http://myais.fsktm.um.edu.my/1601/ Post-polymerization of dental resin composite evaluated with nanoindentation and micro-Raman spectroscopy Mohamad, D, Young, R.J. , Mann, A.B. , Watts, D.C. , R Medicine, Dentistry, Pharmacy, Nursing 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. All values obtained shown significant different between Groups 1 and 2 (p<0.05); ie as a result of any (further) monomer post- polymerization. The consistently greater H, E and DC values in Group 2 suggest that network stabilization may occur partly by mechanisms supplementary to monomer conversion per se. This could include annealing of the polymer chain segments. School of Dental Sciences, Universiti Sains Malaysia 2007 Journal PeerReviewed application/pdf http://myais.fsktm.um.edu.my/1601/1/2631_Dasmawati.pdf http://www.kck.usm.my/ppsg/official-journal.htm Mohamad, D, and Young, R.J. , and Mann, A.B. , and Watts, D.C. , (2007) Post-polymerization of dental resin composite evaluated with nanoindentation and micro-Raman spectroscopy. Archives of Orofacial Sciences, 2 . pp. 26-31. ISSN 1823-8602 http://myais.fsktm.um.edu.my/1601/http://myais.fsktm.um.edu.my/1601/1/