Optimisation of titanium-hydroxyapatite composites using bioactive glass for fabrication of functionally graded dental posts / Mohamed Abdulmunem Abdulateef
Optimisation of the chemical, physical and mechanical properties of Titanium-hydroxyapatite (Ti-HA) composites using various ratios of bioactive glass to fabricate a functionally graded dental posts (FGDPs). Bioactive glass (BG) (containing SiO2, NaO, CaO, B2O3, P2O5, CaF2, MgO, TiO2) was prepar...
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| Format: | Thesis |
| Published: |
2019
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| Online Access: | http://studentsrepo.um.edu.my/12627/4/abdulmunem.pdf http://studentsrepo.um.edu.my/12627/ |
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| Summary: | Optimisation of the chemical, physical and mechanical properties of Titanium-hydroxyapatite (Ti-HA) composites using various ratios of bioactive glass to fabricate a
functionally graded dental posts (FGDPs). Bioactive glass (BG) (containing SiO2, NaO,
CaO, B2O3, P2O5, CaF2, MgO, TiO2) was prepared and added in three different ratios
(5%, 10%, and 15%) to five different Ti-HA composites. Section 1; mixtures were
prepared, milled, pressed, sintered and visually checked. In section 2; the optimum ratio
of bioactive glass was selected according to section 1 results and was then added to the
Ti-HA composites and divided into two groups, each containing five layers. Samples in
Group 1 were sintered with an air atmosphere furnace, while samples in Group 2 were
sintered with a vacuum furnace and then all groups were tested with XRD and EDX.
Density, micro-hardness, modulus of elasticity and compression strength was also
measured. Section 3; based on the results in part 2, functionally graded dental posts
(FGDPs) were then fabricated. Section 4; FGDPs and other post types were restored in
endodontically treated teeth with 10 teeth in each group. Fracture resistance and failure
modes were evaluated using a universal testing machine and stereomicroscope and data
were analysed using one-way ANOVA and Chi-square tests. Section 5; stress
distributions were also evaluated using teeth models restored with the FGDPs, titanium,
fibre, and stainless steel posts and analysed using finite element analysis. Ti-HA
composites that were incorporated with a 10% ratio of BG were stable and crack free
when compared to other groups. In the second section, samples sintered in Group 1 (air
atmosphere furnace) showed a significant difference (p= 0.000) as compared to Group 2
(vacuum furnace), in terms of compression strength, micro-hardness values density and
modulus of elasticity. In terms of XRD analysis, Group 1 also showed that major phases
iv
belonged to Ti and HA, and a minimum amount of Ti was oxidised to Ti2O. Whereas, in
Group 2; the main phases belonged to Ti and HA, and the minor phases showed that HA
had decomposed into TCP and TTCP. EDX also showed that there was no
contamination recorded in both groups. In terms of fracture resistance, FGDPS and
titanium groups showed a higher fracture resistance compared to the stainless steel
group (p= 0.000 and p= 0.032, respectively). In terms of failure modes, FGDPs group
also showed higher restorable failures than other groups, followed by the fibre group. In
terms of stress distribution, regardless of load direction, maximum stress was
concentrated at the core-crown interface in the coronal third of the crown, and was the
highest in fibre and FGDPS models, resulting in restorable failures. 10% BG was the
most suitable ratio to be added to Ti- HA composites compared to other ratios. Sintering
Ti-HA-BG composites using air atmosphere furnace resulted in better chemical,
physical and mechanical properties compared to those sintered in vacuumed furnace. It
was found that teeth restored with FGDPs and titanium posts showed a higher fracture
resistance than those restored with stainless steel posts. Failure modes tended to be more
restorable with teeth restored with FGDPs than those restored with other types of dental
post. Stress distribution was uniformly distributed in FGDPs and fibre models as
compared to titanium and stainless steel models. |
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