Self-synthesize and flexural strength test porcelain from Indonesian natural sand

Abstract

Dental porcelain is usually used for aesthetic indirect restoration. Porcelain powder is still imported, although Indonesia is rich with natural sand as porcelain raw material. Flexural strength is a mechanical property which is related to porcelain's ability to resist occlusal force. The objective of this study is to synthesize porcelain from the mixture of Sumateran and Javanese natural sand and evaluate its flexural strength. This experiment used explorative descriptive method. Feldspar Pangaribuan (65% wt), silica Belitung (25%wt), kaolinite Sukabumi (5%wt), and potassium salt (5%wt) was mixed with wet-ball mill and dissolved by fritting to produce porcelain powder. Five samples were made by liquid-phase method in size 3mm x 2cm x 7cm. XRD test was used to analyse crystalline formed and flexural strength of these samples was measured by Netzch Universal Testing Machine with 7.5kg initial load and calculated by flexural strength formula. The result was porcelain powder which has been sintered on 1150 °C contain leucite (potassium aluminium silicate) crystalline on XRF test with average flexural strength 26.678 MPa. Leucite crystalline is the main indicator for synthesizing dental porcelain because leucite is not usually found on other ceramic. Leucite crystalline is known for increasing strength, preventing crack propagation, and resisting pyroplastic flow. Ten percent of leucite on X-Ray Fluoroscence shows the percentage is less than other dental porcelain. The conclusion of this research is that porcelain succeeded to be self-synthesized from the mixture of Sumateran and Javanese natural sand and having flexural strength 26.678 MPa.