Hamad, Wan Nur Fadilla Wan
(2022)
Antibacterial polymethylmethacrylate (PMMA)/ beta tri calsium phosphate/ zinc oxide composites for craniofacial reconstruction.
PhD thesis, Universiti Sains Malaysia.
Abstract
Polymethylmethacrylate (PMMA) is commonly used in dental and bone
reconstruction applications due to the excellent properties such as biocompatible,
biologically inert and rigid. In craniofacial, traumatic injuries will result to the defect
of underlying brain. Somehow, after reconstruction of scull using PMMA, the
infection may occur. Thus, incorporation of antibacterial agent such as beta tricalcium
phosphate (β-TCP) to the PMMA is desirable to eliminate infection. Also, the presence
of β-TCP to the composites is one of the alternatives to promote cell growth to the
surrounding bone tissue. Hence, in this study, PMMA composites fabricated with
specified percentages of filler content of β-TCP and Zinc Oxide. The composites
divided into three groups of different percentages of 5, 10, 15% β-TCP without ZnO,
and another two groups, 2.5% and 5% ZnO were added 15% β-TCP. The size of β-
TCP was approximately 1-5μm and ZnO was in nano size (256nm). The mechanical
characteristics, chemical bonding, and physical properties of the specimen were next
assessed. The characterization of specimen was then evaluated for mechanical
properties, chemical bonding, physical properties. Observations of the microstructure
of the fracture surface were performed by Field Emission scanning electron
microscopy (FESEM). Chemical groups existed were confirmed with analysis of
Fourier Transmission InfraRed (FTIR). The mechanical properties showed the
improvement for PMMA composites. There is significant difference detected between
PMMA pure and PMMA composites in physical properties. The cytotoxicity effect was investigated through 3-(4, 5-dimethylthiazoyl)-2-5 diphenyl-tetrazolium bromide
(MTT assay), using human fetal osteoblast cell (hFOB). The hFOB cultured with 25
mg/ml PMMA filled 15% βTCP and 5% ZnO demonstrated the highest cell viability
(132.73%). The percentages of cell viability of samples with 50 mg/ml and below
showed no cytotoxicity effect due to their value of cell viability were more than 70%.
The antibacterial properties of the PMMA composite were evaluated using agar
diffusion and growth curve methods against Gram positive (Staphylococcus aureus)
and gram negative (Pseudomonas aeruginosa). A significant difference was observed
with the incorporation of ZnO filler in the agar diffusion test. The antibacterial
property of PMMA composites were further evaluated with a growth curve and
significant antibacterial activity was found on PMMA composites with 2.5% and 5%
of ZnO filled. In conclusion, PMMA composites at 2.5% and 5% ZnO, are promising
biomaterials that suit to be applied as implants in craniofacial reconstruction.
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