Malaysian Abstracting and Indexing SystemPost-polymerization of dental resin composite evaluated with nanoindentation and micro-Raman spectroscopy Mohamad, Dauthor Young, R.J. author Mann, A.B. author Watts, D.C. authorThe 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.R Medicine, Dentistry, Pharmacy, Nursing2007School of Dental Sciences, Universiti Sains MalaysiaJournal

For work being deposited by its own author: In self-archiving this collection of files and associated bibliographic metadata, I grant Malaysian Abstracting and Indexing System the right to store them and to make them permanently available publicly for free on-line. I declare that this material is my own intellectual property and I understand that Malaysian Abstracting and Indexing System does not assume any responsibility if there is any breach of copyright in distributing these files or metadata. (All authors are urged to prominently assert their copyright on the title page of their work.)

For work being deposited by someone other than its author: I hereby declare that the collection of files and associated bibliographic metadata that I am archiving at Malaysian Abstracting and Indexing System) is in the public domain. If this is not the case, I accept full responsibility for any breach of copyright that distributing these files or metadata may entail.

Clicking on the deposit button indicates your agreement to these terms.