The effect of TiO2 concentration on properties of apatite-mullite glass-ceramics for dental use

Publication date: Available online 30 December 2015
Source:Dental Materials
Author(s): Hawa M. Fathi, Anthony Johnson
ObjectiveThe aim of this study was to evaluate the effect of TiO2 concentration on the properties of apatite-mullite glass-ceramics namely strength and the chemical solubility to comply with the ISO standard recommendations for dental ceramics (BS EN ISO 6872-2008) [1].MethodsTen novel glass-ceramic materials were produced based on the general formula (4.5SiO2-3Al2O3-1.5P2O5-3CaO-CaF2-xTiO2) where x varied from 0.5 to 5wt%. Glass with no TiO2 added (HG1T0.0) was used as a reference. Discs of 12mm diameter and 1.6mm (±0.2mm) thickness were prepared for both biaxial flexural strength (BFS) and chemical solubility testing, in accordance with the BS EN ISO 6872-2008 [1] for dental ceramics. All produced materials were investigated using differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Energy dispersive X-ray analysis (EDS) was also carried out on some samples to identify the element composition of samples.ResultsIncreasing the concentration of TiO2 from 0.5wt% to 2wt% significantly (P<0.05) increased the chemical solubility of the material. With the material containing 2.5wt% of TiO2, the solubility significantly reduced (P<0.05) and resulted in a solubility value of 228.3μm/cm2 and BFS value of 197.9MPa. Increasing the TiO2 concentration more than 2.5wt%, led to a significant (P<0.05) increase in solubility and a reduction in BFS.ConclusionsTiO2 is an effective agent for improving the durability and the mechanical properties of an apatite-mullite glass-ceramic only up to 2.5wt% concentration.

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