PENGARUH JUMLAH LAPISAN FIBER ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE (UHMWPE) PADA FIBER REINFORCED COMPOSITE TERHADAP PENYERAPAN AIR

Fiber-reinforced composite (FRC) is a material which is combination of polymer matrix and fiber. The use of FRC in the oral cavity causing interactions between FRC with saliva which is mostly water constituent. This study aimed to determine the effect of adding layers UHMWPE fiber in FRC towards water absorption. Speciments in this research were FRC with UHMWPE fibers braided form (CONSTRUCT Kerr�, USA) and flowable composite matrix (Master Flow BIODINAMICA, Brazil). Based on ISO 10477, the sample size used were 2mm x 2mm x 25mm which were activated by visible light source (blue-LED, litex 695tm, Dentamerica, USA) for 20 secons for each surface as wide as the tip of irradiation. The speciments were divided into three treatment groups, they were group without fiber (5 speciments), FRC with 1 layer of fiber (7 speciments) and FRC with 2 layer of fiber (5 speciments). Samples were stored in distilled water of 10 ml each with a temperature of 37°C and a soaking time 7 days. Water absorption was measured in units mg/mm3 which had been measured with electronic digital weighing scales 0.01 mg accuracy (Mettler Toledo, Switzerland). Data were analyzed using the Kruskal-Wallis with 0.05 significance. The results showed the average water absorption of the group without fiber, FRC with 1 layer of fiber and FRC with 2 layer of fiber were 0.01±0.00 mg/mm3, 0.02±0.00 mg/mm3 and 0.02±0.01 mg/mm3. Kruskal-Wallis test showed the value of 0.12 (p>0.05), it can be concluded that there was no significant effect between the number of layers of fiber to water absorption at FR