UJI KEKERASAN KOMPOSIT TERHADAP RENDAMAN BUAH JERUK NIPIS (CITRUS AURANTIFOLIA)
Abstract
Abstract: Lime (Citrus aurantifolia) contains an acid agent which can affects the surface hardness of composite. Change of surface hardness of composite is caused by infiltration of water containing the acid agent that affects the bonding of matrix to filler of composite.This study aimed to determine the effect of immersed lime on surface hardness of composite. This was an experimental laboratory study with a pre and post test control group design. The samples of resin composite had 5 mm in diameters and 4 mm in thickness (n = 24). Samples were divided into two groups: mineral water as the control group and immersed lime as the trial group. Samples were alternately immersed for 30, 60, 120 minutes. Post immersion, the changes of composite hardness were measured with Mico Vickers Hardness Tester. Post immersion Vickers hardness was compared by using paired t-test. The result showed that immersed lime significantly reduced the surface hardness of composite (p<0.05). Duration of 60 and 120 minutes of lime immersion reduced significantly the surface hardness of composite (p<0.05). It is suggested to reduce the duration of acidic fruit exposure such as lime to the composite.
Keywords: resin composite, surface hardness changes, lime
Abstrak: Buah jeruk nipis (Citrus aurantifolia) mempunyai kandungan asa m yang dapat memengaruhi kekerasan komposit. Perubahan kekerasan komposit disebabkan oleh menyerapnya air yang mengandung asam pada komposit yang memengaruhi ikatan matriks dan filler. Penelitian ini bertujuan untuk mengetahui pengaruh perendaman buah jeruk nipis terhadap perubahan kekerasan komposit. Jenis penelitian ini ialah eksperimental laboratorium dengan desain pre and post test control group. Jumlah sampel penelitian ialah 24 resin komposit dengan diameter 5 mm dan tebal 4 mm. Sampel dibagi menjadi 2 kelompok yaitu kelompok kontrol air mineral dan kelompok perlakuan yang direndam dalam sari jeruk nipis dengan 3 durasi waktu yang berbeda 30, 60, dan 120 menit. Setelah perendaman diukur nilai perubahan kekerasan dengan Mico Vickers Hardness Tester. Hasil perendaman berdasarkan uji Vickers diuji banding secara statistik menggunakan uji paired sample t test. Hasil penelitian menunjukkan adanya pengaruh perendaman buah jeruk nipis terhadap perubahan kekerasan komposit (p<0,05). Pada durasi waktu 60 dan 120 menit terdapat pengurangan yang bermakna dari kekerasan permukaan resin komposit (p<0,05). Disarankan untuk mengurangi durasi paparan komposit terhadap buah-buahan yang mengandung asam seperti jeruk nipis.
Kata kunci: resin komposit, perubahan kekerasan permukaan, jeruk nipis
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PDFDOI: https://doi.org/10.35790/eg.3.1.2015.8198
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