Nanosilika dari Sekam Padi sebagai Penguat Lapisan Opak pada Retainer Gigi Tiruan Jembatan Keramik-Logam

Abstract

Rice husks are organic waste that their utilization remains not optimum in Indonesia. Given that a relatively high silica content within the waste, then these husks have a potential usage to be source of silica as a reinforcing material for opaque porcelain powder in Metal-Ceramic retainer of Fixed Partial Dental Prostheses (FPDs). This study aims to use the nanosilica synthesized from rice husks as a reinforcer on opaque porcelain powder in the preparation of metal-ceramic samples. The nanosilica was synthesized from rice husks via sol-gel methods with the presence of 1N HCl and the sonication process with ultrasonic homogenizer for 270 minutes. The nanosilica was then used as the reinforcer into the commercial opaque porcelain powder with variation of mixture i.e., 0.5%; 1%; 1.5%; 2%; 2.5%; 3% and without mixing. Furthermore, morphological characterizations were carried out through SEM, TEM and PSA, and the physico-chemical properties were determined through FT-IR, XRD, XRF and SEM- EDX instrument. A samples of Co-Cr metal measured with dimension of 25 x 3 x 0.5 mm was prepared to 140 samples. The veneering of opaque and dentine porcelain with dimension of 8 x 3 x 1.1 mm on metal samples were carried out via manually-handed lay out method, and then the coated metal samples were placed for sintering treatment at 920-950°C. The mechanical properties were characterized via flexural, compression, shear, and hardness tests. The FT-IR results confirmed the presence of silica in the form of siloxane, silanol and xiloxy groups at wavenumbers of 1063 cm-1, 960 cm-1, and 793 cm-1 respectively; the XRD results showed 2θ of silica with an angle of 22.7° amorphous structure; XRF results obtain pure silica of 99.50%; while the PSA results show a nanosilica particle size of 28.0 ± 9.6 nm; SEM and TEM result depicted spherical shapes that agglomerate with one to another to form clusters; and the SEM-EDX results confirmed the highest amount of silica in sample with 1% of ratio. The results of statistical analysis showed a significant effect on mechanical properties of metal-ceramic samples through the mixing of nanosilica with ratio 0.5%; 1% and 1.5% (p<0.05). The nanosilica can be synthesized from rice husks via sol-gel and sonication methods, then mixing with opaque porcelain powder can increase the mechanical properties of metal-ceramic samples.