PENGARUH PENAMBAHAN POLYETHYLENE FIBER TERHADAP KONSENTRASI SISA MONOMER PADA FIBER REINFORCED COMPOSITE JENIS POLYETHYLENE FIBER

Fiber reinforced composite is a material consisted of matrix and reinforcing fiber. There is great interest in the development of FRC in dentistry as an alternative material with minimally preparation for teeth and it has good mechanical properties. Polyethylene fiber is a type of fiber which is commonly used because it has good mechanical. Polymerization of resin-based composite will never reach 100%, thus resulting in residual monomer. The amount of residual monomer affects the mechanical properties and bicompatibility of a material. This study was conducted to investigate the effects of polyethylene fiber addition to residual monomer concentration in fiber reinforced composite. Polyethylene fiber (CONSTRUCT KerrTM, USA) and composite resin Masterflow ® (Biodinamica, Brazil) were used. There were two groups. Group one was composite resin and group two was composite resin with the addition of polyethylene fiber. Each material was inserted into the mold (size 2x2x25mm), then cured by visible light cure for 20 seconds, then powdered 75 mg of the sample powder was diluted in acetonitrile to reach a volume of 5 ml for each group. Magnetic stirrer was used to dissolve the solution for 72 hours. The sample solution was filtered with a milipore 0.45 μm and then injected into the HPLC as much as 20 μL. Residual monomer was analyzed using the mobile phase of acetonitrile and water with a 7:3 ratio, flow rate of 1 mL/minute at room temperature. The size of column was C18 5 μm, length 125 mm, and 4 mm in diameter. UV detection using 220 nm wavelength was performed. The data were analyzed by t-test. The average concentration of residual monomer of the composite resin was 0.044601 ± 0.00234 and the polyethylene FRC was 0.017861 ± 0.00068. Test t-test result showed a significant difference between the two treatment groups (�<0.05). It could be concluded that the addition of polyethylene fiber to composite resin reduced the concentration of residual monomer. Keywords : polyethylene, FRC, residual monomer, HPLC, bis-GM