close to tooth as possible Generally composites have a higher CTE than that of tooth Filler particles with low CTE are added to composite in order to lower the CTE of the resin. Microfilled composites - higher CTE Controlling CTE is important to prevent marginal leakage between tooth / restoration interface Linear CTE of composites ranges between - 25–38 × 10^−6/°C and 55–68 × 10^−6/°C CTE of enamel - 11.4 × 10^−6/°C CTE of dentin - 8.3 × 10^−6/°C Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018 Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

33. Water Sorption Oral environment is wet Filler particles adsorb water Silane bonds between resin and filler disturbed Diluent monomers + hydroxyl groups in bis-GMA = increased water sorption Water sorption = expansion of material Microfilled composites – High resin content – High water sorption Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

34. Solubility Inorganic filler ions may leech in the surrounding environment This results in breakdown of the restoration Inadequate light intensity and duration Deeper areas of restoration is left with unpolymerized resin matrix High Solubility = Low Wear / Abrasion resistance & color instability Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

35. Radio-Opacity Detection of caries very difficult under radiolucent restorations Glass ceramics with heavy metals used for radio-opacity Ba Sr Zr ADA specification no. 27 requires that composite resins have radiopacity equivalent to 1 mm of aluminum, equal to that of dentin

36. Strength MECHANICAL PROPERTIES Compressive strength of composites – 200 MPa to 300 MPa Compressive strength of Nanocomposites – 450 MPa Lower Filler Volume = Lower Strength Flowable / Microfilled < Hybrid / Packable Stress -> Coupling agent -> Weak Matrix -> Filler particles Use of Cross Linked Polymer Matrix prevents crack formation Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

37. Wear Resistance Composites have low wear resistance Matrix is soft and gets worn off faster leaving the fillers exposed Wear resistance of composites is dependent on various factors : Fillers Porosity Tooth Position Finishing & Polishing Directly proportional > filler volume Indirectly proportional > particle size Softer filler particles > less stress > matrix Air entrapment during mixing or placement of composite Stress buildup within the matrix Posterior teeth More Wear Carbides / Diamonds – Micro Crack formation in resin Unfilled low viscosity resin over the polished composite reduces wear by 50%

38. Biocompatibility Chemical Toxicity Marginal Leakage Inadequately cured composite – Leeching – Long term Pulpal Inflammation Adequately cured composite – Less leeching – No Pulpal Inflammation Rarely – patients and dentists develop allergic reactions to composite Polymerization Shrinkage Marginal Leakage Bacterial Growth Secondary Caries Pulpal Reaction

39. Bisphenol – A – Toxicity Bisphenol – A is a xenoestrogen BPA and other endocrine-disrupting chemicals (EDCs) reproductive anomalies / Anti-androgenic activities Testicular cancer, Decreased Sperm Count, and Hypospadias seen as a result of EDC’s Effect of BPA and other EDC’s humans yet to be ascertained

40. Finishing & Polishing of composites Adapting the restorative material to the tooth Removing the overhangs shaping occlusal surface Surface Roughness Bacterial Growth Secondary Caries Surface Staining Gingival Inflammation Finishing Polishing Removing Surface Irregularities

41. Factors involved in Finishing & Polishing Environment Delayed / Immediate Finish Types of materials Surface coating and sealing Dry or Wet field ? Dry > Wet Marginal Leakage Structural / Chemical Changes Water Cooling Immediate > Delayed Delay – Increased Marginal Leakage Finishing & Polishing should be done shortly after placement Finishing – 15 mins after curing Scalpel blade - Flash Aluminum Oxide Discs in proximal areas Tungsten Carbide / Diamond Burs for blending Fine / Extra Fine polishing pastes Silicone carbide impregnated polishing brushes Microcracks formed Surface polymerized layer removed Immediate > Delayed Surface sealer / Low viscosity resin with no filler Better marginal seal / Microcracks filled

42. Repair of composites The beauty of composites is such that they can be repaired easily. Considerations are made for old or new restorations : Old Restoration New Restoration As the restoration ages – fewer remaining unreacted methacrylate groups remain Oxygen inhibited layer on the resin on the surface Freshly polished restoration still has 50% unreacted methacrylate groups Composite can still be added after finishing and polishing Greater cross linking makes it difficult for the fresh monomer to penetrate the matrix Polished composite has filler particles free from silane Silane bonding agents applied before repair in old restorations Strength of repaired composite is less than half the strength of the original material

43. Acid Etching Used to enhance the formation of resin bond to teeth 30-50% phosphoric acid – enamel rods dissolved to a depth of 10-100um & smear layer removed Differential etching of rods and interprismatic substance creates ‘ enamel pits ’ 4um in diameter Composite flows into the pits and forms ‘ resin tags ’ for anchoring of resin to tooth surface More resin tags produced if unfilled bonding agent applied prior to composite

44. α- Hydroxy Glycolic Acid vs Phosphoric Acid 35% α- Hydroxy Glycolic Acid 35% Phosphoric Acid Originally used in dermatology for skin peeling procedures Less aggressive than Phosphoric acid Etching pattern was same as Phosphoric Acid Rubbing of Glycolic Acid increased the bond strength to enamel elevates collagen synthesis and fibroblast proliferation in, in vivo and in vitro studies Enamel – Etching - 30s / Rinsing with distilled water - 30s Dentin – Etching – 30s / Rinsing with distilled water – 30s / Blot dry Increases surface roughness, wettability, hardness of enamel In dentin, it demineralizes the peritubular and intertubular dentin, exposing type I collagen fibrils Studies have shown that the depth of dentin demineralization does not correlate with bonding effectiveness Enamel – Etching - 30s / Rinsing with distilled water - 30s Dentin – Etching – 30s / Rinsing with distilled water – 30s / Blot dry Cecchin D, Farina AP, Vidal CM, Bedran -Russo AK. A novel enamel and dentin etching protocol using α- hydroxy glycolic acid: Surface property, etching pattern, and bond strength stuDies . Operative dentistry. 2018;43(1):101-10.

45. Degree of conversion (DC) The extent to which monomers react to form polymers or as the ratio of C=C double bonds that are converted into C–C single bonds High degree of polymerization – optimal physical / mechanical properties & biocompatibility Degree of conversion is never complete , reaches a degree of about 50%-75% for conventional composites after curing 50% – 81% for bulk fill composites 24 hour post cure values – 68% - 86% Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

46. C – Factor (Configuration Factor) Tridimensional configuration of a cavity It is the ratio of bonded to unbonded surfaces in a cavity Higher C-factor = More Polymerization Stress Lower C-factor = Lesser Polymerization Stress Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013

47. Factors effecting Degree of Conversion (DC) Intrinsic Factors Extrinsic Factors Resin Composition Filler Composition Photo-initiator System High viscosity of Bis-GMA impairs mobility during polymerization – low DC values Increasing the translucency / Decreasing filler content / Increasing filler size CQ + Tertiary Amines – 1 free radical Mono-acylphosphine oxide – 2 radicals Bis-acylphosphine oxide – 3 radicals Light Curing Units Higher the intensity of light – Higher DC Quartz-tungsten-halogen lights – more heat, less longevity 1 st -2 nd -3 rd Gen LED curing lights – High intensity – Less curing time – Higher DC (Total Energy Concept) High Intensity – High Contraction Stress Fix - variable intensity during curing cycle Pre Heating Pros – decreases viscosity, enhances marginal adaptation, and reduces microleakage Cons – Greater polymerization stress Tauböck et al concluded pre heating bulk fill / conventional – reduce polymerization shrinkage forces – DC remains same Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

48. Curing Lights Handheld devices with a light source and a rigid light guide made of fused optical fibres Upon scission of the initiator molecule ( camphoroquinone ) by visible light in the blue spectrum, in the presence of the aliphatic amine activator, free radicals are produced which initiate the polymerization. irradiance value measured as mW /cm2 Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

49. Types of Light Curing Units QTH Curing Units Plasma Arc Curing Units Argon Laser Curing Units LED Curing Units Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

50. Quartz – Tungsten – Halogen Light Halogen Cycle Filter White Light Wear of bulb 50 Hours till burnout Turn Off Guidelines 30 – 60 secs (2mm thick increment) Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

51. Plasma Arc Curing Lights More Intensity Less Curing Time 2 tungsten electrodes surrounded by xenon gas Expensive Noisy Fan Large Non Battery Operated Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

52. Argon Ion Lasers More Intensity Less Curing Time Laser with photons of same wavelength emitted Expensive Non – Portable Narrow Emission Spectrum Non Battery Operated Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

53. LED Curing Units 2-3 times more intensity Less Curing Time Solid State Light weight Battery Operated Long Life No Filtering Needed 1 st Gen 2 nd Gen 3 rd Gen Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

54. 1 st Generation LED Curing Light Individual LED ‘cans’ Wavelength – 470 nm (max) Low Heat Low Output Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

55. 2 nd Generation LED Curing Lights LED Chips Intense Luminous Output Surpassed QTH & PAC More Heat Production Cooling through Heat Sinks Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

56. 3 rd Generation LED Curing Light CQ imparts yellow which is problematic when producing light / translucent shades Co – initiators added to reduce conc. of CQ Co – initiators get activated at shorter wavelengths Additional LED emitters added Each LED pad emits different wavelength Polywave ® Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

57. Modes of Curing Various methods to minimize or compensate polymerization shrinkage have been the target of clinicians One such approach is to slow the rate of curing, instead of continuous high intensity curing, to allow the flow of composite from the uncured, nonstress areas to the cured, stressed areas. Soft Start Pulse Delay Ramped Cure Pre-polymerization using low intensity followed by final exposure at high intensity of photoactivation. Short durations of light energy applied with no curing (pulsed) in between. A combination of both the pulse delay and soft start polymerization results in ramped curing. Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

58. Blue Light Hazard Acute – Immediate & irreversible retinal burning Highest at 440 nm Chronic – accelerated retinal ageing / Age related macular degeneration Children, persons who have had cataract surgery, or those who are taking photosensitizing medications have a greater susceptibi l ity for retinal damage. Blue Light Blockers for Operators and Patients Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018

59. Restorative Techniques When placing posterior composites, the use of small increments is recommended by many authors for insertion and polymerization so that the after effect of shrinkage stress can be reduced. Horizontal Layering Technique Oblique Layering Technique Vertical Layering Technique Incremental techniques in direct composite restoration . Veeramachaneni et al. J Conserv Dent.  2017 Nov-De (2016)

60. Horizontal Layering Technique Technique used in posterior teeth 3-4 layers of resin placed horizontally Each layer is 2 mm thick This technique tends to increase the C – Factor Increases shrinkage stresses between cavity walls Horizontal Layering Technique Incremental techniques in direct composite restoration . Veeramachaneni et al. J Conserv Dent.  2017 Nov-De (2016)

61. Oblique Layering Technique Placing series of wedge shaped increments Each increment photocured twice - first through the cavity walls - then through the occlusal surface Technique reduces C – factor Prevents distortion of cavity walls Oblique Layering Technique Incremental techniques in direct composite restoration . Veeramachaneni et al. J Conserv Dent.  2017 Nov-De (2016)

62. Vertical Layering Technique Vertical increments placed starting from one wall Photocuring done from behind the cavity wall Reduces gap at gingival wall due to polymerization shrinkage Reduces post operative sensitivity and secondary caries Vertical Layering Technique Incremental techniques in direct composite restoration . Veeramachaneni et al. J Conserv Dent.  2017 Nov-De (2016)

63. Successive Cusp Buildup Technique Individual cusps built up till the level of the occlusal table Reduces finishing time by progressive reconstruction of natural morphology Each cuspal increment is photocured before placing another increment Placement of stains in the central groove done after buildup Incremental techniques in direct composite restoration . Veeramachaneni et al. J Conserv Dent.  2017 Nov-De (2016)

64. Credits : Dr. Rizal Rizky Akbar Private Practice Indonesia

65. Credits : Dr. Rizal Rizky Akbar Private Practice Indonesia

66. Credits : Dr. Rizal Rizky Akbar Private Practice Indonesia

67. Credits : Dr. Rizal Rizky Akbar Private Practice Indonesia

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75. Credits : Dr. Rizal Rizky Akbar Private Practice Indonesia

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79. Innovations In Dental Composites ORMOCERS Organically modified ceramics Molecule sized hybrid structures Inorganic co-polymers Organic co-polymers High Molecular Weight Flexible Relatively Low Viscosity Crosslinking Molecules Abrasion resistance Low polymerization shrinkage Benefits Limited cure shrinkage High Biocompatibility Good Manipulation Excellent Esthetics Rao DB, Chandrappa V. Recent advances in dental composites : An Overview (2019)

80. Fiber Reinforced Composites Glass Fibers / Carbon Fibers / Aramid Fibers Unidirectional / Weave Type / Mesh Type Silane coupling agents used to bond resin matrix and fibers Strength / Stiffness Wear Resistance APPLICATIONS Periodontal Splinting Post Trauma Splint FPD’s Reinforcing / Repairing Dentures Fixed orthodontic retainers Root Posts Increased Fracture Resistance Rao DB, Chandrappa V. Recent advances in dental composites : An Overview (2019)

81. Self Healing / Self Repairing Composites Epoxy based systems contains Resin filled micro-capsules Destroyed when epoxy resin undergoes crazing Releases resin Fills Cracks Reacts with catalyst Polymerizes resin & repairs the crack Rao DB, Chandrappa V. Recent advances in dental composites : An Overview (2019)

82. Smart Composites Based on external stimulus response These composites release : Temperature pH Mechanical Stress Moisture Fluoride Calcium Hydroxyl Ions Into surroundings (when pH is less than 5.5) Caries Protection Rao DB, Chandrappa V. Recent advances in dental composites : An Overview (2019)

83. Bellglass HP Indirect Restorative Material Introduced by Belle de St. Claire in 1996 Increased pressure increases rate of curing and decreases vaporization of monomers Nitrogen gas increases the wear resistance / provides an oxygen free environment increases polymerization rate Increased polymerization Cured under Temperature 138 °C Pressure 29 psi Nitrogen gas Rao DB, Chandrappa V. Recent advances in dental composites : An Overview (2019)

84. Self Adhering Composites Also called “ Compobonds ” Introduced by Kerr Corporation in 2009 Self etching dentin bonding agents + Nano-filled-resins Eliminates Bonding Stage Reduces Post-op. sensitivity Act as shock absorbers Properties similar to Flowable Composites Longer Curing Time Rao DB, Chandrappa V. Recent advances in dental composites : An Overview (2019)

85. Nanocomposites Nanometric Fillers Smooth Finish / texture Less Biodegradation Excellent mechanical properties Anterior / Posterior Use Less Polymerization Shrinkage Less Cuspal Deflections Reduced microfissures in enamel margins Less Marginal Leakage Less Discolouration Reduced Post-Op Sensitivity Rao DB, Chandrappa V. Recent advances in dental composites : An Overview (2019)

86. Antimicrobial Composites Q uaternary A mmonium Polyethyleneimine Silver Zinc Oxide Titania Chitosan Leeching of antimicrobials into surroundings Direct contact elimination of microbes Fatemeh K. et al. (2017) reported use of adhesives incorporated with silver nanoparticles showed greater bond strength Fatemeh K, Mohammad Javad M, Samaneh K. The effect of silver nanoparticles on composite shear bond strength to dentin with different adhesion protocols. J App Oral Sci. 2017;25(4):367-73.

87. Calcium Phosphate Nanoparticles Hydroxyapatite Phosphate Dicalcium Phosphate Anhydrous Tetra Calcium Phosphate Fillers Anhydrous Calcium Phosphate Increases Stress Bearing Capacity Enables Ion Release that inhibits dental caries Xu HH, Moreau JL, Sun L, Chow LC. Nanocomposite containing amorphous calcium phosphate nanoparticles for caries inhibition. Dental Materials. 2011 Aug 1;27(8):762-9 Xie XJ, Xing D, Wang L, Zhou H, Weir MD, Bai YX, Xu HH. Novel rechargeable calcium phosphate nanoparticle containing orthodontic cement. International journal of oral science. 2017;9(1):24

88. Conclusion Patients’ demand for aesthetics, phenomenal developments in resin and filler technologies, advances in nanotechnology, and clinical training in their use has made composite resins a material of choice for direct restorative purposes . The wide range of colors, shades, translucencies, opacities, fluorescence, tones, viscosities, etc., available with the present generation of composite resins has enabled the clinician to provide a restoration that mimics natural tooth structure and optimizes function as well. Further research is always an ongoing process to reduce or eliminate the drawbacks of composite resins.

89. References Shenoy A, Nair CK. Phillips' Science of Dental Materials-E-book: A South Asian Edition. Elsevier Health Sciences; 2014 Jun 25. Dental Composite Materials for Direct Restorations. Vesna Miletic . Springer 2018 Materials Used In Dentistry. S. Mahalaxmi. 1 Ed, 2013 Lutz F, Phillips RW. A classification and evaluation of composite resin systems. J Prosthet Dent, 1983;50: 480-8. Incremental techniques in direct composite restoration . Veeramachaneni et al. J Conserv Dent.  2017 Nov-Dec (2016) Riva YR, Rahman SF. Dental composite resin: A review. InAIP Conference Proceedings 2019 Dec 10 (Vol. 2193, No. 1, p. 020011). AIP Publishing LLC.

90. References Xu HH, Moreau JL, Sun L, Chow LC. Nanocomposite containing amorphous calcium phosphate nanoparticles for caries inhibition. Dental Materials. 2011 Aug 1;27(8):762-9 Xie XJ, Xing D, Wang L, Zhou H, Weir MD, Bai YX, Xu HH. Novel rechargeable calcium phosphate nanoparticle containing orthodontic cement. International journal of oral science. 2017;9(1):24 Fatemeh K, Mohammad Javad M, Samaneh K. The effect of silver nanoparticles on composite shear bond strength to dentin with different adhesion protocols. J App Oral Sci. 2017;25(4):367-73. Cecchin D, Farina AP, Vidal CM, Bedran -Russo AK. A novel enamel and dentin etching protocol using α- hydroxy glycolic acid: Surface property, etching pattern, and bond strength stuDies . Operative dentistry. 2018;43(1):101-10. Rao DB, Chandrappa V. Recent advances in dental composites : An Overview (2019) Zhou X, Huang X, Li M, Peng X, Wang S, Zhou X, Cheng L. Development and status of resin composite as dental restorative materials. Journal of Applied Polymer Science. 2019 Nov 20;136(44):48180.

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