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

Fiber reinforced composite is a material consisted of matrix and reinforcing fiber. The application of FRC in oral cavity as a splint will form a contact between FRC and saliva with fluctuating pH degree, which is saliva can turn into acidic. The aim of this study was to determine the influence of acidic pH on compressive strength of FRC with UHMWPE fiber. Twelve cylindrical samples of FRC with flowable composite (Master Flow, Brazil) as matrix and UHMWPE fiber (Construct, USA) with 3 mm diameters and 6 mm heights were used in this study. All samples were polymerized for 20 seconds, then divided into 3 groups of immersion consists of pH 2,5, 4,5, and 5,5 (n=4). Samples were immersed into artificial saliva solution for 14 days at 37�C. Compressive strength was measured using universal testing machine with 1mm/min speed of press. Data obtained then analyzed using one way ANOVA and LSD tests. Means of compressive strength from the immersion groups pH 2.5, 4.5, and 5.5 were 54.23 ± 1.84, 92.06 ± 2.71, and 101.95 ± 3.34 MPa. One way ANOVA test showed that acidic pH had significant influence on compressive strength (p<0.05). Least significant difference (LSD) test showed significant difference in treatment group of pH 2.5 to treatment groups of pH 4.5 and 5.5 (p<0.05). Conclusion of this study is there is significant influence of acidic pH on the decrease in compressive strength of FRC with UHMWPE fiber

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<0.05). LSD showed significant differences between all treatment groups. Conclusion of this study is acidic pH had a significant influence on the decrease of fiber reinforced composite with UHMWPE fiber flexural strength. The lower flexural strength obtained at pH 2,5 immersion

EFEK SAMPING LAMA APLIKASI DARI BLEACHING AGENT HIDROGEN PEROKSIDA 40% TERHADAP KEKASARAN PERMUKAAN RESIN KOMPOSIT TIPE NANOFIL

Bleaching is a dental treatment uses chemical on discolored vital and nonvital teeth. From many bleaching techniques, there is one name in office bleaching which performed in the dentist's office. Often, the application of bleaching agents does not only touch the healthy tooth tissue, yet it has the potential to touch the tooth tissue that has tooth restoration, for example is the nanofill composite resin. The purpose of this study is to determine the adverse effects of application time of bleaching agent 40% of hydrogen peroxide on the surface roughness of nanofill type composite resin restorations. The study was conducted by an experimental laboratory method. The sample was a nanofill composite resin sample (Filtek Z350, 3M, USA) discshaped with a diameter of 10 mm and a height of 2 mm. Samples were made with a total of 12 samples, which were divided into 3 treatment groups with each group consist of 4 samples. The samples was soaked in aquades and put into incubator for 24 hours at 37OC. The samples applied with bleaching agent 40% hydrogen peroxide (Opalescense Boost, USA) at room temperature (25OC). Each treatment group had a different variation of contact time with bleaching agent, which were: 30 minutes, 45 minutes, and 60 minutes. The surface roughness was measured before and after the application of bleaching agent. Then the data delta (�) of surface roughness were statistically analyzed using One-Way ANOVA followed by LSD0,05 significance test. Results showed the mean and standard deviation of delta (�) of the initial and final surface roughness of nanofill composite resin with 30 minutes of contact time was 0.040 ±0.016 �