Modification of novel Portland based cement for orthopaedic application

Moetazedian, Amirpasha (2018). Modification of novel Portland based cement for orthopaedic application. University of Birmingham. M.Sc.

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Abstract

Portland cement (PC) is a ceramic hydraulic cement which has been used in construction for decades and more recently for dental applications. PCs possess high durability and compressive strength and demonstrate good biological responses, that are generating interest as a potential material for orthopaedic applications. The present study investigated the addition of porogens to induce large macropores e.g. > 100 µm to promote potential bone ingrowth, whilst retaining appropriate mechanical and physical properties for vertebroplasty used to stabilise fractured vertebral bodies.
The cements containing 20 wt% bismuth oxide (radiopacifying agent) and 5 wt% calcium chloride (setting accelerant) were prepared using a range of powder-to-liquid ratios and porogens (including mannitol, sucrose and sodium bicarbonate or foaming agents) were added from 1-20 wt% to induce macroporosity either after or during setting of the cement. Increasing the concentration of sugars increased the initial setting time 3-fold, whilst causing the cement paste to behave as a liquid. The compressive strengths of modified cements were reduced by up to 90 % after 7 days of storage through increasing flaws and porosity. The macrostructural analysis using scanning electron microscopy (SEM) showed no major difference between the modified cements and controls. 10 wt% foamed gelatine (FG) was found to improve the viscosity of the paste so that it was readily injectable, and demonstrated sufficient cohesion after injection. FG doubled the setting time approximately and generated large interconnected pores ranging from 100-400 µm in diameter according to SEM images. The compressive strengths of foamed cements were sufficiently high after 7 and 30 days of storage to stabilise fractured vertebral bodies.
The addition of 10 wt% FG has shown the potential to modify PC by inducing large pores, whilst maintaining high injectability and compressive strength, which warrants further testing for clinical application in verterbroplasty.

Type of Work:

Thesis (Masters by Research > M.Sc.)

Award Type:

Masters by Research > M.Sc.

Supervisor(s):