Long-Term Surface Hardness and Monomer Conversion of a Nanofilled and a Microhybrid Composite Resin
Mateus Rodrigues Tonetto, Matheus Coelho Bandéca, José Roberto Cury Saad, Edson Alves de Campos, Fernanda Ferreira Jassé, Carlos Henrique Braga Borges, Alessandra Nara de Souza Rastelli, Vanderlei Salvador Bagnato, Reidson Stanley Soares dos Santos
Citation Information :
Tonetto MR, Bandéca MC, Saad JR, de Campos EA, Jassé FF, Borges CH, de Souza Rastelli AN, Bagnato VS, Santos RS. Long-Term Surface Hardness and Monomer Conversion of a Nanofilled and a Microhybrid Composite Resin. J Contemp Dent Pract 2013; 14 (5):876-882.
This study aims to evaluate the degree of conversion (DC) and hydrolytic degradation through the Vickers hardness test (HV) of a nanofilled (FiltekTM Z-250, 3M) and a microhybrid (FiltekTMSupreme-XT, 3M) composite resin.
Materials and methods
Eight disk-shaped specimens (4 mm diameter × 2 mm thick, ISO 4049) of each material were prepared for each test. Composites were inserted into single increment in a metallic matrix and light-cured for 40 seconds. VH readings were performed for each specimen at predetermined intervals: immediately after polymerization (control), 1, 2, 3, 7, 14, 21, 30 and 180 days. After curing, initial hardness measurements were performed and the specimens were immersed in artificial saliva at 37°C. For DC (%), specimens were ground, pressed with KBr and analyzed by FT-IR spectrophotometer.
Student t-test showed that there was no difference between the resins for DC (p = 0.252). ANOVA analysis revealed that Z-250 VH means were all greater than S-XT, for both top and bottom surfaces, whatever the storage-period in artificial saliva (p < 0.001). After 180 days of storage, the hardness obtained for S-XT was similar with that at the baseline, for both top and bottom surfaces. While for Z-250 hardness was not significantly different from baseline only for top surface, but there was a significant decrease observed in hardness for bottom surface.
The materials tested showed no evidence of hydrolytic degradation in a significant way, in a 6-month storagetime in artificial saliva. Nanofilled resin presents a monomer conversion comparable to the conventional microhybrid.
How to cite this article
Jassé FF, Borges CHB, Tonetto MR, de Souza Rastelli AN, Bagnato VS, de Campos EA, Bandeca MC, Saad JRC. Long-Term Surface Hardness and Monomer Conversion of a Nanofilled and a Microhybrid Composite Resin. J Contemp Dent Pract 2013;14(5):876-882.
Effects of monomer ratios and highly radiopaque fillers on degree of conversion and shrinkage-strain of dental resin composites. Dent Mater 2009;25:1411-1418.
Effects of light curing method and exposure time on mechanical properties of resin based dental materials. Eur J Dent 2008;2:37-42.
Infrared spectroscopy: a tool for determination of the degree of conversion in dental composites. J Appl Oral Sci 2008;16:145-149.
Relationship between the degree of conversion, solubility and salivary sorption of a hybrid and a nanofilled resin composite: influence of the light-activation mode. J Appl Oral Sci 2008;16:161-166.
Influence of UEDMA BisGMA and TEGDMA on selected mechanical properties of experimental resin composites. Dent Mater 1998;14:51-56.
Properties of silica reinforced polymer of dental restorations. J Am Dent Assoc 1963;1:57-64.
Resin composites in dentistry: the monomer systems. Eur J Oral Sci 1997;105:97-116.
Correlation between degree of conversion, filler concentration and mechanical properties of posterior composite resins. J Oral Rehabil 1990;17:487-494.
Relationship between the degree of conversion and internal discoloration of light-activated composite. Dent Mater J 1995;14:23-30.
Influence of lightpolymerization modes on the degree of conversion and mechanical properties of resin composites: a comparative analysis between a hybrid and a nanofilled composite. Oper Dent 2008;33:287-293.
Study of water sorption, solubility and modulus of elasticity of light-cured dimethacrylate-based dental resins. Biomaterials 2003;24:655-665.
Effects of various resin composite (co) monomers and extracts on two cariesassociated micro-organisms in vitro. J Dent Res 1998;77:60-67.
Allergic contact dermatitis to bisphenol-A-glycidyldimethacrylate (Bis-GMA) dental resin associated with sensitivity to epoxy resin. Br Dent J 1997;183:297-298.
The effect of filler and silane content on conversion of resin-based composite. Dent Mater 2003;19:327-333.
Fourier transform infrared analysis of degree of polymerization in unfilled resins -methods comparison. J Dent Res 1984;8:1093-1095.
Influence of light source and extended time of curing on microhardness and degree of conversion of different regions of a nanofilled composite resin. Eur J Dent 2012;6:153-157.
Surface hardness change of restorative filling materials stored in saliva. Dent Mater 2001;17:34-39.
Bastian FL. Influence of artificial saliva on abrasive wear and microhardness of dental composites filled with nanoparticles. J Dent 2008;36:703-710.
Influence of pH environment on polymer based dental material properties. J Dent 2005;33:91-98.
Effects of storage time and temperature on the properties of two self-etching systems. J Dent 2007;35:218-225.
Chemical degradation of composite restoratives. J Oral Rehabil 2001;28:1015-1021.
Hydrolytic degradation of dental composites. J Dent Res 1984;63:1248-1254.
Long-term surface micro-hardness of resin-modified glass ionomers. J Dent 1998;26:707-712.
Photoinitiator content in restorative composites: influence on degree of conversion, reaction kinetics, volumetric shrinkage and polymerization stress. Am J Dent 2009;22:206-210.
Bis-GMA copolymerizations: influence on conversion, flexural properties, fracture toughness and susceptibility to ethanol degradation of experimental composites. Dent Mater 2009;25:1136-1141.
Influence of photoinitiator type on the rate of polymerization, degree of conversion, hardness and yellowing of dental resin composites. Dent Mater 2008;24:1169-1177.
Monomer systems for dental composites and their future: a review. J Calif Dent Assoc 2009;37:389-398.
Characterization of water sorption, solubility and filler particles of light-cured composite resins. Braz Dent J 2009;20:314-318.
Characterization of nanofilled compared to universal and microfilled composites. Dent Mater 2007;23:51-59.
Filler features and their effects on wear and degree of conversion of particulate dental resin composites. Biomaterials 2005;26:4932-4937.
The effect of filler loading and morphology on the mechanical properties of contemporary composites. J Prosthet Dent 2002;87:642-649.
Effect of preheating resin composite and light-curing units on monomer conversion. Laser Phys 2010;20:285-290.
Flexural strength and modulus of elasticity of different types of resin-based composites. Braz Oral Res 2007;21:16-21.
Spectroscopic and mechanical properties of dental resin composites cured with different light sources. J Mol Struct 2005;744-7:641-646.
The effect of resin formulation on the degree of conversion and mechanical properties of dental restorative resins. J Biomed Mater Res 1986;20:121-131.
Degree of conversion and temperature increase of a composite resin light cured with an argon laser and blue LED. Laser Phys 2008;18:1570-1575.
Correlation between hardness and degree of conversion during the setting reaction of unfilled dental restorative resins. Dent Mater 1985;1:11-14.
Light intensity effects on resin composite degree of conversion and shrinkage strain. Dent Mater 2000;16:292-296.
Influence of different light sources and photoactivation methods on degree of conversion and polymerization shrinkage of a nanocomposite resin. Laser Phys 2009;19:2210-2218.
The diffusion kinetics of a nanofilled and a midifilled resin composite immersed in distilled water, artificial saliva, and lactic acid. Clin Oral Invest 2011;15(3):393-401.
Influence of pre-heat treatment and different light-curing units on vickers hardness of a microhybrid composite resin. Laser Phys 2009;19:1276-1281.
Surface microhardness of a resin composite exposed to a ‘firstgeneration’ LED curing lamp, in vitro. Eur J Prosthodont Restor Dent 2004;12:177-180.
Effect of base monomer's refractive index on curing depth and polymerization conversion of photo-cured resin composites. Dent Mater J 2005;24:403-408.
Influence of polymerization time of different composites on water sorption. Rev Odonto Ciênc 2008;23:67-71.
Relaxation of polymerization contraction shear stress by hygroscopic expansion. J Dent Res 1990;69:36-39.
Initial dimension change of composites in dry and wet conditions. J Dent Res 1983;62:28-31.
Filler leachability of composites stored in distilled water or artificial saliva. J Dent Res 1996;75:1692-1699.
Water sorption and mechanical properties of light-cured proprietary composite tooth restorative materials. Biomaterials 1992;13:105-109.
Chemical and morphological features of dental composite resin: influence of light curing units and immersion media. Microsc Res Techniq 2010;73:176-181.