OBJECTIVES: This study aims to fabricate graded composite structures with different ceramic materials and explore the effect of the various ceramic materials on the microstructure, surface topography, crystal characterization, bioactivity, and mechanical properties of the ceramic scaffold.
MATERIALS AND METHODS: Ceramic matrix specimens were prepared with a slip casting technique. After sintering, specimens were examined for their physical, chemical, and mechanical properties including microstructure, surface roughness, elemental composition, crystal characterization and biaxial flexural strength. Specimens from each group were immersed in a calcification solution and were evaluated for the deposition of calcium phosphate through microscopy, elemental analysis, and crystal characterization.
RESULTS: Graded ceramic matrix materials were successfully fabricated using a slip-casting technique. Scanning electron microscopy revealed different surface topography as well as the deposition of calcium phosphate crystals on the specimen surface after immersion in calcification solution. Elemental composition and X-Ray Diffraction (XRD) spectra confirmed phase transformation in the composite specimen after sintering. Particle grain size significantly affected surface topography in terms of surface area roughness and topographical patterns. Moreover, the combination of alumina and bioactive glass improved mechanical properties compared to bioactive glass alone.
CONCLUSIONS:
1. The ceramic matrix containing bioactive glass presented greater surface roughness compared to other ceramic matrix without bioactive glass.
2. Two crystal phases: tricalcium silicate (Ca3Si3O9) and calcium metasilicate (CaSiO3) were found in high temperature sintered bioactive glass. The combination of bioactive glass with alumina or hydroxyapatite presented another tricalcium silicate phase such as Ca3(SiO4)O.
3. The XRD analysis of the combination of alumina and hydroxyapatite detected two new phases including grossite (CaAl4O7) and calcium aluminophosphate (Ca9Al(PO4)7).
4. Ceramic matrix containing bioactive glass or hydroxyapatite presented greater deposition of calcium phosphate crystals while the combination of bioactive glass and hydroxyapatite showed the greatest amount of the precipitated crystals.
5. Alumina ceramic matrix showed the highest biaxial flexural strength while hydroxyapatite and bioactive glass presented low biaxial flexural strength.
6. The combination of alumina with hydroxyapatite or bioactive glass improved biaxial flexural strength.
7. The combination of hydroxyapatite with bioactive glass had lower biaxial flexural strength compared to a single-phase ceramic matrix.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/42837 |
| Date | 03 August 2021 |
| Creators | Teerakanok, Supontep |
| Contributors | Giordano, Russell A. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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