PENGARUH pH ASAM TERHADAP KEKUATAN FLEXURAL FIBER REINFORCED COMPOSITE JENIS ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE (UHMWPE)

Fiber Reinforced Composite is a material made of matrix that is reinforced by fibers and coupling agent as a binder. The use of FRC in the oral environment involves the interaction between the FRC and saliva with pH variation, which could be Acidic pH. Acid condition could reduce flexural strength of FRC, this is due to the matrix degradation process in acid condition. The aim of this study was to evaluate the effect of acidic pH on flexural strength of fiber reinforced composite with UHMWPE fibers. Twelve bar shaped speciments of 25 mm x 2 mm x 2 mm were cured by LED curing unit, then divided into three groups. Three speciment groups were immersed in artificial saliva with pH variatons (2.5, 4.5, 5.5) and stored in incubator at 37ºC for 14 days. The solutions were changed daily to keep the acidic pH stable. The Flexural strength measured using universal testing machine, the speed was 1 mm/minute and the distance between was 20 mm according to ISO 10477. The value of flexural strength then analyzed using one way ANOVA and LSD0,05. The mean flexural strength of FRC with pH 2.5, 4.5, 5.5 Immersion were 49.53±1.53 MPa, 70.68±1.77 MPa, 74.19±2.32 MPa. ANOVA analysis revealed a significant influence of acidic pH and flexural strength (p