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Cytotoxicity evaluation of new resin matrix system on fiber-reinforced composites
e61
d e n t a l m a t e r i a l s 2 9 S ( 2 0 1 3 ) e1–e96
without compromising mechanical properties. Introduction of reinforcing filler does not interfere with the nanogel-based stress reduction potential. Support: NIH/NIDCR-R01DE022348.
Matrix composition
Percentage of cells viability (mean ± s.d.)
Exp-1 group Exp-2 group Control group
67.73 ± 0.71 66.78 ± 0.20 64.36 ± 1.63
http://dx.doi.org/10.1016/j.dental.2013.08.124 124 Cytotoxicity evaluation of new resin matrix system on fiber-reinforced composites S. Sunarintyas 1,∗ , W. Siswomihardjo 1 , H. Suwarsohartono 1 , J.P. Matinlinna 2
http://dx.doi.org/10.1016/j.dental.2013.08.125 125
1
Universitas Gadjah Mada, Indonesia 2 University of Hong Kong, Hong Kong
Purpose: Recent commercial resin matrix systems use bisGMA as the basic matrix. A previous studies showed that bis-GMA affected the vitality of dental pulp and induced pulpal inflammation (Engelmann J, et al. Biomaterials 2004;25:4573), was able to disturb normal differentiation procedures of pulp fibroblasts (Imazato S, et al. J Biomed Mater Res Part B: Appl Biomater 2009;88B:378), and induced allergic contact stomatitis (Stoeva et al. J IMAB-Ann Proc 2008;book 2:45). A monomer alternative to bis-GMA, such as 1,6-hexanediol dimethacrylate (HDMA), is under current research. The purpose of this study was to determine the cytotoxicity property of HDMA on fibroblast cells by MTT method. Methods and materials: The materials used were bis-GMA (Sigma–Aldrich, USA), MMA (ProSciTech, Australia), HDMA (Esstech, USA), CQ (Esstech, USA), CEMA (Esstech, USA), Eglass fibers (Stick Tech, Finland), Vero fibroblast cell line (UGM, Indonesia). Fifteen specimens of FRCs (2 × 2 × 25) mm were prepared and divided into 3 groups. The experiment groups were 78.4%HDMA + 19.6%MMA + 1.0%CQ + 1.0%CEMA (Exp-1 group) and 49.0%HDMA + 49.0%MMA + 1.0%CQ + 1.0%CEMA Exp-2 group), whilst the control group was 78.4%bisGMA + 19.6%MMA + 1.0%CQ + 1.0%CEMA. Specimens were milled and diluted in culture medium (0.1 mg powder/1 mL medium). Specimen solution of 100 L was added into 96-well plate containing fibroblast cells of 2 × 104 cells/100 L and incubated for 24 h. MTT of 10 L was added to the well, incubated for 4 h, then 100 L stop solution was added. The OD of the cells viability was determined by a ELISA reader with a wavelength of 550 nm. Cells viability was calculated in percentage and analyzed by ANOVA and LSD. Results: Analysis by one way ANOVA revealed significant differences of cells viability among the groups (p < 0.01). The LSD test showed a significant difference between exp-1 group and control group and also between exp-2 group and control group (p < 0.01), whilst no significant difference between exp-1 group and exp-2 group was found (p > 0.05). Conclusion: A resin matrix system based on HDMA–MMA (exp-1 group and exp-2 group) revealed a significant difference of fibroblast cells viability compared to a bis-GMA–MMA matrix system. The HDMA–MMA matrix system was less cytotoxic than bis-GMA–MMA matrix system. Average of fibroblast cells viability in percentage (%)
Edge chipping test on microhybrid and nanocomposites C.B. Tanaka 1,∗ , R.Y. Ballester 1 , G. De Souza 2 , Y. Zhang 3 , J.B.C. Meira 1 1
University of São Paulo, Brazil University of Toronto, Canada 3 New York University, USA 2
Purpose: The edge chipping test has been considered a practical and reliable test to evaluate “edge toughness” and “edge strength” of dental ceramics. The aim of this study was to investigate the influence of indenter type on the “edge toughness (Te)” of two different restorative composites. Methods and materials: A microhybrid composite, (Z250 – Filtek Supreme XT, 3M-ESPE, MN) and a nanocomposite (Z350 – Filtek Supreme XT, 3M-ESPE, MN) were used to prepare 3 bars (5 × 32 × 2.5 mm) samples for each material. The specimens were light-cured using a LED (light-emitting diode) with an irradiance of 1200 mW/cm2 (RADII CAL SDI, Bayswater, AUS). Three base increments were photo-activated for 20 s each and a final surface increment for 120 s. Specimens were kept for 7 days in water-storage at 37 ◦ C before being tested. The edge chipping tests were carried out using a universal testing machine, with a constant load (0.1 mm/min). Two indenter types were used: Rockwell (conical 120◦ ) and Vickers. The load was applied in different distances between the upper longitudinal edge and the indenter (da). Each specimen was chipped around twenty times, with five different da values, from 0.1 mm to 0.5 mm. An average force and standard deviation were calculated for each distance. The relationship between mean critical force (Fc) and edge distance (da) was plotted. Edge toughness (Te) was defined as the slope of the linear trend on these graphs. Results: The results showed that highest values of edge toughness was found using Vickers indenter. Differences between composite (Z250 Te = 335.9 N/mm and Z350 Te = 277.5 N/mm) were found with Vickers indenter, but not with Rockwell indenter (Z250 Te = 234.9 N/mm and Z350 Te = 235.0 N/mm). Conclusion: The type of indenter influences on edge toughness value. Vickers indenter was able to distinguish the different composite, while Rockwell indenter showed similar toughness for them.
d e n t a l m a t e r i a l s 2 9 S ( 2 0 1 3 ) e1–e96
without compromising mechanical properties. Introduction of reinforcing filler does not interfere with the nanogel-based stress reduction potential. Support: NIH/NIDCR-R01DE022348.
Matrix composition
Percentage of cells viability (mean ± s.d.)
Exp-1 group Exp-2 group Control group
67.73 ± 0.71 66.78 ± 0.20 64.36 ± 1.63
http://dx.doi.org/10.1016/j.dental.2013.08.124 124 Cytotoxicity evaluation of new resin matrix system on fiber-reinforced composites S. Sunarintyas 1,∗ , W. Siswomihardjo 1 , H. Suwarsohartono 1 , J.P. Matinlinna 2
http://dx.doi.org/10.1016/j.dental.2013.08.125 125
1
Universitas Gadjah Mada, Indonesia 2 University of Hong Kong, Hong Kong
Purpose: Recent commercial resin matrix systems use bisGMA as the basic matrix. A previous studies showed that bis-GMA affected the vitality of dental pulp and induced pulpal inflammation (Engelmann J, et al. Biomaterials 2004;25:4573), was able to disturb normal differentiation procedures of pulp fibroblasts (Imazato S, et al. J Biomed Mater Res Part B: Appl Biomater 2009;88B:378), and induced allergic contact stomatitis (Stoeva et al. J IMAB-Ann Proc 2008;book 2:45). A monomer alternative to bis-GMA, such as 1,6-hexanediol dimethacrylate (HDMA), is under current research. The purpose of this study was to determine the cytotoxicity property of HDMA on fibroblast cells by MTT method. Methods and materials: The materials used were bis-GMA (Sigma–Aldrich, USA), MMA (ProSciTech, Australia), HDMA (Esstech, USA), CQ (Esstech, USA), CEMA (Esstech, USA), Eglass fibers (Stick Tech, Finland), Vero fibroblast cell line (UGM, Indonesia). Fifteen specimens of FRCs (2 × 2 × 25) mm were prepared and divided into 3 groups. The experiment groups were 78.4%HDMA + 19.6%MMA + 1.0%CQ + 1.0%CEMA (Exp-1 group) and 49.0%HDMA + 49.0%MMA + 1.0%CQ + 1.0%CEMA Exp-2 group), whilst the control group was 78.4%bisGMA + 19.6%MMA + 1.0%CQ + 1.0%CEMA. Specimens were milled and diluted in culture medium (0.1 mg powder/1 mL medium). Specimen solution of 100 L was added into 96-well plate containing fibroblast cells of 2 × 104 cells/100 L and incubated for 24 h. MTT of 10 L was added to the well, incubated for 4 h, then 100 L stop solution was added. The OD of the cells viability was determined by a ELISA reader with a wavelength of 550 nm. Cells viability was calculated in percentage and analyzed by ANOVA and LSD. Results: Analysis by one way ANOVA revealed significant differences of cells viability among the groups (p < 0.01). The LSD test showed a significant difference between exp-1 group and control group and also between exp-2 group and control group (p < 0.01), whilst no significant difference between exp-1 group and exp-2 group was found (p > 0.05). Conclusion: A resin matrix system based on HDMA–MMA (exp-1 group and exp-2 group) revealed a significant difference of fibroblast cells viability compared to a bis-GMA–MMA matrix system. The HDMA–MMA matrix system was less cytotoxic than bis-GMA–MMA matrix system. Average of fibroblast cells viability in percentage (%)
Edge chipping test on microhybrid and nanocomposites C.B. Tanaka 1,∗ , R.Y. Ballester 1 , G. De Souza 2 , Y. Zhang 3 , J.B.C. Meira 1 1
University of São Paulo, Brazil University of Toronto, Canada 3 New York University, USA 2
Purpose: The edge chipping test has been considered a practical and reliable test to evaluate “edge toughness” and “edge strength” of dental ceramics. The aim of this study was to investigate the influence of indenter type on the “edge toughness (Te)” of two different restorative composites. Methods and materials: A microhybrid composite, (Z250 – Filtek Supreme XT, 3M-ESPE, MN) and a nanocomposite (Z350 – Filtek Supreme XT, 3M-ESPE, MN) were used to prepare 3 bars (5 × 32 × 2.5 mm) samples for each material. The specimens were light-cured using a LED (light-emitting diode) with an irradiance of 1200 mW/cm2 (RADII CAL SDI, Bayswater, AUS). Three base increments were photo-activated for 20 s each and a final surface increment for 120 s. Specimens were kept for 7 days in water-storage at 37 ◦ C before being tested. The edge chipping tests were carried out using a universal testing machine, with a constant load (0.1 mm/min). Two indenter types were used: Rockwell (conical 120◦ ) and Vickers. The load was applied in different distances between the upper longitudinal edge and the indenter (da). Each specimen was chipped around twenty times, with five different da values, from 0.1 mm to 0.5 mm. An average force and standard deviation were calculated for each distance. The relationship between mean critical force (Fc) and edge distance (da) was plotted. Edge toughness (Te) was defined as the slope of the linear trend on these graphs. Results: The results showed that highest values of edge toughness was found using Vickers indenter. Differences between composite (Z250 Te = 335.9 N/mm and Z350 Te = 277.5 N/mm) were found with Vickers indenter, but not with Rockwell indenter (Z250 Te = 234.9 N/mm and Z350 Te = 235.0 N/mm). Conclusion: The type of indenter influences on edge toughness value. Vickers indenter was able to distinguish the different composite, while Rockwell indenter showed similar toughness for them.