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Abstrak :
Penelitian ini bertujuan untuk menginvestigasi efek konsentrasi dan temperatur pencampuran terhadap sifat rheologi dan morfologi dari campuran poly(L-lactic acid) (PLLA) dan agar-agar untuk aplikasi implan yang dapat terdegradasi. Studi ini menggunakan metode pencampuran melt-blending dengan variasi komposisi agar-agar (0%, 4%, 8%, dan 12%) pada dua suhu pencampuran berbeda, yaitu 160°C dan 180°C. Karakterisasi dilakukan melalui pengujian rheologi osilasi dan rotasional, serta pengamatan morfologi permukaan dan patahan menggunakan Scanning Electron Microscopy (SEM). Hasil pengujian menunjukkan bahwa viskositas campuran PLLA dan agar-agar menurun seiring dengan meningkatnya konsentrasi agar-agar dan suhu pencampuran. Pada suhu 180°C, viskositas menurun lebih signifikan dibandingkan pada 160°C. Pengujian rheologi osilasi menunjukkan bahwa modul penyimpanan (G') dan modul kehilangan (G") dari campuran cenderung menurun seiring dengan peningkatan konsentrasi agar-agar, yang menunjukkan penurunan kekakuan dan peningkatan sifat viskoelastis dari material. Pengamatan morfologi permukaan dan patahan dengan SEM menunjukkan bahwa penambahan agar-agar menghasilkan distribusi partikel yang lebih homogen, tetapi juga meningkatkan jumlah retakan pada permukaan material. Pada suhu pencampuran yang lebih tinggi (180°C), material menunjukkan homogenitas yang lebih baik, namun dengan peningkatan jumlah retakan dan kekosongan (voids). Penelitian ini menyimpulkan bahwa komposisi campuran PLLA dan agar-agar serta suhu pencampuran memiliki pengaruh signifikan terhadap sifat rheologi dan morfologi dari material. Campuran dengan komposisi 96% PLLA dan 4% agar-agar pada suhu 160°C menunjukkan sifat mekanik dan morfologi terbaik untuk aplikasi implan mampu luruh. Sampel P96A4T1 yang memiliki nilai torsi yang meningkat secara bertahap tetapi tetap dalam rentang yang dapat dikelola, dimulai dari nilai torsi awal adalah 204 Nm pada detik ke-17 dan mulai stabil pada detik ke-34 dengan nilai torsi sebesar 94 Nm. Selain itu, hasil SEM menunjukkan bahwa Pada P96A4T1, struktur permukaan terlihat lebih homogen dengan sedikit retakan dibandingkan dengan sampel lain. ......This research aims to investigate the effects of concentration and mixing temperature on the rheological and morphological properties of poly(L-lactic acid) (PLLA) and agar blends for degradable implant applications. The study employed the melt-blending method with varying agar concentrations (0%, 4%, 8%, and 12%) at two different mixing temperatures, 160°C and 180°C. Characterization was performed through oscillatory and rotational rheology tests, as well as surface and fracture morphology observations using Scanning Electron Microscopy (SEM). The results indicated that the viscosity of the PLLA and agar blends decreased with increasing agar concentration and mixing temperature. At 180°C, the viscosity decreased more significantly compared to 160°C. Oscillatory rheology tests showed that the storage modulus (G') and loss modulus (G") of the blends tended to decrease with increasing agar concentration, indicating a reduction in stiffness and an increase in the viscoelastic properties of the material. Surface and fracture morphology observations using SEM revealed that the addition of agar resulted in more homogeneous particle distribution but also increased the number of surface cracks. At the higher mixing temperature (180°C), the material exhibited better homogeneity but with an increase in cracks and voids. The study concludes that the composition of PLLA and agar blends and the mixing temperature significantly affect the rheological and morphological properties of the material. The blend with 96% PLLA and 4% agar at 160°C exhibited the best mechanical and morphological properties for degradable implant applications. The blend of 96% PLLA and 4% agar at 160°C showed the best mechanical and morphological properties for implant shedding applications. Sample P96A4T1 had a torque value that increased gradually but remained within a manageable rang,. In addition, the SEM results show that in P96A4T1, the surface structure looks more homogeneous with few cracks compared to the other samples.

Abstrak :

Latar Belakang: Siler kalsium silikat bersifat hidrofilik, berikatan secara kimia ke dentin,  membentuk hidroksiapatit, memiliki waktu kerja dan settingideal, dan tidak terjadi penyusutan. Siler resin epoksi yang banyak digunakan saat ini memiliki kekurangan berupa adanya penyusutan saat mengeras. Evaluasi adaptasi siler dapat menentukan kemampuan kerapatan suatu siler. Salah satu metode untuk mengevaluasi kemampuan kerapatan siler adalah dengan Scanning Electron Microscopy (SEM). Tujuan: Menganalisis perbedaan adaptasi siler pada sepertiga tengah dinding saluran akar antara siler berbahan dasar kalsium silikat dengan resin epoksi.Metode: Tiga puluh dua sampel gigi premolar mandibula dibagi menjadi dua kelompok, yaitu kelompok 1: siler resin epoksi dan kelompok 2: siler kalsium silikat. Sampel dipreparasi dan diobturasi dengan siler berbahan dasar kalsium silikat dan resin epoksi. Selanjutnya, gigi dipotong vertikal dan disiapkan untuk analisis adaptasi siler menggunakan SEM. Data tersebut dianalisis secara statistik dengan uji Chi-square. Hasil Penelitian: Tidak terdapat perbedaan bermakna antara adaptasi siler kalsium silikat dan resin epoksi secara statistik (p>0.05). Partikel resin epoksi secara keseluruhan tampak berukuran lebih besar dibandingkan dengan kalsium silikat. Kesimpulan: Tidak terdapat perbedaan adaptasi siler secara statistik antara siler berbahan dasar kalsium silikat dengan resin epoksi pada sepertiga tengah dinding saluran akar, namun secara klinis sampel siler kalsium silikat lebih sedikit menunjukkan gap/ celah dan lebih banyak yang berpenetrasi ke dalam tubuli dentin dinding saluran akar.

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Background: Calcium silicate sealer is hydrophilic, chemically bonded to dentin, forms hydroxyapatite, has an ideal working and setting time, and does not shrink. The epoxy resin sealer that is widely used today has the disadvantage of shrinkage when hardening. Evaluation of the adaptation of the sealer can determine the sealing ability of a sealer. One of the method for evaluating the sealing ability of a sealer is Scanning Electron Microscopy (SEM). Objective: To analyze differences in the adaptation of sealers in middle third of root canal wall between the calcium silicate and epoxy resin based sealer. Methods: Thirty-two mandibular premolar teeth samples were divided into two groups, that are group 1: epoxy resin sealer and group 2: calcium silicate sealer. Samples were prepared and obturated with calcium silicate and epoxy resin based sealer. Next, the teeth were cut vertically and prepared for analysis of the sealer adaptation using SEM. The data was analyzed statistically by Chi-square test. Results: There was no significant difference between the adaptation of calcium silicate and epoxy resin sealer statistically (p> 0.05). Overall epoxy resin’s particles appear larger than calcium silicate. Conclusion: There was no statistical difference in the adaptation of sealers between calcium silicate and epoxy resin based sealer in middle third of root canal wall, but clinically fewer calcium silicate sealer samples showed gaps and more penetrated into dentinal tubules of root canal wall.

 

Abstrak :
There is an abundant source of naturally occurring mordenitein the Bayah region of Indonesia. In this work we studied how acid dealumination of this indigenous zeolite affected its physical, chemical and catalytic properties. The results are compared to those obtained with another natural mordenite and a commercially available synthetic mordenite. Acid dealumination of mordenites is known to affect the pore structure and therefore enhance the adsorption-properties of the zeolite and the accessibility to its acidic sites. A series of dealuminated mordenite samples were prepared. They were refluxed in constant boiling HCl as a function of time. The samples were each subsequently exchanged with IN ammonium nitrate. The Si/Al ratio was determined by X-Ray Fluorescence. The presence of other metals was detected with Atomic Adsorption Spectroscopy and Inductively Coupled Plasma Spectroscopy. Nitrogen Adsorption was used to determine the surface area and the pore size distribution. Crystallinity and unit cell size were determined via X-Ray Diffraction. The surface morphology was probed with Scanning Electron Microscopy. An n-hexane cracking test was utilized to probe catalytic activity and selectivity. The results of this study indicate that up to and including sixteen hours of reflux, dealumination of this natural Indonesian mordenite increases the crystallinity and the average pore size, however the surface area and the unit cell size remain constant. Additional reflux, beyond sixteen hours, destroyed a portion 'of the zeolitic framework, indicated by a loss in crystallinity. Cracking activity increased through sixteen hours .of ref lux and was found to be constant thereafter. Total' C2, C3 and C4 {including isobutene) selectivity improved through sixteen hours of reflux and then also remained constant. In comparison to a commercially available sample of synthetic mordenite, the modified Indonesian mordenite ,is less active, but has comparable selectivity. However, compared to the naturally occuring U.S. mordenite, the modified Indonesian mordenite has improved physical and catalytic properties.

Abstrak :
Latar Belakang: Semen ionomer kaca (SIK) merupakan bahan tumpat berbahan dasar air yang cukup populer, tetapi memiliki kelemahan pada sifat mekanisnya. Seiring perkembangan teknologi, ditemukan bahan tumpat baru yaitu Giomer. Keduanya memiliki keunggulan berupa sifat pelepasan fluoride, sehingga diharapkan Giomer dapat menutupi kekurangan SIK yang terletak pada sifat mekanisnya, salah satunya kekuatan tekan. Beberapa penelitian menyatakan bahwa sifat mekanis suatu material berhubungan dengan morfologi permukaan dan komposisi kimia. Tujuan: Mengetahui perbandingan kekuatan tekan SIK dan Giomer, serta hubungannya dengan morfologi permukaan dan komposisi kimia. Metode: 16 spesimen SIK dan Giomer disiapkan untuk uji kekuatan tekan lalu dianalisis dengan uji Independent T-test. Kemudian spesimen SIK dan Giomer disiapkan untuk analisis morfologi permukaan dan komposisi kimia menggunakan SEM-EDX. Hasil Penelitian: Terdapat perbedaan bermakna nilai kekuatan tekan antara SIK dan Giomer dengan nilai kekuatan tekan Giomer lebih tinggi (204,67 MPa) dibandingkan dengan SIK (118,59 MPa). SIK memiliki permukaan eksternal yang lebih tidak beraturan, ukuran partikel lebih besar, dan lebih banyak porus. Kandungan silika pada Giomer lebih tinggi. Kesimpulan: Giomer memiliki kekuatan tekan lebih tinggi dibandingkan dengan SIK. Material restorasi dengan morfologi permukaan yang lebih beraturan, lebih sedikit porus, dan ukuran partikel yang lebih kecil dengan susunan yang rapat, serta kandungan silika dan karbon yang lebih tinggi berhubungan dengan kekuatan tekan yang lebih tinggi. ......Background: Glass ionomer cement (GIC) is a water-based filling material that is quite popular, but has a weakness in its mechanical properties. Along with the development of technology, a new filling material was discovered, namely Giomer. Both have advantages in the form of fluoride release properties, so it is hoped that Giomer can cover the shortcomings of GIC which lie in their mechanical properties, one of which is compressive strength. Several studies have stated that the mechanical properties of a material are related to the surface morphology and chemical composition. Objective: To determine the comparison of the compressive strength of GIC and Giomer, as well as their relationship to surface morphology and chemical composition. Methods: 16 specimens of GIC and Giomer were prepared for compressive strength test and then analyzed by Independent T-test. Then the GIC and Giomer specimens were prepared for analysis of surface morphology and chemical composition using SEM-EDX. Research Results: There is a significant difference in the compressive strength value between GIC and Giomer with a higher Giomer compressive strength value (204.67 MPa) compared to GIC (118.59 MPa). GICs have a more irregular external surface, larger particle size, and more porosity. The silica content in Giomer is higher. Conclusion: Giomer has higher compressive strength than GIC. A restorative material with a more regular surface morphology, less porous and smaller particle size with a denser arrangement, and higher silica and carbon content is associated with higher compressive strength.