Recycling and reuse of waste dental mould
Loading...
Date
2019-05
Authors
Mohamad Azim Bin Azahari
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Dental stone waste is an α form of calcium sufate hemihydrate with improve properties of Plaster of Paris. The abundance of calcium source inside dental stone make it suitable for bioceramics. In recent decades, researchers and scientist took much attention in bioceramics especially hydroxyapatite (HA) and tricalcium phosphate (TCP). In this work, it has two section were attempted; synthesis of apatite bioceramics from dental mould waste and heat treatment of dental mould waste to reuse it as raw material for making a dental mould. The characterizations of synthesized samples include XRD, FTIR, SEM, EDX as well as density and porosity analysis, shrinkage analysis, hardness test, compression test and Simulated Body Fluid test. During the synthesis of apatite bioceramics project, the dental mould waste was through the process of Chromite Ore Processing Residue (COPR), followed by caustic leaching with 5M, 7M and 10M Sodium Hydroxide (NaOH) solution. The result using 10M NaOH in caustic leaching was able to remove a lot of chromium content of leached residue and forming the white colour of apatite bioceramic material when reacting with Orthophosphoric acid. After the sintering process at 1100°C and 1250°C, it was detected Tricalcium Phosphate (TCP) as the main phase of apatite material. However, the weight percentage was different between both sintering temperature. For the second project, dental mould waste was prepared by heat treatment at temperature 140°C and 160°C for 2 hours and 4 hours. After heat treatment, the main phase detected was similar to gypsum. Thus, the resulting proof that heat treatment process can be reuse to use as raw material for the dental mould again.