Exploring the Factors and Aspects of Composit - OSTEOCOM

Figure 1: Initial case involving Black Class IV cavity of #3 after fracture.IntroductionResin-Based MaterialsThe wide variety of composite materialsavailable today provides many opportunitiesbut can also cause confusion. Usersof these materials should be familiarwith their characteristics and distinctions.1-3According to classifications proposedby Ardu and colleagues, 4 resin-basedmaterials can be divided into conventional,hybrid, and microfilled categories,depending upon the filler size andcharacteristics. Hybrid-defined compositematerials can be further divided intocoarse, fine, and micro classifications,which can be additionally divided intohomogenous and inhomogeneous subclassifications.Additionally, these materialscan be placed into four differentgroups, according to the matrix nature:• methacrylates• ormocers• compomers• silorane-based.MethacrylatesThe most well-known materials are thehybrid composites. This technology,based on methacrylates and differenttypes of filler coupled with silanes, hasbeen continuously improved. Somedisadvantages, such as volumetricshrinkage, bacterial adhesion, and sideeffects due to monomer release, stillremain, but the new technologies offerimproved materials. To reduce thesenegative factors, manufacturers haveworked on materials adapting the individualcomponents. The fillers are madeof quartz, ceramic, silica, and other oxides.When filler content is increased,polymerization shrinkage, water absorption,and the linear expansion coefficientare reduced. Furthermore, compressiveand tensile strength, modulusof elasticity, and wear resistance aregenerally increased. 5Nanohybrid composites are the newestfamily and probably the most widespreadon the market today. They aredesigned to provide superior estheticand wear resistance as well as excellentpolishing and handling. Their agglomeratednanoclusters, interspersed withmicro-sized particles, give them veryacceptable wear characteristics. Consequently,they are considered “universal”materials suitable for anterior and posteriorteeth.These composites can have differenttypes of filler particles: prepolymerized,finely milled agglomerated nanoclusters;larger (submicron-sized) glass orsilica particles in the range of 0.4 m;and individual nano-sized particles(0.05m).This family of materials has manydesirable features regarding clinicalapplication, as will be explained. Examplesof these materials include thefollowing:• Filtek Supreme XTE and Filtek Z250XT (3M ESPE; St. Paul, MN)• IPS Empress Direct and Tetric EvoCeram (Ivoclar Vivadent; Amherst,NY)• Enamel Plus HRi (Micerium;Avegno (GE), Italy)• Miris 2 and Synergy D6 (Coltène/Whaledent; Cuyahoga Falls, OH)• Venus Diamond and Venus Pearl(Heraeus Kulzer; South Bend, IN)• Herculite Ultra and Premise (Kerr;Orange, CA)• G-aenial and Kalore (GC America;Alsip, IL)• RefleXions XLS (Bisco; Schaumburg,IL)• Esthet-X HD (Dentsply Caulk; Milford,DE)• Estelite Sigma Quick (Tokuyama;Tokyo, Japan)• Grandio (Voco America; BriarcliffManor, NY)• Clearfil Majesty (Kuraray; Houston,Tex).OrmocersWith organically modified ceramic materials(ormocers) (e.g., Admira, VocoAmerica), the methacrylate has beenpartially replaced by an inorganic network.According to some studies, thebiocompatibility was not improved inall cases. 6,7CompomersCompomers aim to combine the positiveproperties of glass ionomers withcomposite technology (e.g., Dyract[Dentsply Caulk] and Compoglass [IvoclarVivadent). However, this goal hasonly partially succeeded, because thefluoride release is low. The fluoride releaseof compomers increases quicklyinitially (in the first 24 hours), but decreasesquickly, too. 8-11 Compomers aremost suitable for restorations in the deciduousdentition due to their low abrasionresistance. 12-14108 Winter 2013 • Volume 28 • Number 4

FerrarisAnother important point to consider is the estheticbehaviors of resin-based materials.Siloranes and Low-Shrinkage Resin-Based MaterialsManufacturers have addressed problemsrelated to shrinkage of resin-basedmaterials in different ways, includingincreasing molecular weight and developingmaterials with ring-shaped molecules.For example, silorane (siloxanesand oxirans) replaces the chain monomersin the composite matrix via ringshapedmolecules (e.g., Filtek SiloraneLS). These materials are hydrophobicand need to be bonded to the dentalhard tissue with a specific adhesive system.According to some studies, 15-17 silorane’slow shrinkage leads to a lowercontraction stress; furthermore, theserestorations were shown to have bothlow water absorption and water solubility.18 Silorane has also been shownto have good mechanical properties. 19,20The clinical application of these materialsis limited to the posterior teeth,however, because few low-translucentcolors are available. 2Some research in the dental literaturedoes not support the use of siloranebasedmaterials. In one clinical study,the marginal quality of the siloranecomposite was shown to be somewhatinferior to that of a nanohybrid composite.21 In another study, silorane didnot produce lower contraction stressthan other composites. 22As aforementioned, other monomerswith increased molecular weighthave been developed for compositeswith reduced shrinkage. Theurethane monomer TCD-DI-HEA(bis-(acryloyloxymethyl)tricyclo(5.2.1.02,6) decane), found in VenusDiamond and Venus Pearl, has beenshown to produce lower-curing contractionstress than other composites marketedas low-shrinking. 22 Other lowshrinkagematerials are available, suchas the modified urethane dimethacrylate(UDMA) resin from DuPont foundin Kalore, which has a relatively highmolecular weight compared to bisphenola glycidyl methacrylate (bis-GMA)and traditional UDMA. Another strategyis represented by dimer acid monomersused in N’Durance (Septodont;Lancaster, PA), which are also of relativelyhigh molecular weight and havebeen shown to have high conversion ofcarbon double bonds while undergoinglower polymerization shrinkage thanbis-GMA-based systems. 23,24Clinical ConsiderationsDirect AnteriorsIn anterior restorations, the materialmainly chosen, in many cases, is compositeresin. In the past, micro-particlecomposites were especially preferred fortheir good polishing, but they showedlow resistance to surface wearing.Considering the fairly favorable c-factor in anterior areas (Black Class IIIor IV cavities 25 ) (Fig 1); and knowingthat addictive morphological modificationsmay need to be made, thereis no strong clinical indication to uselow-shrinkage materials. Therefore, it ismore appropriate to focus on differentmaterials.In anterior restorations, the goalis mechanical and wear strength. Furthermore,from an adequate polishedsurface, nanohybrids and nanofilledmaterials are recommended today. Invitro scientific studies have shown thatvarious nanohybrids materials yield anexcellent surface quality 26,27 and havelow wear, thanks to increased wear resistance.28-30 The nanofilled materialsalso possess preferred mechanical properties,31 a relatively low shrinkage rate,and high strength. 32 These types of materialsprovide excellent results concerningsurface roughness. 33 Additionally,some technologies have been furtherdeveloped in this family of materials toimprove the maintenance of polishing,creating clusters with the nanoparticlesthat constitute the material (e.g., FiltekSupreme XTE).Another important point to consideris the esthetic behaviors of resin-basedmaterials. Considering the translucencyand opacity of both flowable and pastecomposites (generally photo-curable),it is advisable to choose the proper materialsto recreate the different areas ofnatural dentin and enamel. Some systemsoffer many composite masses withintermediate translucency, which arevery similar to one another, althoughthey are possibly deficient in translucencyeffects, intensives, and stains.The criteria of correct layering arealready well known. 34,35 Under normalconditions, the stratification of thecomposite provides in the most superficialarea an enamel that has goodtranslucency characteristics. This makesit possible to highlight the contrast betweenthe dentin and the translucenteffects placed under it in a natural manner(Figs 2-5).Another preferred feature, availablein some products currently on the market,is to have a composite light refractiveindex similar to natural tooth tissues.Generally, resin-based materialshave a lower refractive index; therefore,in equal thicknesses (composite andtooth), the optical behavior is different.Materials with a high refractive index(e.g., Enamel Plus HRi) provide an anatomicalstratification, with equal thicknessescompared to dental tissues.Lastly, in anterior composites a properfinishing is needed to emphasize themajor and minor morphologies, includinga multiple-step polishing usingburs, polishers, discs, and brushes,which helps smooth out rough surfacesand achieve depth perception. It wasdemonstrated that the surface finishedusing multiple-step polishing systemsJournal of Cosmetic Dentistry109

Figure 2: After gentle preparation, the isolation of the fieldand phosphoric etching are performed.Figure 3: Adhesive procedures on hard tissues.Figure 4: Palatal enamel is layered onto the dentin prior toapplying effects and the final enamel covering.Figure 5: A layer of composite is applied using a specialsilicone tip.Figure 6: A medium-grit polisher is used during the finishingprocedure.Figure 7: A fine-grit polisher is used during the finishingstage.110 Winter 2013 • Volume 28 • Number 4

FerrarisFigure 8: An aluminium oxide disc is employed during thefinishing stage.Figure 9: Diamond paste is applied with a brush during thepolishing stage.Figure 10: Final results one week after completion of therestoration.Figure 11: Final results shown via a different photographictechnique that highlights certain morphologies.Figure 12: The initial case. Amalgam reconstructions on #6and #7 and a composite filling on #5 will be replaced.Figure 13: The old filling and secondary carious lesions areremoved, and the cavity is prepared.Journal of Cosmetic Dentistry111

was superior to that obtained with onestepsystems, 36 and three-step rubberpolishers were more efficient than twostepand one-step polishing methodson nanoparticle and hybrid resin composites(Figs 6-11). 37Flowable materials, which are usuallyless filled and less viscous comparedto paste composites, often suffer fromhigh shrinkage. These materials couldbest be used in Black Class I, II, or V cavitiesand in areas of cavitated enamel. 38Direct and Indirect PosteriorsAs a posterior restorative, resin compositerepresents the primary choicetoday for most clinicians. In in vivostudies analyzing the prognosis of compositerestorations, with 10 to 20 yearsfollow-up, the annual failure rate waslow: approximately 2%. 39-41 Gaenglerand colleagues 39 described 10 yearsof follow-up of direct posterior compositewith the following conclusions:“The early risk of failure is attributed tobulk fractures and partial loss of fillingmaterial. The longevity over 10 yearsis a maximum of 74.2%, and the verylow secondary caries rate and the highpercentage of correct anatomical formconfirm the clinical safety of posteriorcomposite restorations.”In clinical studies that have comparedthe follow-up of posterior restorationswith amalgam and composite,the results are similar, although it canbe assumed that some amalgams have aslightly greater longevity. 42-44Another study with 12 years offollow-up involving high caries-riskpatients compared composite andamalgam restorations. Both materialsshowed higher failure rates, although inlarge cavities composite behaved betterin patients with a lower caries risk. 45Posterior composite restorationscan be made via a direct or indirecttechnique. It has been shown that, ina medium-sized cavity, indirect anddirect composite restorations have revealedno differences in performanceafter many years. 46 The cavity should beanalyzed carefully and a treatment evaluationshould be performed to determinewhich restoration is preferred, 47Figure 14: Etching phase during the adhesive procedure.Figure 15: The matrix has been positioned for the buildup of the interproximalwall. Some flowable composite was placed on the dentin to support thecervical residual enamel.Figure 16: The matrix from a buccal point of view, demonstrating therelationship between the wedge, matrix, and ring.112 Winter 2013 • Volume 28 • Number 4

FerrarisFigure 17: Completion of the layering of direct restorations.The composite buildup on #6 must now be finished.Figure 18: The cavity on #6 is prepared for the impression.Enamel margins are available on the full perimeter. Aretraction cord is positioned to the closest margins to thegingiva.Figure 19: Composite onlay before cementation.Figure 20: Adhesive treatments of composite onlays:sandblasting (left), silane (middle), and bonding (right).Figure 21: Cavity cleaning under rubber dam,before the adhesive cementation.Figure 22: Cavity etching with phosphoricacid.Journal of Cosmetic Dentistry113

Figure 23: Cavity bonding.Figure 24: Excess cement must beremoved during onlay cementation ofthe seating phase.Figure 25: Final results after one week showing a direct composite restoration on #5 and #7and an indirect onlay composite bonded on #6.and qualitative and quantitative evaluationsof the residual cavity structuresand the need to rebuild one or morecusps should be thoroughly considered.However, it is possible that teeth can bereconstructed within the same quadrantusing either a direct or indirect technique(Figs 12-25).Direct posterior restorations aremore susceptible to shrinkage stresscompared to indirect restorations;hence, it may be desirable to use a materialwith low shrinkage and a favorableelasticity modulus. Furthermore,to minimize these negative effects, itis recommended to use an appropriatelayering technique followed by propercuring for each layer.In Black Class II cavities, positioninga sectional matrix can help providea correct point of contact and resultin a good interproximal morphology(Figs 15 & 16).Composite resins are also indicatedin indirect onlays (Figs 17 & 18). Somein vitro studies have compared indirectonlays with ceramic restorations andfound that fracture resistance, when applyinga normal masticatory load, wassimilar for both materials. With masticatoryoverload, however, the compositegave better results in terms ofresistance and distribution of stress onthe root below. In addition, compositeresins layered and milled with CAD/CAM technology showed higher fatigueresistance than porcelain. 48,49 Otherdesirable features of composite resinsinclude better management of the morphologyand less shrinkage of the material,which is polymerized out of thecavity (Fig 19).Indirect composite restorations canbe cemented adhesively, thanks to pretreatmentsand proper procedures. Unlikecemented porcelain restorations,indirect composite restorations aresandblasted (using aluminium oxideor silica coating) and not treated withhydrofluoric acid. 50,51 The pre-treatmentbefore the resin cement (that can belight-curable) can be represented bysilane and hydrophobic resinous bonding(Figs 20-25).114 Winter 2013 • Volume 28 • Number 4

27. Silikas N, Kavvadia K, Eliades G, Watts D. Surfacecharacterization of modern resin composites:a multi-technique approach. Am J Dent.2005;18(2):95-100.36. Watanabe T, Miyazaki M, Moore BK. Influenceof polishing instruments on the surfacetexture of resin composites. Quintessence Int.2006;37(1):61-7.versus compomer/composite restorations inposterior primary and permanent teeth: findingsfrom the New England Children’s AmalgamTrial. J Am Dent Assoc. 2007;138:763-72.28. Turssi CP, Ferracane JL, Serra MC. Abrasivewear of resin composites as related to finishingand polishing procedures. Dent Mater.2005;21(7):641-8.29. Yap AU, Tan CH, Chung SM. Wear behaviorof new composite restoratives. Oper Dent.2004;29(3): 269-74.30. Xu HH, Quinn JB, Giuseppetti AA. Wearand mechanical properties of nano-silica-fusedwhisker composites. J Dent Res.2004;83(12):930-5.31. Mitra SB, Wu D, Holmes BN. An application ofnanotechnology in advanced dental materials.J Am Dent Assoc. 2003;134(10):1382-90.32. Chen MH, Chen CR, Hsu SH, Sun SP, Su WF.Low shrinkage light curable nanocompositefor dental restorative material. Dent Mater.2006;22(2):138-45.33. Janus J, Fauxpoint G, Arntz Y, Pelletier H, EtienneO. Surface roughness and morphologyof three nanocomposites after two differentpolishing treatments by a multitechnique approach.Dent Mater. 2010;26(5):416-25.34. Vanini L. Light and color in anterior compositerestorations. Pract Periodontics Aesthet Dent.1996 Sep;8(7):673-82; quiz 684.35. Dietschi D. Layering concepts in anteriorcomposite restorations. J Adhes Dent. 2001Spring;3(1):71-80.37. Jung M, Voit S, Klimek J. Surface geometry ofthree packable and one hybrid composite afterfinishing. Oper Dent. 2003;28(1):53-9.38. Yacizi AR, Ozgunaltay G, Dayangac B. The effectof different types of flowable restorativeresins on microleakage of Class V cavities.Oper Dent. 2003;28:773-8.39. Gaengler P, Hoyer I, Montag R. Clinical evaluationof posterior composite restorations: the10-year report. J Adhes Dent. 2001;3:185-94.40. Pallesen U, Qvist V. Composite resin fillingsand inlays. An 11-year evaluation. Clin OralInvest. 2003;7:71-9.41. DaRosa Rodolpho PA, Cenci MS, DonassolloTA, Loguércio AD, Demarco FF. A clinical evaluationof posterior composite restorations: 17-year findings. J Dent. 2006;34:427-35.42. Van Nieuwenhuysen JP, D’Hoore W, CarvalhoJ, Qvist V. Long-term evaluation of extensiverestorations in permanent teeth. J Dent.2003;31:395-405.43. Bernardo M, Luis H, Martin MD, Leroux BG,Rue T, Leitão J, DeRouen TA. Survival and reasonsfor failure of amalgam versus compositeposterior restorations placed in a randomizedclinical trial. J Am Dent Assoc. 2007;138:775-83.44. Soncini JA, Maserejian NN, Trachtenberg F, TavaresM, Hayes C. The longevity of amalgam45. Opdam NJ, Bronkhorst EM, Loomans BA,Huysmans MC. Twelve-year survival of compositevs. amalgam restorations. J Dent Res.2010 Oct;89(10):1063-7. Epub July 26, 2010.46. Spreafico RC, Dietschi D, Kreijci I. Clinical performanceand marginal adaption of Class II directand semi-direct composite restorations. JDent. 2005 Jul;33(6):499-507.47. Fichera G, Devoto W, Re D. Cavity configurationsfor indirect partial coverage adhesivecementedrestorations. Hanover Park (IL):Quintessence Pub.; 2006:55-67.48. Magne P, Knezevic A. Simulated fatigue resistanceof composite resin versus porcelainCAD/CAM overlay restorations on endodonticallytreated molars. Quintessence Int. 2009Feb;40(2):125-33.49. Magne P, Knezevic A. Influence of overlay restorativematerials and load cusps on the fatigueresistance of endodontically treated molars.Quintessence Int. 2009 Oct;40(9):729-37.50. Swift EJ Jr, Brodeur C, Cvitko E, Pires JA. Treatmentof composite surfaces for indirect bonding.Dent Mater. 1992 May;8(3):193-6.51. Valandro LF, Pelogia F, Galhano G, BottinoMA, Mallmann A. Surface conditioning of acomposite used for inlay/onlay restorations:effect on muTBS to resin cement. J Adhes Dent.2007 Dec;9(6):495-8. jCDDr. Ferraris is an active member of the European Academy of Esthetic Dentistryand of the Italian Academy of Conservative Dentistry. He is visiting professorof esthetic dentistry at the University of San Pablo-CEU in Madrid, Spain. Dr.Ferraris lectures internationally and practices in Alessandria, Italy.Disclosure: The author did not report any disclosures116 Winter 2013 • Volume 28 • Number 4

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