1601 17 archive 85 disk0/00/00/16/01 2008-02-02 09:36:17 2008-02-02 09:36:17 2008-02-02 09:36:17 article show dasmawati@kck.usm.my Mohamad, D dasmawati@kck.usm.my Young, R.J. Mann, A.B. Watts, D.C. Universiti Sains Malaysia. School of Dental Sciences University of Manchester. School of Materials. Manchester Materials Science Centre University of Manchester. School of Materials. Manchester Materials Science Centre University of Manchester. School of Dentistry. Biomaterials Science Unit pub R public Nanoindentation, dental composite, Young’s modulus, hardness, degree of conversion This article is based on a dissertation submitted to the Manchester Materials Science Centre, UMIST, in partial requirements for the MSc degree. The aim of the study was to evaluate post-polymerization of resin composite by measuring NanoHardness (H), Young’s Modulus (E) and Degree of Conversion (DC) using nanoindentation and Micro-Raman spectroscopy. For this purpose a computer-controlled NanoIndenter and a Renishaw 1000 Raman Spectrometer fitted with an Olympus microscope attachment, operated at 638 nm, were used. A light- activated resin composite was used in this study, (Z250, 3MESPE). Sub-groups (n=3) of specimens were irradiated for 20, 30, 40 s. All samples for nanoindentation were polished metallographically and typically 50 nano-indentations were performed per specimen. After curing and polishing, half of the samples were tested immediately (Group 1); the others after being stored dry at 37 C for 7 days (Group 2) to allow scope for post-polymerization. H values ranged from 1.08 to 1.40 GPa for Group 1, and from 1.64 to1.71 GPa for Group 2. E values in Group 1 ranged from 19.60 to 19.94 GPa and for Group 2, from 21.42 to 22.05 GPa. DC values ranged from 55 to 66.39%, and 60.90 to 66.47% for Group 1 and Group 2 respectively. 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Post-irradiation polymerization of composites containing bis-GMA and TEGDMA. Dent Mater, 15: 238-242. Van Meerbeek B, Willems G, Celis JP, Roos JR, Braem M, Lambrechts P,and Vanherle G (1993). Assessment by nanoindentation of the hardness and elasticity of the resin-dentin bonding area. J. Dent Res, 72(10): 1434-1442. Willems G, Celis JP, Lambrechts P, Braem M, and Vanherle G (1993) Hardness and Young’s Modulus determined by nanoindentation technique of filler particles of dental restorative materials compared with human enamel. J Biomed Mater Res, 27: 747-755. Xu HHK, Smith DT, Jahanmir S, Romberg E, Kelly JR, Thompson VP and Rekow ED (1998) Indentation damage and mechanical properties of human enamel and dentin. J Dent Res, 77 (33): 472-480. 144 3 1601 1 application/pdf en public

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