• Title/Summary/Keyword: GMA

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SURFACE ROUGHNESS OF EXPERIMENTAL COMPOSITE RESINS USING CONFOCAL LASER SCANNING MICROSCOPE (공초점 레이저 주사 현미경을 이용한 실험적 레진의 표면 조도에 대한 연구)

  • Bae, J.H.;Lee, M.A.;Cho, B.H.
    • Restorative Dentistry and Endodontics
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    • v.33 no.1
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    • pp.1-8
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    • 2008

  • The purpose of this study was to evaluate the effect of a new resin monomer, filler size and polishing technique on the surface roughness of composite resin restorations using confocal laser scanning microscopy. By adding new methoxylated Bis-GMA (Bis-M-GMA, 2,2-bis[4-(2-methoxy-3-methacryloyloxy propoxy) phenyl] propane) having low viscosity, the content of TEGDMA might be decreased. Three experimental composite resins were made: EX1 (Bis-M-GMA/TEGDMA = 95/5 wt%, 40 nm nanofillers); EX2 (Bis-M-GMA/TEGDMA = 95/5 wt%, 20 nm nanofillers); EX3 (Bis-GMA/TEGDMA = 70/30 wt%, 40 nm nanofillers). Filtek Z250 was used as a reference. Nine specimens (6 mm in diameter and 2 mm in thickness) for each experimental composite resin and Filtek Z250 were fabricated in a teflon mold and assigned to three groups. In Mylar strip group, specimens were left undisturbed. In Sof-lex group, specimens were ground with #1000 SiC paper and polished with Sof-lex discs. In DiaPolisher group, specimens were ground with #1000 SiC paper and polished with DiaPolisher polishing points. The Ra (Average roughness), Rq (Root mean square roughness), Rv (Valley roughness), Rp (Peak roughness), Rc (2D roughness) and Sc (3D roughness) values were determined using confocal laser scanning microscopy. The data were statistically analyzed by Two-way ANOVA and Tukey multiple comparisons test (p = 0.05). The type of composite resin and polishing technique significantly affected the surface roughness of the composite resin restorations (p < 0.001). EX3 showed the smoothest surface compared to the other composite resins (p < 0.05). Mylar strip resulted in smoother surface than other polishing techniques (p < 0.05). Bis-M-GMA. a new resin monomer having low viscosity, might reduce the amount of diluent, but showed adverse effect on the surface roughness of composite resin restorations.

  • https://doi.org/10.5395/JKACD.2008.33.1.001 인용 PDF KSCI

Synthesis of Sulfonated PET-g-GMA Fine Ion-exchange Fibers for Water Treatment by Photopolymerization and Their Adsorption Properties for Metal Ions (광중합법을 이용한 수처리용 설폰산형 PET-g-GMA 극세 이온 교환 섬유의 합성 및 금속 이온 흡착 특성)

  • Kwak Noh-Seok;Hwang Taek-Sung;Kim Sun-Mi;Yang Yun-Kyu;Kang Kyung-Seok
    • Polymer(Korea)
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    • v.28 no.5
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    • pp.397-403
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    • 2004

  • The sulfonated PET-g-GMA ion-exchange fine fibers were synthesized by UV radiation-induced graft copolymerization using a photoinitiator, and their chemical structure and adsorption properties were investigated. The optimum values for synthetic conditions - UV intensity, reaction time, and reaction temperature were 450 W, 60 min, and $40^{\circ}C$, respectively. Maximum values of the degree of sulfonation and ion exchange capacity were 8.12 mmol/g and 3.25 meq/g, respectively. Tensile strength of sulfonated PET-g-GMA fine ion exchange fibers was lower than that of PET trunk polymer as the grafting reaction rates increased. It was shown that as for the adsorption rate of $Ca^{2+}$ and $Mg^{2+}$ by the sulfonated PET-g-GMA fine ion exchange fibers, magnesium ion is slower than calcium ion in the solution. However, in the mixture of the calcium and magnesium ions, the adsorption rate of calcium ion was much slower than that of magnesium ion.

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