Fiber Reinforced Composite (FRC) merupakan material sintetik yang banyak diaplikasikan secara klinis di kedokteran gigi seperti pada bidang prostodonti, konservasi gigi, implantologi, periodonti, ortodonti dan kedokteran gigi anak. E-glass fiber merupakan tipe fiber yang sering digunakan di Kedokteran Gigi. Penggunaaannya lebih dari 50% dibandingkan tipe lain. Ketersediaan E glass fiber dental di Indonesia cukup terbatas dengan harga relatif mahal namun tersedia glass fiber non dental dalam jumlah yang banyak dengan harga terjangkau. Salah satu tipe yang banyak digunakan adalah tipe E glass. E glass fiber non dental telah banyak digunakan sebagai material substitusi pada otomotif dan aplikasi kedirgantaraan karena karakteristiknya ringan dan sifat mekanik yang lebih baik. Tujuan dari penelitian ini adalah untuk menganalisis komposisi dari E-glass Fiber Non Dental menggunakan teknik XRF.  Sampel terdiri dari 10 gram E glass fiber non dental. Sampel dipotong dan dihaluskan dengan cara ditumbuk dan diayak. Selanjutnya dianalisis menggunakan X-Ray Fluorescence Spectrometer (XRF). Selanjutnya hasil analisis ditampilkan dalam bentuk tabel deskriptif. Hasil analisis menunjukkan kandungan oksida terbesar SiO2 (39,53%), CaO (46,31%), Al2O3 (8,17%) dan K2O (0,64%) tanpa kandungan B2O3. Berdasarkan analisis XRF disimpulkan bahwa E-glass fiber non dental memiliki komposisi dan konsentrasi yang hampir sama dengan E-glass fiber dental, dan diharapkan dapat menjadi alternatif material di Kedokteran Gigi. Kata Kunci: Glass fiber, E glass fiber dental, E glass fiber non dental, X-Ray Fluorescence Spectrometer (XRF)

The fiber that is most often used in dentistry is E-glass fiber, but in Indonesia E-glass fiber dental is limited by quantity and relatively expensive. E-glass fiber non dental was chosen as an alternative because the composition is almost the same as E-glass fiber dental and commonly used in the engineering world as a booster in the manufacture of gypsum panels, sculptures and automotive components. This study is aimed to determine the color stability difference between fiber reinforced composite (FRC) E-glass fiber dental and E-glass fiber non dental. This quantitative research is an experimental laboratory with a one group pretest and posttest research design. The sample is circular in shape with diameter 13 mm and height 2 mm consisted of E-glass fiber dental group and the E- glass fiber non dental group consisting of 4 samples for each group and given silane. After the color test using Spectrophotometer UV-Vis where the absorbance and wavelength values obtained will be calculated for the area so that the L*a*b* value and analysed using independent sample t-test, it was stated that there was no significant difference between the color of the fiber reinforced composite E-glass fiber dental and the E-glass fiber non dental. It is concluded that the use of E-glass fiber non dental can be used as a clinical standard because it has a good color stability value similar to that of E-glass fiber dental.