| dc.description.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. | en_US |
